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Aneurysmal bone cyst of the temporal bone
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Aneurysmal Bone Cyst of the Temporal Bone Sinan Cakirer, MD, Muzaffer Basak, MD, Irfan Celebi, MD, Fevziye Kabukcuoglu, MD, and Yesim Erdem, MD
Aneurysmal bone cysts are benign fibrosseous lesions of the bone that are rarely detected in the temporal bone. Seventeen cases of aneurysmal bone cysts with histological confirmation involving the temporal bone were reported in the literature. We report a case of left temporal aneurysmal bone cyst in a 52-year-old male with the clinical findings of periauricular painful swelling, decreased hearing, and facial paralysis. A magnetic resonance image of the patient showed a well-circumscribed multi-loculated expansile lesion of the left temporal bone during the first admission to the hospital. The lesion recurred 1 year after the subtotal resection with a more solid appearance. In addition, we review the literature for these rare lesions.
Aneurysmal bone cysts (ABC) are benign, nonneoplastic, osteolytic, and expansile lesions of the bone. The most common locations for ABCs are the metaphyses of long bones, vertebrae, and flat bones. They are usually detected in patients in the first 2 to 3 decades of their lives.1 ABC of the skull is an unusual entity, and the reported incidence is around 2.5% to 6% of the cases.2-5 ABCs are very rarely found in the temporal bone; there are 17 cases with histological confirmation reported in the literature.6-20 We present a case of ABC of the temporal bone that revealed characteristic magnetic resonance imaging (MRI) findings, and recurred after the subtotal resection of the lesion with a more solid MRI and histological appearance. We also review all of the available cases with histological
From the Department of Radiology; and the Department of Pathology, Istanbul Sisli Etfal Hospital, Istanbul, Turkey Reprint requests: Sinan Cakirer, 67 Ada, Kardelen 4/2, Daire 37, 81120 Ataþehir, Istanbul, Turkey. E-mail: [email protected]. Curr Probl Diagn Radiol 2003;32:169-175. © 2003 Mosby, Inc. All rights reserved. 0363-0188/2003/$30.00 ⫹ 0 doi:10.1016/S0363-0188(03)00025-2
Curr Probl Diagn Radiol, July/August 2003
confirmation of ABCs involving the temporal bone (Table 1). The final diagnosis is the histological examination of a surgical specimen; however, preoperative MRI study of the patient should be performed both to differentiate ABC from other lytic lesions and to determine a surgical strategy for the lesion.
Case Description A 52-year-old man presented with a left-sided painful preauricular swelling, severe headache, decreased hearing, and facial asymmetry, developing over a period of approximately 6 months. The neurological examination of the patient detected severe sensorineural hearing loss and facial paralysis on the left side, and bilateral papilledema and mild pyramidal findings on the right side. A cranial MRI study was performed in three orthogonal planes with a standard head coil on a 1.5-T MR scanner (Picker Eclipse, Picker International, Cincinnati, OH). Spin-echo (SE) T1-weighted images (repetition time ms/echo time ms, 430/15), fast spin echo (FSE), proton-density (PD), and T2weighted images (repetition time ms/echo time ms, 3200/30 and 3200/112) in the axial plane, FLAIR images (repetition time ms/echo time ms/inversion time ms, 6000/95/1800) in the coronal plane, and SE T1-weighted images (repetition time ms/echo time ms, 330/15) in the sagittal plane were obtained. Spin-echo T1-weighted sequences were repeated in three planes after intravenous administration of gadopentetate dimeglumine (Magnevist; Schering, Berlin, Germany) at a dose of 0.15 mL/kg. Slice thickness and interval values were 5 mm and 2 mm, respectively, for the whole examination protocol. MRI of the patient revealed a well-circumscribed multi-loculated lesion that originated from the left
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TABLE 1. Cases of histologically proven aneurysmal bone cysts involving the temporal bone, reported between 1970 –2002 in the literature No. Year/ref Age/sex Clinical findings Location Histology Treatment Result 1
19776
14 year/M
Enlarging head swelling, headache, neck pain
2
19797
16 year/F
3
19808
62 year/M
4
19849
36 year/M
5
198510
36 year/M
6
198510
19 year/F
7
198811
23 year/F
8
199312
8 year/M
Headache, enlarging mass Sudden loss of consciousness, 3rd nerve palsy Decreased hearing, transient impairment of vision, facial weakness Seizure, deafness, 7th nerve palsy, 5th nerve sensory loss Headache, exophthalmos, diplopia Otalgia, severe endolabyrinthic- type perception deafness Recurrent meningitis
9
199413
14 year/F
10
199413
11
R Temporooccipital LT
ABC
ABC
Aspiration biopsy, then total resection Total resection
LT
ABC
Total resection
RT
ABC
Total resection
Unknown
LT
ABC
Total resection
Recurrence free for 2.5 years
LT
ABC
Total resection
RT-O
ABC
Curettage
Recurrence free for 1.5 years Unknown
RT
ABC
Total resection
Painless facial swelling
RT
Total resection
22 year/M
Ptosis,decreased vision
LT
Fibrous dysplasia with ABC FD with ABC
199514
10 year/F
RT
ABC
Total resection
12
199515
28 year/M
LT
ABC
Radiotherapy and excision
Unknown
13 14
199816 199917
13 year/M 9 year/M
Progressive hearing loss, headache, stenotic external auditory canal Painful swelling behind left ear, headache, decreased hearing Facial swelling Posterior auricular pain
LT LT
ABC ABC
Total resection Total resection
15 16
199918 200019
15 year/M 5 year/F
ABC ABC
Total resection Total resection
17
200120
5.5 year/M
RT RTsphenoid RT
AC
Total resection
18
Present case
52 year/M
LT
ABC
Subtotal resection
Unknown Recurrence free for several weeks Unknown Recurrence free for 27 months Recurrence free for several months Recurrence 1 year after surgery
Decreased hearing Posterior auricular tough and fixed swelling Proptosis, temporal swelling Decreased hearing, facial paralysis, periauricular pain and swelling
Total resection
Unknown
Recurrence free for 1.5 years Recurrence free for 2 months
Recurrence free for 1 month Recurrence free for 2 years Recurrence free for 1 year Recurrence free for 6 weeks
(Ref: reference no, M: male, F: female, R: right, L: left, T: temporal, ABC: aneurysmal bone cyst).
temporal bone. The cystic mass caused expansion of the diploic space of the temporal bone, with thinning and some focal disruptions of external and internal tables. The lesion contained a thin peripheral capsule and thin internal septations that revealed hypointense signal-intensity characteristics on all sequences, and intense contrast enhancement after intravenous gadolinium administration. The internal septa separated multiple cystic cavities of variegated signal intensities. The lesion was detected to extend toward the intracranial direction, and caused a prominent compression on the neighboring temporal lobe, and indirectly on the
170
frontobasal lobe and left cerebral peduncle. The mass caused the effacement of left sylvian cistern and left-sided lateral ventricle compartments, as well as an additional contralateral subfalcian shift of the midline structures. The mass showed an epidural extension; the dural layer and peripheral capsule of the lesion on the cranial side were not clearly differentiated from each other on MRI pictures, and they enhanced strongly with intravenous gadolinium administration. The mass also showed some degree of extracranial extension associated with the edema of overlying temporalis muscle and scalp (Fig 1). MRI of the
Curr Probl Diagn Radiol, July/August 2003
patient was strongly suggestive for a radiological diagnosis of aneurysmal bone cyst of the temporal bone. The lesion was subtotally resected until the dura was reached; the dura was infiltrated with the mass extending beyond the fibrous capsule medially. The histological examination of the specimen showed a highly vascular lesion composed of numerous bloodfilled sinusoidal spaces without endothelial linings, separated by multiple septations. The fibrous capsule and septations contained multiple spindle-shaped fibroblasts and some multinucleated giant cells, hemosiderin-laden macrophages, and extravasated red blood cells. New bone formation was also evident within some septations (Fig 2). The histological diagnosis was consistent with the aneurysmal bone cyst of the temporal bone. Left-sided preauricular painful swelling and rightsided mild pyramidal findings promptly regressed within 1 month and the patient’s headache almost disappeared in 6 weeks, but the degree of hearing loss and facial paralysis did not change considerably. The patient complained of severe headache and periauricular painful swelling almost 1 year after the surgical therapy. A control cranial MRI study was repeated on the same MRI scanner with the same technical parameters and protocol. A lesion was detected in the temporal bone— but with a lower location than the previous one—that had a peripheral thin capsule and multiple thin septations separating multiple minute cyst-like cavities. The cyst-like cavities were filled with an intense material. The fibrous capsule and internal septations revealed intense contrast enhancement after intravenous gadolinium administration. The
FIG 1. (A) Axial fast spin-echo T2-weighted MRI (repetition time ms/echo time ms, 3200/112) shows a well-circumscribed left-sided multi-cystic temporal lesion with a peripheral hypointense capsule and internal hypointense septations. The cystic mass causes expansion of the diploic space of the temporal bone, with thinning of external and internal tables. The cavities are filled with hyperintense fluid. (B) Coronal FLAIR MRI (repetition time ms/echo time ms/inversion time ms, 6000/95/1800) reveals the extension of lesion toward the intracranial direction, causing a prominent compression on the neighboring temporal lobe. The mass causes the effacement of left sylvian cistern and left-sided lateral ventricle compartments, and an additional contralateral subfalcian shift of the midline structures. (C) Axial postgadolinium spin-echo T1-weighted MRI (repetition time ms/echo time ms, 430/15) shows intense contrast enhancement of the left temporal lesion at its periphery and internal septations. Dural layer and peripheral capsule of the lesion on the cranial side are not clearly differentiated from each other. The mass shows some degree of extracranial extension associated with the edema of overlying temporalis muscle and scalp as well.
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171
FIG 2. (A) Microphotograph of the surgical specimen shows cystic spaces containing red blood cells, which are separated by septa composed of spindle-shaped fibroblastic cells and some scattered multinucleated giant cells (hematoxylin-eosin stain; original magnification, ⫻100). (B) The septum contains areas of reactive osteoid formation with some scattered multinucleated giant cells, and cystic spaces contain plenty of red blood cells (hematoxylin-eosin stain; original magnification, ⫻200).
neighboring dural layers were infiltrated with the outer margin of the lesion. The mass caused some compression on the neighboring temporal lobe; however, the frontal lobe, brainstem, and lateral ventricles were all free of compression, except for mild effacement of left sylvian fissure. The mass extended toward infratemporal fossa as well. The lesion showed some extracranial extension associated with the edema of overlying temporalis muscle and scalp (Fig 3). MRI suggested the recurrence of the aneurysmal bone cyst of temporal bone. A second surgical operation was planned after the excisional biopsy of lesion, which confirmed the diagnosis of ABC with a more cellular histological appearance that was accepted as a solid variant of ABC.
Discussion In 1942, Jaffe and Lichtenstein coined the term “aneurysmal bone cyst” to identify a peculiar entity: an expanding bony lesion with a vascular lining and a characteristic radiological appearance of a soap bubble.21 ABCs are benign, but expansile and locally aggressive lesions of the bone, containing thin-walled blood-filled cystic cavities that are lined by connective tissue with giant cells and trabecular bone. ABCs represent 6% of the bone tumors. They are most commonly found in the shafts of the long bones with eccentrical metaphyseal location, and the posterior elements of the vertebrae. Only 2.5% to 6% of the
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lesions arise from the bones of skull.1-5,21,22 Temporal ABCs are very rare entities, reported in only 17 cases in the English literature.6-20 Approximately 75% to 90% of the ABCs occur in patients younger than 20 years of age.2,4,5 Most of the reports, including the paper for ABCs of the skull by Sheikh, showed no sex predominance for ABCs.4 From the collected 17 cases involving the temporal bone, 6 patients were female and 11 patients were male. This finding shows that ABCs of the temporal bone have a predilection for the male sex. The ages of patients, excluding our present case, ranged from 5 years to 62 years, with a mean age of 19.4 years.6-20 Most experiences with ABCs have been obtained from the lesions located in the long bones and vertebrae. They may be primary or secondary. Although some theories have been proposed, the exact cause of primary ABCs is not yet clear. The development of focal dynamic alterations with secondary venous hypertension may cause a slow expansion of the cortex, according to Lichtenstein. A history of local trauma has been reported before the development of ABCs in some other papers; however, in many cases there has been no history of trauma. The view that there is a basic underlying arteriovenous anomaly resulting in dilated vascular spaces seems to provide a good explanation for the histological features and clinical course of ABCs.15,20,23,24 In the long bones, nearly one third of the lesions are considered secondary to the
Curr Probl Diagn Radiol, July/August 2003
preexisting bone lesions; recently, a similar association has been observed in ABCs of the skull as well. Secondary ABCs arise from pre-existing bone lesions such as giant cell tumor, osteoblastoma, chondroblastoma, nonossifying fibroma, angioma, fibrous dysplasia, unicameral bone cyst, and chondromyxoid fibroma.1,3,4,15 A similar association is present in two cases of ABC of the temporal bone with a medical history of fibrous dysplasia involving the temporal region.13 However, our present case did not have any associated pre-existing lesion of that area, nor a history of trauma, so he was accepted to have a primary ABC of the temporal bone. Clinical findings of temporal ABCs are related to the presence and location of the mass lesion. The most common mode of presentation for temporal ABCs is the swelling around the temporal region that may or may not be associated with pain. Other presenting symptoms are decreased hearing, 5th and 7th cranial nerve paralyzes and headache. However, the lesion may involve neighboring bony and neural structures, and may cause some unexpected findings, such as ptosis and 3rd cranial nerve paralysis, decreased vision, and proptosis. The patients also may reveal unusual presenting symptoms such as seizure, intracranial hemorrhage, and recurrent meningitis.6-20 Our present case revealed periauricular painful swelling due to the involvement of temporal bone and to the edema of neighboring soft tissues, headache secondary to the space occupying intracranial lesion and due to the involvement of dura, decreased hearing and facial nerve paralysis due to the involvement of 7th– 8th nerve complex by the tumoral mass, and pyramidal findings during the first admission secondary to the compression of brainstem. The ideal treatment is total resection of the lesion, and where needed, repair of the bony defect in an
FIG 3. (A) Axial fast spin-echo T2-weighted MRI (repetition time ms/echo time ms, 3200/112) shows the left-sided multi-loculated temporal lesion with a peripheral hypointense capsule and internal hypointense septations. The mass contains cystic cavities with smaller sizes than in previous pictures. The cavities are filled with heterogeneous fluid components, representing various stages of bleeding elements. (B) Coronal FLAIR MRI (repetition time ms/echo time ms/ inversion time ms, 6000/95/1800) reveals the extension of the lesion toward the intracranial direction, causing only mild compression on the neighboring temporal lobe. (C) Axial postgadolinium spin-echo T1-weighted MRI (repetition time ms/echo time ms, 430/15) shows intense contrast enhancement of the left temporal lesion, representing its more cellular components. Dural layer and peripheral capsule of the lesion on the cranial side are not clearly differentiated from each other.
Curr Probl Diagn Radiol, July/August 2003
173
appropriate manner. Preoperative angiography and embolization may make surgery easier in selected cases, because ABCs are highly vascular lesions and direct surgery can cause significant blood loss. Lesions involving the base of the skull present some problems in which thorough curettage and partial excision is the treatment of choice. There is a high recurrence rate even after thorough curettage. After subtotal excision, the recurrence rate is around 50%, and the rate after curettage is 20%. The recurrence rate is even higher if an associated lesion is present. Recurrence is rare if the dura is not involved. Residual and recurrent lesions usually respond to radiation therapy, with the inherent risks of postradiation sarcoma formation, for example. Radiation therapy should only be used in those cases that are not suitable for surgery. Although cryosurgery reduces recurrence rates after primary surgery and offers an alternative to radiation therapy, application in the skull has not yet been reported.2-5,15,16 Our present case revealed recurrence, with the formation of a more cellular or so-called solid variant of ABC, within 1 year after the subtotal excision of the lesion. Gross pathological studies reveal that ABCs are composed of multiple sinusoidal spaces filled with unclotted blood and blood-tinged serous fluid. These spaces are separated by fibrous or bony septa, giving a honeycomb appearance. Because the lesion originates within the diploic space of the bone, enlargement causes expansion of the diploic space, and the lesion is then surrounded by a thin shell of outer and inner skull tables. Histologically, ABCs are composed of honeycomb-like spaces without endothelial linings, and are filled with hemorrhagic fluid. The cysts are separated by septa composed of proliferated spindle-shaped fibroblasts with scattered multinucleated giant cells, hemosiderin-laden macrophages, granulation tissue, and extravasated red blood cells. The septa also usually contain trabeculae of new bone formation.2-5,15,21,24 The histopathological features of the surgical specimen from our present case were compatible with the above-mentioned characteristics of ABCs. Roentgenograms of the skull reveal aneurysmal bone cyst as a well-circumscribed expansile radiolucent lesion within the diploic space. The inner and outer tables of bone are thinned and separated from each other, giving the ballooning appearance of the so-called blow-out or soap-bubble pattern. The lytic lesion is surrounded by a thin marginal shell of sclerotic cortical bone. It may also contain thin internal trabeculations within the lesion.2-5,15,24
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Computed tomography shows an expanded diploic lesion that may be multiloculated, harboring areas of different density, sometimes with fluid–fluid levels. Both inner and outer bony tables are thinned, but their integrity is typically preserved. The peripheral capsule and internal septations of the lesion enhance strongly with intravenous administration of iodinated contrast materials.3,4,20,22 MRIs of ABCs reveal the characteristic appearance of the lesions. They are well-delineated expansile lesions surrounded by a fibrous capsule with hypointense signal intensity on all sequences. The lesions may have internal septations with hypointense signal intensity, separating multiple cystic components of the lesion. The cystic components are of heterogeneous signal intensities on all sequences, representing different stages of evolution of blood byproducts. The fluid–fluid levels within the cystic components are secondary to the layering of the uncoagulated blood; although this appearance is characteristic for ABCs, it is not specific, and may appear in other lytic bony lesions such as osteosarcoma, chondroblastoma, giant cell tumor, and malignant fibrous histiocytoma. MRIs may also visualize any occupation of the epidural space and brain compression in cases with an intracranial extension of the mass. Although they may expand intracranially in the orbital locations, they usually do not penetrate the dura. After intravenous gadolinium injection, the cystic lesions reveal intense contrast enhancement at the peripheral capsule and internal septations.2,4,15,22 Our present case revealed characteristic signal intensity and contrast-enhancement patterns of the lesion strongly suggestive for ABC on the initial presentation and follow-up MRIs of the temporal bone. The lesion also showed the focal cortical disruptions of both outer and inner tables of the temporal bone—not a common finding of ABCs, which are usually characterized by the preservation of both inner and outer tables of bone. The diagnosis of aneurysmal bone cyst can be strongly suspected by correlating the radiographic and MRI findings. However, for definitive diagnosis, accurate histopathological evaluation is imperative to rule out many lesions simulating ABCs, such as giant cell tumors, hemorrhagic cyst, enchondroma, metastases from renal cell ca and thyroid ca, plasmacytoma, chondrosarcoma, fibrosarcoma, fibrous dysplasia, hemophilic pseudotumor, and telangiectatic osteosarcoma.2,5,15,20
Curr Probl Diagn Radiol, July/August 2003
In conclusion, ABCs of the temporal bone are rare benign nonneoplastic lesions with well-known radiological features. These rare entities may cause local swelling of the bone and surrounding soft tissue, and may also cause neurological deficits, mostly secondary to the involvement of the 7th and 8th cranial nerves and to compression on the neighboring brain parenchyma. In this report, we presented a case of temporal ABC that was histologically confirmed, with characteristic MRI findings. Although some other lytic lesions may simulate the appearance of ABCs, and the definitive diagnosis is the histological examination of the surgical specimen, MRI should be considered as the first choice of diagnostic tool.
REFERENCES 1. Martinez V, Sissons HA. Aneurysmal bone cyst: a review of 123 cases including primary lesions and those secondary to other bone pathology. Cancer 1988;61:2291-304. 2. Cakirer S, Cakirer D, Kabukcuoglu F. Aneurysmal bone cyst of the orbit: a case of rare location and review of the literature. Clin Imaging 2002;26:386-91. 3. Guida F, Rapana A, Conti C, Cagliari E, Civelli F, Tricia G. Cranial aneurysmal bone cyst: a diagnostic problem. Child’s Nerv Syst 2001;17:297-301. 4. Sheikh BY. Cranial aneurysmal bone cyst with special emphasis on endovascular management. Acta Neurochir (Wien) 1999;141:601-11. 5. Kumar R, Mukherjee KK. Aneurysmal bone cyst of the skull: report of three cases. Br J Neurosurg 1999;13:82-4. 6. Chalapati Rao KV, Rao SB, Reddy PC, Sundareshwar B, Reddy CRRM. Aneurysmal bone cyst of the skull. J Neurosurg 1977;47:633-6. 7. Paige ML, Chiu YT Jr, Christ M. Aneurysmal bone cyst of the temporal bone. Neuroradiology 1979;18:161-4. 8. Keuskamp PA, Horoupian DS, Fein JM. Aneurysmal bone cyst of the temporal bone presenting as a spontaneous intracerebral hemorrhage: case report. Neurosurgery 1980;7:16670. 9. Mima S, Taguchi Y, Sekino H, Inomata I. Case of aneurysmal bone cyst of the skull. No Shinkei Geka 1984;12:825-31 (abstr).
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10. Calliauw L, Roels H, Caemaert J. Aneurysmal bone cysts in the cranial vault and base of skull. Surg Neurol 1985;23: 193-8. 11. Legent F, Lenne Y, Gayet M, et al. Aneurysmal cyst of the petrous bone. Apropos of a case. Ann Otolaryngol Chir Cervicofac 1988;105:591-6. 12. Lackmann GM, Tollner U. Aneurysmal bone cyst of the petrosal bone. Arch Dis Child 1993;69:241-2. 13. Wojno KJ, McCarthy EF. Fibro-osseous lesions of face and skull with aneurysmal bone cyst formation. Skeletal Radiol 1994;23:15-8. 14. Sawin PD, Muhonen MG, Sato Y, Smith RJ. Aneurysmal bone cyst of the temporal bone presenting as hearing loss in a child. Int J Pediatr Otorhinolaryngol 1995;33:275-84. 15. Shah GV, Doctor MR, Shah PS. Aneurysmal bone cyst of the temporal bone: MR findings. Am J Neuroradiol 1995;16: 763-6. 16. Shimizu T, Ukai K, Hayashi T, Imanishi Y, Sakakura Y. Aneurysmal bone cyst of the temporal bone: magnetic resonance imaging as a valuable tool for preoperative diagnosis. Am J Otolaryngol 1998;19:379-82. 17. Lippman CR, Jallo GI, Feghali JG, Jimenez E, Epstein F. Aneurysmal bone cyst of the temporal bone. Pediatr Neurosurg 1999;31:219-23. 18. Park AH, Phillips J, Forte V. Aneurysmal bone cyst of the temporal bone. Otolaryngol Head Neck Surg 1999;120:60610. 19. Ait Benali S, Ibahioin K, Zamiati S, et al. Sphenotemporal aneurysmal bone cyst. A new case and review of the literature. Neurochirurgie 2000;46:50-3 (abstr). 20. Chidambaram B, Santosh V, Balasubramaniam V. Aneurysmal bone cyst of the temporal bone. Childs Nerv Syst 2001;17:411-4. 21. Jaffe HL, Lichtenstein L. Solitary unicameral bone cyst with emphasis on the roentgen picture, the pathological appearance and the pathogenesis. Arch Surg 1942;44:1004-25. 22. Jansen J, Terwey B, Rama B, Markakis E. MRI diagnosis of aneurysmal bone cyst. Neurosurg Rev 1990;13:161-6. 23. Schonauer C, Tessitore E, Schonauer M. Aneurysmal bone cyst of the frontal bone in a soccer player. Acta Neurochir (Wien) 2000;142:1165-6. 24. Biesecker JL, Marcove RC, Huvos AG, Mike V. Aneurysmal bone cysts. A clinicopathological study of 66 cases. Cancer 1970;26:615-25.
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Aneurysmal Bone Cyst of the Temporal Bone Sinan Cakirer, MD, Muzaffer Basak, MD, Irfan Celebi, MD, Fevziye Kabukcuoglu, MD, and Yesim Erdem, MD
Aneurysmal bone cysts are benign fibrosseous lesions of the bone that are rarely detected in the temporal bone. Seventeen cases of aneurysmal bone cysts with histological confirmation involving the temporal bone were reported in the literature. We report a case of left temporal aneurysmal bone cyst in a 52-year-old male with the clinical findings of periauricular painful swelling, decreased hearing, and facial paralysis. A magnetic resonance image of the patient showed a well-circumscribed multi-loculated expansile lesion of the left temporal bone during the first admission to the hospital. The lesion recurred 1 year after the subtotal resection with a more solid appearance. In addition, we review the literature for these rare lesions.
Aneurysmal bone cysts (ABC) are benign, nonneoplastic, osteolytic, and expansile lesions of the bone. The most common locations for ABCs are the metaphyses of long bones, vertebrae, and flat bones. They are usually detected in patients in the first 2 to 3 decades of their lives.1 ABC of the skull is an unusual entity, and the reported incidence is around 2.5% to 6% of the cases.2-5 ABCs are very rarely found in the temporal bone; there are 17 cases with histological confirmation reported in the literature.6-20 We present a case of ABC of the temporal bone that revealed characteristic magnetic resonance imaging (MRI) findings, and recurred after the subtotal resection of the lesion with a more solid MRI and histological appearance. We also review all of the available cases with histological
From the Department of Radiology; and the Department of Pathology, Istanbul Sisli Etfal Hospital, Istanbul, Turkey Reprint requests: Sinan Cakirer, 67 Ada, Kardelen 4/2, Daire 37, 81120 Ataþehir, Istanbul, Turkey. E-mail: [email protected]. Curr Probl Diagn Radiol 2003;32:169-175. © 2003 Mosby, Inc. All rights reserved. 0363-0188/2003/$30.00 ⫹ 0 doi:10.1016/S0363-0188(03)00025-2
Curr Probl Diagn Radiol, July/August 2003
confirmation of ABCs involving the temporal bone (Table 1). The final diagnosis is the histological examination of a surgical specimen; however, preoperative MRI study of the patient should be performed both to differentiate ABC from other lytic lesions and to determine a surgical strategy for the lesion.
Case Description A 52-year-old man presented with a left-sided painful preauricular swelling, severe headache, decreased hearing, and facial asymmetry, developing over a period of approximately 6 months. The neurological examination of the patient detected severe sensorineural hearing loss and facial paralysis on the left side, and bilateral papilledema and mild pyramidal findings on the right side. A cranial MRI study was performed in three orthogonal planes with a standard head coil on a 1.5-T MR scanner (Picker Eclipse, Picker International, Cincinnati, OH). Spin-echo (SE) T1-weighted images (repetition time ms/echo time ms, 430/15), fast spin echo (FSE), proton-density (PD), and T2weighted images (repetition time ms/echo time ms, 3200/30 and 3200/112) in the axial plane, FLAIR images (repetition time ms/echo time ms/inversion time ms, 6000/95/1800) in the coronal plane, and SE T1-weighted images (repetition time ms/echo time ms, 330/15) in the sagittal plane were obtained. Spin-echo T1-weighted sequences were repeated in three planes after intravenous administration of gadopentetate dimeglumine (Magnevist; Schering, Berlin, Germany) at a dose of 0.15 mL/kg. Slice thickness and interval values were 5 mm and 2 mm, respectively, for the whole examination protocol. MRI of the patient revealed a well-circumscribed multi-loculated lesion that originated from the left
169
TABLE 1. Cases of histologically proven aneurysmal bone cysts involving the temporal bone, reported between 1970 –2002 in the literature No. Year/ref Age/sex Clinical findings Location Histology Treatment Result 1
19776
14 year/M
Enlarging head swelling, headache, neck pain
2
19797
16 year/F
3
19808
62 year/M
4
19849
36 year/M
5
198510
36 year/M
6
198510
19 year/F
7
198811
23 year/F
8
199312
8 year/M
Headache, enlarging mass Sudden loss of consciousness, 3rd nerve palsy Decreased hearing, transient impairment of vision, facial weakness Seizure, deafness, 7th nerve palsy, 5th nerve sensory loss Headache, exophthalmos, diplopia Otalgia, severe endolabyrinthic- type perception deafness Recurrent meningitis
9
199413
14 year/F
10
199413
11
R Temporooccipital LT
ABC
ABC
Aspiration biopsy, then total resection Total resection
LT
ABC
Total resection
RT
ABC
Total resection
Unknown
LT
ABC
Total resection
Recurrence free for 2.5 years
LT
ABC
Total resection
RT-O
ABC
Curettage
Recurrence free for 1.5 years Unknown
RT
ABC
Total resection
Painless facial swelling
RT
Total resection
22 year/M
Ptosis,decreased vision
LT
Fibrous dysplasia with ABC FD with ABC
199514
10 year/F
RT
ABC
Total resection
12
199515
28 year/M
LT
ABC
Radiotherapy and excision
Unknown
13 14
199816 199917
13 year/M 9 year/M
Progressive hearing loss, headache, stenotic external auditory canal Painful swelling behind left ear, headache, decreased hearing Facial swelling Posterior auricular pain
LT LT
ABC ABC
Total resection Total resection
15 16
199918 200019
15 year/M 5 year/F
ABC ABC
Total resection Total resection
17
200120
5.5 year/M
RT RTsphenoid RT
AC
Total resection
18
Present case
52 year/M
LT
ABC
Subtotal resection
Unknown Recurrence free for several weeks Unknown Recurrence free for 27 months Recurrence free for several months Recurrence 1 year after surgery
Decreased hearing Posterior auricular tough and fixed swelling Proptosis, temporal swelling Decreased hearing, facial paralysis, periauricular pain and swelling
Total resection
Unknown
Recurrence free for 1.5 years Recurrence free for 2 months
Recurrence free for 1 month Recurrence free for 2 years Recurrence free for 1 year Recurrence free for 6 weeks
(Ref: reference no, M: male, F: female, R: right, L: left, T: temporal, ABC: aneurysmal bone cyst).
temporal bone. The cystic mass caused expansion of the diploic space of the temporal bone, with thinning and some focal disruptions of external and internal tables. The lesion contained a thin peripheral capsule and thin internal septations that revealed hypointense signal-intensity characteristics on all sequences, and intense contrast enhancement after intravenous gadolinium administration. The internal septa separated multiple cystic cavities of variegated signal intensities. The lesion was detected to extend toward the intracranial direction, and caused a prominent compression on the neighboring temporal lobe, and indirectly on the
170
frontobasal lobe and left cerebral peduncle. The mass caused the effacement of left sylvian cistern and left-sided lateral ventricle compartments, as well as an additional contralateral subfalcian shift of the midline structures. The mass showed an epidural extension; the dural layer and peripheral capsule of the lesion on the cranial side were not clearly differentiated from each other on MRI pictures, and they enhanced strongly with intravenous gadolinium administration. The mass also showed some degree of extracranial extension associated with the edema of overlying temporalis muscle and scalp (Fig 1). MRI of the
Curr Probl Diagn Radiol, July/August 2003
patient was strongly suggestive for a radiological diagnosis of aneurysmal bone cyst of the temporal bone. The lesion was subtotally resected until the dura was reached; the dura was infiltrated with the mass extending beyond the fibrous capsule medially. The histological examination of the specimen showed a highly vascular lesion composed of numerous bloodfilled sinusoidal spaces without endothelial linings, separated by multiple septations. The fibrous capsule and septations contained multiple spindle-shaped fibroblasts and some multinucleated giant cells, hemosiderin-laden macrophages, and extravasated red blood cells. New bone formation was also evident within some septations (Fig 2). The histological diagnosis was consistent with the aneurysmal bone cyst of the temporal bone. Left-sided preauricular painful swelling and rightsided mild pyramidal findings promptly regressed within 1 month and the patient’s headache almost disappeared in 6 weeks, but the degree of hearing loss and facial paralysis did not change considerably. The patient complained of severe headache and periauricular painful swelling almost 1 year after the surgical therapy. A control cranial MRI study was repeated on the same MRI scanner with the same technical parameters and protocol. A lesion was detected in the temporal bone— but with a lower location than the previous one—that had a peripheral thin capsule and multiple thin septations separating multiple minute cyst-like cavities. The cyst-like cavities were filled with an intense material. The fibrous capsule and internal septations revealed intense contrast enhancement after intravenous gadolinium administration. The
FIG 1. (A) Axial fast spin-echo T2-weighted MRI (repetition time ms/echo time ms, 3200/112) shows a well-circumscribed left-sided multi-cystic temporal lesion with a peripheral hypointense capsule and internal hypointense septations. The cystic mass causes expansion of the diploic space of the temporal bone, with thinning of external and internal tables. The cavities are filled with hyperintense fluid. (B) Coronal FLAIR MRI (repetition time ms/echo time ms/inversion time ms, 6000/95/1800) reveals the extension of lesion toward the intracranial direction, causing a prominent compression on the neighboring temporal lobe. The mass causes the effacement of left sylvian cistern and left-sided lateral ventricle compartments, and an additional contralateral subfalcian shift of the midline structures. (C) Axial postgadolinium spin-echo T1-weighted MRI (repetition time ms/echo time ms, 430/15) shows intense contrast enhancement of the left temporal lesion at its periphery and internal septations. Dural layer and peripheral capsule of the lesion on the cranial side are not clearly differentiated from each other. The mass shows some degree of extracranial extension associated with the edema of overlying temporalis muscle and scalp as well.
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FIG 2. (A) Microphotograph of the surgical specimen shows cystic spaces containing red blood cells, which are separated by septa composed of spindle-shaped fibroblastic cells and some scattered multinucleated giant cells (hematoxylin-eosin stain; original magnification, ⫻100). (B) The septum contains areas of reactive osteoid formation with some scattered multinucleated giant cells, and cystic spaces contain plenty of red blood cells (hematoxylin-eosin stain; original magnification, ⫻200).
neighboring dural layers were infiltrated with the outer margin of the lesion. The mass caused some compression on the neighboring temporal lobe; however, the frontal lobe, brainstem, and lateral ventricles were all free of compression, except for mild effacement of left sylvian fissure. The mass extended toward infratemporal fossa as well. The lesion showed some extracranial extension associated with the edema of overlying temporalis muscle and scalp (Fig 3). MRI suggested the recurrence of the aneurysmal bone cyst of temporal bone. A second surgical operation was planned after the excisional biopsy of lesion, which confirmed the diagnosis of ABC with a more cellular histological appearance that was accepted as a solid variant of ABC.
Discussion In 1942, Jaffe and Lichtenstein coined the term “aneurysmal bone cyst” to identify a peculiar entity: an expanding bony lesion with a vascular lining and a characteristic radiological appearance of a soap bubble.21 ABCs are benign, but expansile and locally aggressive lesions of the bone, containing thin-walled blood-filled cystic cavities that are lined by connective tissue with giant cells and trabecular bone. ABCs represent 6% of the bone tumors. They are most commonly found in the shafts of the long bones with eccentrical metaphyseal location, and the posterior elements of the vertebrae. Only 2.5% to 6% of the
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lesions arise from the bones of skull.1-5,21,22 Temporal ABCs are very rare entities, reported in only 17 cases in the English literature.6-20 Approximately 75% to 90% of the ABCs occur in patients younger than 20 years of age.2,4,5 Most of the reports, including the paper for ABCs of the skull by Sheikh, showed no sex predominance for ABCs.4 From the collected 17 cases involving the temporal bone, 6 patients were female and 11 patients were male. This finding shows that ABCs of the temporal bone have a predilection for the male sex. The ages of patients, excluding our present case, ranged from 5 years to 62 years, with a mean age of 19.4 years.6-20 Most experiences with ABCs have been obtained from the lesions located in the long bones and vertebrae. They may be primary or secondary. Although some theories have been proposed, the exact cause of primary ABCs is not yet clear. The development of focal dynamic alterations with secondary venous hypertension may cause a slow expansion of the cortex, according to Lichtenstein. A history of local trauma has been reported before the development of ABCs in some other papers; however, in many cases there has been no history of trauma. The view that there is a basic underlying arteriovenous anomaly resulting in dilated vascular spaces seems to provide a good explanation for the histological features and clinical course of ABCs.15,20,23,24 In the long bones, nearly one third of the lesions are considered secondary to the
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preexisting bone lesions; recently, a similar association has been observed in ABCs of the skull as well. Secondary ABCs arise from pre-existing bone lesions such as giant cell tumor, osteoblastoma, chondroblastoma, nonossifying fibroma, angioma, fibrous dysplasia, unicameral bone cyst, and chondromyxoid fibroma.1,3,4,15 A similar association is present in two cases of ABC of the temporal bone with a medical history of fibrous dysplasia involving the temporal region.13 However, our present case did not have any associated pre-existing lesion of that area, nor a history of trauma, so he was accepted to have a primary ABC of the temporal bone. Clinical findings of temporal ABCs are related to the presence and location of the mass lesion. The most common mode of presentation for temporal ABCs is the swelling around the temporal region that may or may not be associated with pain. Other presenting symptoms are decreased hearing, 5th and 7th cranial nerve paralyzes and headache. However, the lesion may involve neighboring bony and neural structures, and may cause some unexpected findings, such as ptosis and 3rd cranial nerve paralysis, decreased vision, and proptosis. The patients also may reveal unusual presenting symptoms such as seizure, intracranial hemorrhage, and recurrent meningitis.6-20 Our present case revealed periauricular painful swelling due to the involvement of temporal bone and to the edema of neighboring soft tissues, headache secondary to the space occupying intracranial lesion and due to the involvement of dura, decreased hearing and facial nerve paralysis due to the involvement of 7th– 8th nerve complex by the tumoral mass, and pyramidal findings during the first admission secondary to the compression of brainstem. The ideal treatment is total resection of the lesion, and where needed, repair of the bony defect in an
FIG 3. (A) Axial fast spin-echo T2-weighted MRI (repetition time ms/echo time ms, 3200/112) shows the left-sided multi-loculated temporal lesion with a peripheral hypointense capsule and internal hypointense septations. The mass contains cystic cavities with smaller sizes than in previous pictures. The cavities are filled with heterogeneous fluid components, representing various stages of bleeding elements. (B) Coronal FLAIR MRI (repetition time ms/echo time ms/ inversion time ms, 6000/95/1800) reveals the extension of the lesion toward the intracranial direction, causing only mild compression on the neighboring temporal lobe. (C) Axial postgadolinium spin-echo T1-weighted MRI (repetition time ms/echo time ms, 430/15) shows intense contrast enhancement of the left temporal lesion, representing its more cellular components. Dural layer and peripheral capsule of the lesion on the cranial side are not clearly differentiated from each other.
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appropriate manner. Preoperative angiography and embolization may make surgery easier in selected cases, because ABCs are highly vascular lesions and direct surgery can cause significant blood loss. Lesions involving the base of the skull present some problems in which thorough curettage and partial excision is the treatment of choice. There is a high recurrence rate even after thorough curettage. After subtotal excision, the recurrence rate is around 50%, and the rate after curettage is 20%. The recurrence rate is even higher if an associated lesion is present. Recurrence is rare if the dura is not involved. Residual and recurrent lesions usually respond to radiation therapy, with the inherent risks of postradiation sarcoma formation, for example. Radiation therapy should only be used in those cases that are not suitable for surgery. Although cryosurgery reduces recurrence rates after primary surgery and offers an alternative to radiation therapy, application in the skull has not yet been reported.2-5,15,16 Our present case revealed recurrence, with the formation of a more cellular or so-called solid variant of ABC, within 1 year after the subtotal excision of the lesion. Gross pathological studies reveal that ABCs are composed of multiple sinusoidal spaces filled with unclotted blood and blood-tinged serous fluid. These spaces are separated by fibrous or bony septa, giving a honeycomb appearance. Because the lesion originates within the diploic space of the bone, enlargement causes expansion of the diploic space, and the lesion is then surrounded by a thin shell of outer and inner skull tables. Histologically, ABCs are composed of honeycomb-like spaces without endothelial linings, and are filled with hemorrhagic fluid. The cysts are separated by septa composed of proliferated spindle-shaped fibroblasts with scattered multinucleated giant cells, hemosiderin-laden macrophages, granulation tissue, and extravasated red blood cells. The septa also usually contain trabeculae of new bone formation.2-5,15,21,24 The histopathological features of the surgical specimen from our present case were compatible with the above-mentioned characteristics of ABCs. Roentgenograms of the skull reveal aneurysmal bone cyst as a well-circumscribed expansile radiolucent lesion within the diploic space. The inner and outer tables of bone are thinned and separated from each other, giving the ballooning appearance of the so-called blow-out or soap-bubble pattern. The lytic lesion is surrounded by a thin marginal shell of sclerotic cortical bone. It may also contain thin internal trabeculations within the lesion.2-5,15,24
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Computed tomography shows an expanded diploic lesion that may be multiloculated, harboring areas of different density, sometimes with fluid–fluid levels. Both inner and outer bony tables are thinned, but their integrity is typically preserved. The peripheral capsule and internal septations of the lesion enhance strongly with intravenous administration of iodinated contrast materials.3,4,20,22 MRIs of ABCs reveal the characteristic appearance of the lesions. They are well-delineated expansile lesions surrounded by a fibrous capsule with hypointense signal intensity on all sequences. The lesions may have internal septations with hypointense signal intensity, separating multiple cystic components of the lesion. The cystic components are of heterogeneous signal intensities on all sequences, representing different stages of evolution of blood byproducts. The fluid–fluid levels within the cystic components are secondary to the layering of the uncoagulated blood; although this appearance is characteristic for ABCs, it is not specific, and may appear in other lytic bony lesions such as osteosarcoma, chondroblastoma, giant cell tumor, and malignant fibrous histiocytoma. MRIs may also visualize any occupation of the epidural space and brain compression in cases with an intracranial extension of the mass. Although they may expand intracranially in the orbital locations, they usually do not penetrate the dura. After intravenous gadolinium injection, the cystic lesions reveal intense contrast enhancement at the peripheral capsule and internal septations.2,4,15,22 Our present case revealed characteristic signal intensity and contrast-enhancement patterns of the lesion strongly suggestive for ABC on the initial presentation and follow-up MRIs of the temporal bone. The lesion also showed the focal cortical disruptions of both outer and inner tables of the temporal bone—not a common finding of ABCs, which are usually characterized by the preservation of both inner and outer tables of bone. The diagnosis of aneurysmal bone cyst can be strongly suspected by correlating the radiographic and MRI findings. However, for definitive diagnosis, accurate histopathological evaluation is imperative to rule out many lesions simulating ABCs, such as giant cell tumors, hemorrhagic cyst, enchondroma, metastases from renal cell ca and thyroid ca, plasmacytoma, chondrosarcoma, fibrosarcoma, fibrous dysplasia, hemophilic pseudotumor, and telangiectatic osteosarcoma.2,5,15,20
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In conclusion, ABCs of the temporal bone are rare benign nonneoplastic lesions with well-known radiological features. These rare entities may cause local swelling of the bone and surrounding soft tissue, and may also cause neurological deficits, mostly secondary to the involvement of the 7th and 8th cranial nerves and to compression on the neighboring brain parenchyma. In this report, we presented a case of temporal ABC that was histologically confirmed, with characteristic MRI findings. Although some other lytic lesions may simulate the appearance of ABCs, and the definitive diagnosis is the histological examination of the surgical specimen, MRI should be considered as the first choice of diagnostic tool.
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