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Anterior cranial fossa dermoid cyst: Case report
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British Journal of Oral and Maxillofacial Surgery 45 (2007) 661–663
Short communication
Anterior cranial fossa dermoid cyst: Case report J.N.St.J. Blythe a,∗ , P.J. Revington a , R. Nelson b a b
Department of Oral and Maxillofacial Surgery, Frenchay Hospital, Bristol BS16 1LE, UK Department of Neurosurgery, Frenchay Hospital, Bristol BS16 1LE, UK
Accepted 31 August 2006 Available online 24 October 2006
Abstract We report a case of an intracranial mass that presented with proptosis and diplopia, and proved to be a dermoid cyst. Resection was successful and there had been no recurrence after 5 years. © 2006 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Anterior cranial fossa; Dermoid cyst; Space-occupying lesion; Proptosis
Introduction
Case report
There are three types of benign cyst that can have a spaceoccupying effect in the cranial cavity: arachidonic, epidermoid, and dermoid. A dermoid cyst situated in the anterior cranial fossa is rare. Such cysts have thick walls and may connect to the skin surface through a bony defect. Most dermoid cysts appear on a computed tomogram (CT) as lowdensity masses, while magnetic resonance imaging (MRI) may record varying signal characteristics caused by the relative proportions of lipid, keratin, soft tissue, and water within the cyst. Neurological complications arise from the effect of the mass or spontaneous rupture into the subarachnoid space, which can precipitate seizures or a chemical meningitis syndrome. Complete excision without rupture is the gold standard, but tough adherence of the cystic wall within the cranium may cause rupture and incomplete excision of the cyst, predisposing to both recurrence and neurological complications.1,2
A 46-year-old white man was referred to the maxillofacial department with pronounced proptosis of the right eye and intermittent diplopia. His history included a bloodshot right eye, blurred vision, and asymmetrical eyes. His medical history was unremarkable. Physical examination showed an irregular right frontozygomatic margin and “fullness” over the frontal bone laterally. The ophthalmic examination showed 5 mm of proptosis, full eye movements, and normal visual fields. The remaining head, neck, and cranial nerves were unremarkable. CT and MRI showed a large (Figs. 1 and 2), relatively well defined, low-density extradural mass in the inferior aspect of the right anterior cranial fossa that extended into the right orbit. The mass had eroded through part of the greater wing of the sphenoid, and the roof and lateral wall of the orbit. The differential diagnosis included lacrimal gland neoplasm, dermoid cyst, primary bone neoplasm, or meningioma. Under general anaesthesia a bi-coronal flap was raised to expose a small lateral frontal defect. The lining of the cyst was dissected free around the existing defect and a predrilled frontal bone flap was removed to give access to the anterior cranial fossa and the orbit. The capsule of the cyst, which ruptured during the operation, was dissected free from the adjacent dura. The orbital roof was absent, but a dense
∗ Corresponding author at: St. Bartholomew’s and The Royal London School of Medicine and Dentistry, Dawson Hall, Charterhouse Square, London EC1M 6BQ, UK. Tel: +44 1865 794130. E-mail address: [email protected] (J.N.St.J. Blythe).
0266-4356/$ – see front matter © 2006 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.bjoms.2006.08.020
662
J.N.St.J. Blythe et al. / British Journal of Oral and Maxillofacial Surgery 45 (2007) 661–663
Fig. 1. Axial computed tomogram of orbits showing extent of proptosis.
fibroperiosteal membrane separated the orbit from the anterior cranial fossa. Formal reconstruction of this region was not required. The predrilled bone flap was replaced and fixed with AO miniplates and 1 mm screws. The skin was closed with staples, and two Redivac drains were placed in the scalp wound, remote from the bone flap. There were no postoperative complications and the patient was discharged 4 days later, with no diplopia or proptosis. The histopathological report confirmed the diagnosis. He was reviewed 2 weeks and 1 month postoperatively, and no abnormality was found. The patient had a follow up MRI 1 year after operation, which showed some ill-defined soft tissue within the roof of the right orbit, and extending through the defect in the skull,
Fig. 3. Five-year postoperative magnetic resonance image showing no signs of recurrence of the dermoid cyst.
probably abutting the dura that did not respond to injection of contrast. At the 5-year follow up in 2004 he complained again of blurred vision. The subsequent ophthalmological assessment identified 2 mm of hypoglobus and a swollen right optic disc that suggested compressive optic neuropathy. The fundal changes were interpreted as indicating an old occlusion of the superior branch of the ophthalmic vein. It is uncertain to what extent these changes are attributable to his previous operation. His eyesight has, however, improved since he was prescribed new glasses. The 5-year postoperative MRI (Fig. 3) shows no sign of recurrence.
Discussion
Fig. 2. Initial coronal magnetic resonance image of the orbit. Heterogeneous expansile mass arising from the supralateral aspect of the right orbit. Local bony destruction: orbital roof, floor of right anterior cranial fossa, and inferior frontal bone. Main lesion abuts right frontal lobe and extraocular muscle complex without obvious invasion.
Dermoid cysts develop mainly from epithelium caught within lines of embryonic fusion. Presentation is bimodal; they are either discovered during the first few years of life or within the third and fourth decades. Forty percent are clinically discernible at birth, which rises to 70% by the age of five, with a female preponderance. They are most prevalent in the craniofacial region and neck: periorbital, bridge of nose, scalp, floor of mouth, and anterior neck. Dermoid cysts account for 24% of all orbital masses.3 There are a number of hypotheses about their origin. One is that they start to form during the fourth week of gestation, during neurulation, as a result of breaches arising in the moving tides of neuroectoderm and over-arching ectoderm, which can cause fistulas to form between the skin and the brain or spinal cord, which have the potential to expand into cysts internally, externally, or both. A further hypothesis is that fragments of ectoderm are pinched and sequestered during embryogenesis along the osseous fusion lines.2
J.N.St.J. Blythe et al. / British Journal of Oral and Maxillofacial Surgery 45 (2007) 661–663
Dermoid cysts are located superficially to, or deep within, the subcutaneous tissue, with a tendency to attach to periosteum; they are rarely intracranial or intraspinal. They have the ability to invade bone. They are lined by keratinised squamous epithelium, hair follicles, sebaceous glands, sweat glands, and (rarely) teeth. The contents of the lumen include lipid, keratin, and hair. The natural history is of slow growth, expanding into a mass. Inflammatory episodes are possible. The bimodal presentation correlates with the depth of the cyst, with “deeply” buried presenting only when there has been considerable destruction of soft and hard tissues. In the orbital region typical features are globe dystopia, proptosis, and visual abnormalities.1 Bony destruction is rare in children except for mild concavities in the underlying bone; bony defects are more common in adults, when such cysts are characteristically shaped like an hourglass. Most dermoid cysts are asymptomatic, but they can cause recurrent infections. Complications include osteomyelitis, meningitis, pressure, erosion, and visual disturbances. CT or MRI are essential in diagnosis, planning treatment, and monitoring possible recurrence. The treatment of choice is complete excision. In our case the bi-coronal approach was thought to offer both the best access to the area and the best cosmetic result for the patient, the alternative being a hemicoronal flap. Complete excision is difficult, and several studies have shown that dermoid cysts can encapsulate or adhere to intracranial vessels.4 The rupturing of dermoid cysts can lead to multiple complications, which include headaches, seizures, meningitis, arachnoiditis, ventriculitis, hydrocephalus, acute hemiparesis, and cheiro-oral syndrome.5–10 These arise as a consequence of spillage of contents through the dura mater.
663
More recently, a delayed ischaemic deficit has been reported, caused possibly by lipid metabolites and hyperkalaemia leaking from the lumen of the cyst and stimulating vasospasm.5 No postoperative complications were noted in this case. References 1. Rook A, Wilkinson DS, Ebling FJG, Champion RH, Burton JL, editors. Textbook of dermatology, vol. 3, 4th ed. London: Blackwell; 2001. p. 221–2. 2. Larsen W. In: Sherman L, Potter S, Scott W, editors. Human embryology. 3rd ed. Edinburgh: Churchill Livingstone; 1998. p. 351–417. 3. Shields JA, Bakewell JB, Ausburger JS, Flanagan JC. Classification and incidence of space occupying lesions of the orbit. Arch Ophthalmol 1984;102:1606–11. 4. Ecker RD, Atkinson JL, Nichols DA. Delayed ischemic deficit after resection of a large intracranial dermoid: case report and review of the literature. Neurosurgery 2003;52:706–10. 5. Abramson RC, Mrawetz RB, Schlitt M. Multiple complications from an intracranial epidermoid. Case report and literature review. Neurosurgery 1989;24:574–8. 6. Bucciero A, De Caro ML, Tedeschi E, Vizioli L, Cerillo A, Tedeschi G. Supratentorial dermoid cysts: presentation and management of five cases. J Neurosurg Sci 1995;39:7–11. 7. Currarino G, Rutledge JC. Temporoparietal dermoid cysts with intracranial extension. Am J Neuroradiol 1988;9:385–7. 8. Lunardi P, Missori P, Rizzo A, Gagliardi FM. Chemical meningitis in ruptured intraranial dermoid. Case report and review of the literature. Surg Neurol 1989;32:449–52. 9. Roeder MB, Bazan C, Jinkins JR. Ruptured spinal dermoid cyst with chemical arachnoiditis and disseminated intracranial lipid droplets. Neuroradiology 1995;37:146–7. 10. Yasargil MG, Abernathey CD, Sarioglu AC. Microneurosurgical treatment of intracranial dermoid and epidermoid tumours. Neurosurgery 1989;24:561–7.
British Journal of Oral and Maxillofacial Surgery 45 (2007) 661–663
Short communication
Anterior cranial fossa dermoid cyst: Case report J.N.St.J. Blythe a,∗ , P.J. Revington a , R. Nelson b a b
Department of Oral and Maxillofacial Surgery, Frenchay Hospital, Bristol BS16 1LE, UK Department of Neurosurgery, Frenchay Hospital, Bristol BS16 1LE, UK
Accepted 31 August 2006 Available online 24 October 2006
Abstract We report a case of an intracranial mass that presented with proptosis and diplopia, and proved to be a dermoid cyst. Resection was successful and there had been no recurrence after 5 years. © 2006 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Anterior cranial fossa; Dermoid cyst; Space-occupying lesion; Proptosis
Introduction
Case report
There are three types of benign cyst that can have a spaceoccupying effect in the cranial cavity: arachidonic, epidermoid, and dermoid. A dermoid cyst situated in the anterior cranial fossa is rare. Such cysts have thick walls and may connect to the skin surface through a bony defect. Most dermoid cysts appear on a computed tomogram (CT) as lowdensity masses, while magnetic resonance imaging (MRI) may record varying signal characteristics caused by the relative proportions of lipid, keratin, soft tissue, and water within the cyst. Neurological complications arise from the effect of the mass or spontaneous rupture into the subarachnoid space, which can precipitate seizures or a chemical meningitis syndrome. Complete excision without rupture is the gold standard, but tough adherence of the cystic wall within the cranium may cause rupture and incomplete excision of the cyst, predisposing to both recurrence and neurological complications.1,2
A 46-year-old white man was referred to the maxillofacial department with pronounced proptosis of the right eye and intermittent diplopia. His history included a bloodshot right eye, blurred vision, and asymmetrical eyes. His medical history was unremarkable. Physical examination showed an irregular right frontozygomatic margin and “fullness” over the frontal bone laterally. The ophthalmic examination showed 5 mm of proptosis, full eye movements, and normal visual fields. The remaining head, neck, and cranial nerves were unremarkable. CT and MRI showed a large (Figs. 1 and 2), relatively well defined, low-density extradural mass in the inferior aspect of the right anterior cranial fossa that extended into the right orbit. The mass had eroded through part of the greater wing of the sphenoid, and the roof and lateral wall of the orbit. The differential diagnosis included lacrimal gland neoplasm, dermoid cyst, primary bone neoplasm, or meningioma. Under general anaesthesia a bi-coronal flap was raised to expose a small lateral frontal defect. The lining of the cyst was dissected free around the existing defect and a predrilled frontal bone flap was removed to give access to the anterior cranial fossa and the orbit. The capsule of the cyst, which ruptured during the operation, was dissected free from the adjacent dura. The orbital roof was absent, but a dense
∗ Corresponding author at: St. Bartholomew’s and The Royal London School of Medicine and Dentistry, Dawson Hall, Charterhouse Square, London EC1M 6BQ, UK. Tel: +44 1865 794130. E-mail address: [email protected] (J.N.St.J. Blythe).
0266-4356/$ – see front matter © 2006 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.bjoms.2006.08.020
662
J.N.St.J. Blythe et al. / British Journal of Oral and Maxillofacial Surgery 45 (2007) 661–663
Fig. 1. Axial computed tomogram of orbits showing extent of proptosis.
fibroperiosteal membrane separated the orbit from the anterior cranial fossa. Formal reconstruction of this region was not required. The predrilled bone flap was replaced and fixed with AO miniplates and 1 mm screws. The skin was closed with staples, and two Redivac drains were placed in the scalp wound, remote from the bone flap. There were no postoperative complications and the patient was discharged 4 days later, with no diplopia or proptosis. The histopathological report confirmed the diagnosis. He was reviewed 2 weeks and 1 month postoperatively, and no abnormality was found. The patient had a follow up MRI 1 year after operation, which showed some ill-defined soft tissue within the roof of the right orbit, and extending through the defect in the skull,
Fig. 3. Five-year postoperative magnetic resonance image showing no signs of recurrence of the dermoid cyst.
probably abutting the dura that did not respond to injection of contrast. At the 5-year follow up in 2004 he complained again of blurred vision. The subsequent ophthalmological assessment identified 2 mm of hypoglobus and a swollen right optic disc that suggested compressive optic neuropathy. The fundal changes were interpreted as indicating an old occlusion of the superior branch of the ophthalmic vein. It is uncertain to what extent these changes are attributable to his previous operation. His eyesight has, however, improved since he was prescribed new glasses. The 5-year postoperative MRI (Fig. 3) shows no sign of recurrence.
Discussion
Fig. 2. Initial coronal magnetic resonance image of the orbit. Heterogeneous expansile mass arising from the supralateral aspect of the right orbit. Local bony destruction: orbital roof, floor of right anterior cranial fossa, and inferior frontal bone. Main lesion abuts right frontal lobe and extraocular muscle complex without obvious invasion.
Dermoid cysts develop mainly from epithelium caught within lines of embryonic fusion. Presentation is bimodal; they are either discovered during the first few years of life or within the third and fourth decades. Forty percent are clinically discernible at birth, which rises to 70% by the age of five, with a female preponderance. They are most prevalent in the craniofacial region and neck: periorbital, bridge of nose, scalp, floor of mouth, and anterior neck. Dermoid cysts account for 24% of all orbital masses.3 There are a number of hypotheses about their origin. One is that they start to form during the fourth week of gestation, during neurulation, as a result of breaches arising in the moving tides of neuroectoderm and over-arching ectoderm, which can cause fistulas to form between the skin and the brain or spinal cord, which have the potential to expand into cysts internally, externally, or both. A further hypothesis is that fragments of ectoderm are pinched and sequestered during embryogenesis along the osseous fusion lines.2
J.N.St.J. Blythe et al. / British Journal of Oral and Maxillofacial Surgery 45 (2007) 661–663
Dermoid cysts are located superficially to, or deep within, the subcutaneous tissue, with a tendency to attach to periosteum; they are rarely intracranial or intraspinal. They have the ability to invade bone. They are lined by keratinised squamous epithelium, hair follicles, sebaceous glands, sweat glands, and (rarely) teeth. The contents of the lumen include lipid, keratin, and hair. The natural history is of slow growth, expanding into a mass. Inflammatory episodes are possible. The bimodal presentation correlates with the depth of the cyst, with “deeply” buried presenting only when there has been considerable destruction of soft and hard tissues. In the orbital region typical features are globe dystopia, proptosis, and visual abnormalities.1 Bony destruction is rare in children except for mild concavities in the underlying bone; bony defects are more common in adults, when such cysts are characteristically shaped like an hourglass. Most dermoid cysts are asymptomatic, but they can cause recurrent infections. Complications include osteomyelitis, meningitis, pressure, erosion, and visual disturbances. CT or MRI are essential in diagnosis, planning treatment, and monitoring possible recurrence. The treatment of choice is complete excision. In our case the bi-coronal approach was thought to offer both the best access to the area and the best cosmetic result for the patient, the alternative being a hemicoronal flap. Complete excision is difficult, and several studies have shown that dermoid cysts can encapsulate or adhere to intracranial vessels.4 The rupturing of dermoid cysts can lead to multiple complications, which include headaches, seizures, meningitis, arachnoiditis, ventriculitis, hydrocephalus, acute hemiparesis, and cheiro-oral syndrome.5–10 These arise as a consequence of spillage of contents through the dura mater.
663
More recently, a delayed ischaemic deficit has been reported, caused possibly by lipid metabolites and hyperkalaemia leaking from the lumen of the cyst and stimulating vasospasm.5 No postoperative complications were noted in this case. References 1. Rook A, Wilkinson DS, Ebling FJG, Champion RH, Burton JL, editors. Textbook of dermatology, vol. 3, 4th ed. London: Blackwell; 2001. p. 221–2. 2. Larsen W. In: Sherman L, Potter S, Scott W, editors. Human embryology. 3rd ed. Edinburgh: Churchill Livingstone; 1998. p. 351–417. 3. Shields JA, Bakewell JB, Ausburger JS, Flanagan JC. Classification and incidence of space occupying lesions of the orbit. Arch Ophthalmol 1984;102:1606–11. 4. Ecker RD, Atkinson JL, Nichols DA. Delayed ischemic deficit after resection of a large intracranial dermoid: case report and review of the literature. Neurosurgery 2003;52:706–10. 5. Abramson RC, Mrawetz RB, Schlitt M. Multiple complications from an intracranial epidermoid. Case report and literature review. Neurosurgery 1989;24:574–8. 6. Bucciero A, De Caro ML, Tedeschi E, Vizioli L, Cerillo A, Tedeschi G. Supratentorial dermoid cysts: presentation and management of five cases. J Neurosurg Sci 1995;39:7–11. 7. Currarino G, Rutledge JC. Temporoparietal dermoid cysts with intracranial extension. Am J Neuroradiol 1988;9:385–7. 8. Lunardi P, Missori P, Rizzo A, Gagliardi FM. Chemical meningitis in ruptured intraranial dermoid. Case report and review of the literature. Surg Neurol 1989;32:449–52. 9. Roeder MB, Bazan C, Jinkins JR. Ruptured spinal dermoid cyst with chemical arachnoiditis and disseminated intracranial lipid droplets. Neuroradiology 1995;37:146–7. 10. Yasargil MG, Abernathey CD, Sarioglu AC. Microneurosurgical treatment of intracranial dermoid and epidermoid tumours. Neurosurgery 1989;24:561–7.