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Pictorial review: Giant cell tumours of bone
Clinical Radiology (1998) 53, 481-489
Pictorial Review: Giant Cell Tumours of Bone M. J. LEE* 82 D. F. SALLOMI* 82 P. L. MUNK* 82 D. L. JANZEN* 82 D. G. CONNELL* 82 J. X. O ' C O N N E L L t 8 2 P. M. LOGAN,** and B. A. MASRIw182
Departments of *Radiology, tPathology and w Vancouver Hospital, SDepartment of Radiology, Vicoria General Hospital, Halifax, Nova Scotia, 82 of British Columbia, Vancouver, **Dalhousie University, Halifax, Nova Scotia, and t t Vancouver Musculoskeletal Tumour Group, Vancouver, Canada Giant cell tumour of bone is a relatively c o m m o n neoplasm with limited potential for metastatic spread. These tumours usually occur at the ends of bones with their epicentre in the epiphysis. This essay will review the various c o m m o n and some of the less frequently encountered manifestations of giant cell tumours at multiple different sites, as well as postoperative recurrence. Different imaging modalities including plain film, tomography, computed tomography and magnetic resonance imaging are shown. Lee, M. J., Sallomi, D. F., Munk, P. L., Janzen, D. L., Connell, D. G., O'Connell, J. X., Logan, P. M. & Masri, B. A. (1998). Clinical Radiology 53, 481-489. Giant Cell Tumours of Bone
Accepted for Publication 8 January 1998
Giant cell tumour (GCT) of bone is a relatively common and distinct clinicopathological entity. GCTs account for ~ 5% of primary bone tumours and 21% of benign skeletal tumours [1]. These neoplasms predominantly affect adults in the third and fourth decades of life (70%-80% of patients), although lesions that arise in the hands and feet affect a slightly younger age group. GCTs very rarely occur prior to physeal fusion [1]. Although classified as benign neoplasms, GCTs are locally aggressive with a recurrence rate of 30% to 50%. Recently, thermal and chemical treatment of the tumour bed have reduced the rate of recurrence. Rare metastases occur to the lungs (3%) and less frequently, metastases to lymph nodes, to the scalp, to the pelvis, and to the extremities may be encountered [2]. GCTs predominantly arise in long tubular bones (75% to 95%) with the majority occurring around the knee; the next most common site being the distal radius. Multifocal GCTs are rare. For unknown reasons, the incidence of GCTs is higher in China and South India. Considerable debate has existed in the pathology literature regarding the nature of GCTs and their relationship to other bone tumours [3]. In the older literature, GCTs had been termed 'osteoclastomas' on the assumption that they arose from osteoclasts. This is no longer generally accepted and the exact cell of origin is debatable. The tumour cells appear as undifferentiated, mononuclear precursors of the osteoclast which fuse to produce the characteristic giant cells. The typical histological appearance is a uniform distribution of osteoclast-like, multinucleated giant cells amongst a background of round to spindle-shaped mononuclear stromal cells (Fig. 1). These features are pathognomonic for GCT only when correlated with clinical and radiological features as multinucleated giant cells arise in several conditions including chondroblastoma, fibrous dysplasia, eosinophilic granuloma and chondromyxoid fibroma [1]. The diagnosis of GCT may be readily made if the patient's age, tumour site and radiographic appearances are typical of GCT. Two aggressive entities which can Correspondence to: Dr M.J. Lee, Department of Radiology, Vancouver Hospital and Health Sciences Centre, VGH Site, 855W. 12th Avenue, Vancouver, BC, V5Z 1M9, Canada. 9 1998 The Royal College of Radiologists.
occasionally mimic GCT both clinically and radiographically are telangiectatic or fibrogenic variants of osteosarcoma and malignant fibrous histiocytoma (MFH). Other lytic lesions which may occur in metaphyseal-epiphyseal
(a)
(b) Fig. 1 - GCT of bone. (a) Low-powerand (b) high-powermagnification photomicrographs. On the low-power setting note the evenly distributed osteoclast - giant cells (arrows). The similarity between the mononuclear nuclei (curved arrow) and the osteoclast-like giant cell nuclei (straight arrow) can be appreciated on the high powerview. Hematoxylinand eosin stain.
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locations include chondroblastoma, chondromyxoid fibroma, brown tumour of hyperparathyroidism and aneurysmal bone cyst (ABC). In the hands and feet, ABC or giant cell reparative granuloma may mimic GCT. ABC and chordoma should be considered in the differential diagnosis of a solitary lytic sacral lesion [3,4]. GCT can produce wide ranging appearances depending on site, complications such as haemorrhage or pathological fracture and after surgical intervention. This pictorial review demonstrates a spectrum of these features.
RADIOGRAPHIC FEATURES In the mature skeleton, these lesions almost invariably involve the epiphysis and metaphysis and abut an articular surface. The epicentre of the turnout is almost always eccentric to the long axis of the bone [3]. GCTs are invariably radiolucent with no internal mineralization. The borders are usually nonsclerotic and geographical (Figs 2, 3 & 4). The bone may be expanded with only a thin shell of cortex remaining and, as might be expected, with larger lesions pathological fractures (Fig. 5) can occur. Fine trabeculations at the periphery of the adjacent bone may mimic septations. Based on radiographic appearances the differentiation between an aggressive potentially metastasising GCT vs. the more common benign indolent tumour is not possible. The presence of periosteal reaction or a Codman's triangle, usually signifies a pathological fracture. Otherwise, the presence of a Codman triangle, spiculated hair-on-end or other aggressive periosteal reaction should suggest the a more ominous histology such as sarcoma. Soft tissue extension can be extremely difficult to detect or differentiate from haemorrhage secondary to a pathological fracture. CT Computed tomography will rarely add additional information that changes the differential diagnosis [1]. CT
(a)
(b) Fig. 2 - Classic GCT of the proximal tibia. A 25-year-old patient with slowly progressive knee pain over several months. (a) Anteroposterior (AP) radiograph demonstrates large eccentric radiolucent tumour extending to the articular surface medially with soft tissue extension. Note the 'septations'. (b) Coronal gross specimen through the tibia of a patient with a large GCT.
Fig. 3 - A 36-year-old male with wrist swelling. Large GCT occupying the distal diametaphysis of the distal radius, extending into the radiocarpal joint surface in the vicinity of the radial styloid. The tumour is slightly expansile and has a septated appearance. Like the tumour in Fig. 2, the borders are nonsclerotic. A periosteal reaction is seen. Note is made of medial soft tissue extension of the tumour. 9 1998 The Royal College of Radiologists, ClinicalRadiology, 53, 481 489.
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(a) (a)
(b) Fig. 4 - Sacral GCT of a 45-year-old female with poorly defined pelvic pare for at least 1 year. (a) AP film taken from an intravenous pyelogram. The inferior aspect of the sacrum demonstrates a vague, poorly appreciated radiolucency with its epicentre slightly to the left of the midline (arrows). Incidental note is made of contrast within the ureter and bladder and within the thecal sac. Overlying bowel gas precludes optimal visualization of the sacrum. (b) AP tomogram of the distal sacrum demonstrates the area of bony destruction with greater clarity. Note the lack of matrix calcification which is an important feature in sacral GCTs. The differential in this setting would include chordoma which frequently calcifies.
9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
(b) Fig. 5 - GCT with aneurysmal bone cyst (ABC) component and pathological fracture of the distal femur. A 38-year-old female with sudden onset of knee pain, swelling, and inability to bear weight. Two axial images through the distal femur demonstrate a large radiolucent lesion extending to the articular surface of the knee joint. Marked thinning of the cortex is apparent. A comminuted fracture is present with a prominent sagittal component extending into the patellofemoral compartment. Evidence of impaction and shortening of the femur is easily appreciated in part (b). Incidental note is made of a large joint effusion. ABCs are commonly associated with GCTs, although the precise aetiologic relationship remains unclear. The bone cyst component may, at times, form the bulk of the lesion. In this particular case no fluid levels are seen within the aneurysmal bone cyst which is an unusual appearance.
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(a)
(b) (c) Fig. 6 - GCT of the base of the 4th metacarpal. Six-month history of progressive hand pain and decreased grip strength. (a) AP radiograph at the time of presentation demonstrates an expansile, lytic lesion destroying the proximal third of the metacarpal and extending to the intermetacarpal and carpometacarpal joint surfaces proximally. (b) AP tomogram obtained 3 months later demonstrates distal progression of tumour growth. Note the absence of a shell of bone at the lateral aspect of the tumour distally which can occasionally be seen with markedly expansile tumours. A thin shell of remaining cortex is noted to remain at the joint surfaces proximally. (c) Axial pre and (d) post-contrast CT images. The pre-contrast images demonstrate the extensive destruction of the cortex with an incomplete shell of thin, expanded bone remaining. Defects in the shell are best appreciated in the volar aspect (arrow). Following infusion of contrast, dramatic enhancement of the tumour is appreciated.
(d) @ 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
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Fig. 7 - GCT of the radius with fluid level. A 30-year-old man with poorly localized wrist pain gradually progressing over two years. Axial CT shows an eccentrically located cystic lesion. A distinct fluid level is present
(arrow). (a)
provides a more detailed evaluation of tumour extent, which can prove helpful in surgical planning, especially in regions with complex anatomy (Fig. 6). In particular, soft tissue involvement and m'ticular surface involvement is better assessed with CT than with radiographs. CT may demonstrate fluid levels within GCTs (Fig. 7), due to intratumoral haemorrhage. Fluid levels within bone tumours are non-specific and can be seen in ABCs, chondroblastoma and telangiectactic osteosarcoma (although these tumours typically have other imaging features that allow the correct diagnosis to be inferred). The expanded and thinned cortex are vividly demonstrated and the presence or absence of matrix calcification can be assessed. The relationship of the tumour to adjacent neurovascular structures and the state of the articular surface can also be assessed.
MRI MRI provides similar information to that of CT in the evaluation of GCTs. Intratumoral fluid levels, the extent of articular surface involvement, and soft-tissue tumour extent is better evaluated on MRI than CT (Fig. 8) due to the superior soft-tissue contrast and multiplanar imaging capabilities with MRI [1,3]. These lesions are of low signal intensity to isointense to adjacent muscle on Tl-weighted sequences and are of heterogeneous high signal intensity on T2-weighted sequences [5]. The hypervascular stroma contains sinusoidal vessels which predisposes to haemorrhage
Fig. 8 - GCT of the proximal tibia. A 22-year-old female with poorly defined knee pain of several months duration and an accompanying effusion. (a) AP plain radiograph demonstrates a radiolucent lesion in the proximal anteromedial tibia extending snbarticularly. The margins of the lesion are noted to be scalloped and are largely nonsclerotic. In the AP projection, a poorly defined component is noted to be present inferior to the tibial spines. (b) Tl-weighted coronal image (TR 600 ms, TE 16 ms) shows a lobalated lesion of low to moderate signal intensity extending subarticularly. Component inferior to final spines is better appreciated. (c) Axial gradient echo 3-D Fourier transform (TR 50 ms, TE 16 ms, Flip 30 ~ image shows the structure of the tumour in great detail. Note the multiple lobulations of the tumour and the unusual extensive intratumoural septations in this case. A striking feature often seen in GCTs is the presence of fluid levels. Here, multiple fluid levels are present due to the existence of loculations (arrows). A moderate joint effusion is noted. 9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
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Fig. 9 - Solid GCT with ABC component. Well localized medial pain proximal to the joint line of the knee of several weeks duration in a 32-year-old female patient. (a) AP radiograph of the distal femur shows a markedly expansile eccentric lesion with its epicentre within the medial femoral condyle. A thin peripheral shell of bone remains. (b) Tl-weighted coronal (TR 600 ms, TE 10 ms) image shows a well defined lesion of low signal intensity with minimal inhomogeneity. Note that the thin shell of bone at the cranial aspect of the tumour, seen on the radiograph, is difficult to discern on all MR images and may in fact have been breached. (c) Axial T2-weighted fast spin echo image (TR 4000 ms, TEef 96 ms) demonstrates a well delineated tumour with multiple punctate areas of increased signal intensity. Note that a significant portion of the tumour remains of low signal intensity. (d) Sagittal STIR (TR 2000 ms, TI 150 ms, TE 30 ms) image vividly demonstrates the multiple areas of low signal intensity exhibited on the other sequences. GCTs will, on occasion, have many foci of haemosiderin deposition within them, as in this case. These foci will be of low signal intensity and likely represent the residue of previous haemorrhage.
9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
GIANT CELL TUMOURS OF BONE
(a)
487
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Fig. 10 - First metatarsal GCT. A 40-year-old patient with foot pain. (a) Pre-treatment. A large expansile lyric lesion occupies the bulk of the bone and abuts the tarsal-metatarsal joint. At the time of diagnosis 40 years ago, radiotherapy was, at times, used for treatment of these tumours. (b) Post radiation therapy. Five years later, intense sclerosis of the whole of the turnout is evident. Interestingly, this GCT does not extend to the subarticular bone which is unusual.
[6]. The phagocytosed erythrocytes lead to iron deposition in the form of haemosiderin [5]. GCTs often have extensive haemosiderin deposition within tumour tissue, resulting in a very low signal intensity on all pulse sequences (Fig. 9) [5]. This can be seen in up to 60% of cases [5]. Low signal areas may also be due to collagen deposition secondary to trauma or surgery [5]. Peritumoral marrow oedema or surrounding soft tissue oedema is rarely present in the absence of pathological fracture. Gadolinium enhancement reveals areas of hypervascularity and enhancement with a very heterogeneous signal pattern [7]. The complex appearance of GCTs may lead to the overestimation of the extent of tumour on MR scanning.
E V A L U A T I O N OF P O S T O P E R A T I V E G I A N T CELL TUMOURS Recurrence following excision of GCTs is very common. As these tumours frequently occur in younger patients, extensive resection is avoided whenever possible. Wide excision will produce lower recurrence rates, however, functional and cosmetic results are often significantly compromised. Therefore, a limited procedure such as curettage is often performed, accepting the increased risk of local recurrence [3]. With curettage, chemical or thermal ablation of the tumour bed is usually performed, which decreases the 9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
risk of recurrence. Operative intervention includes filling of the defect with bone graft or methacrylate cement. Bone cement has the advantage of providing immediate strength thereby decreasing the risk of pathological fracture. The heat produced during the polymerization process may aid in sterilization of the tumour bed. Radiation therapy is no longer used for primary treatment of GCTs (Fig. 10). GCTs are predisposed to transformation into malignant sarcomas after a short latency period of only a few years following radiotherapy [8,9]. Careful monitoring of patients following surgery is mandatory as recurrence rates in the 25% to 50% range are not unusual (Figs 11 & 12). Although recurrence usually occurs in the parent bone, soft tissue implantation can occur at the time of surgery and may be the only site of disease. Local recurrences manifest themselves within 3 years in 80% to 90% of cases [10]. Rarely, distant metastases occur in patients with recurrence. Metastases usually produce pulmonary lesions, although lymph node metastases occasionally occur [2]. Surgical resection is usually considered even if multiple lesions are present, as chemotherapy is of questionable benefit [3]. MR is the optimum technique for evaluation of recurrent or residual disease. Local experience in the follow-up of these lesions reveals three main factors in the prediction of recurrent or residual disease. Local postoperative high
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(a)
(a)
(b)
(b) Fig. 11 - Recurrent distal radial GCT. A 34-year-old patient with previous curettage and subsequent filling with radiopaque methylmethacrylate 2 years before. (a) AP radiograph. Note the large scalloped area adjacent to the bone-methacrylate interface proximally (arrows). This represents a focus of recurrent tumour. (b) Axial CT at the level of tumour recurrence shows an expanded, thinned cortex with underlying subjacent tumour.
Fig. 12 - Recurrent GCT of the proximal humems in a 37-year-old female patient. (a) Pre-surgical axial CT shows a large, inhomogeneous radiolucent lesion filling most of the humeral head. A cortical defect is located anteriorly. (b) Coronal proton density (TR 2000 ms, TE 30 ms) image obtained the same day demonstrates the high signal tumour extending to the articular surface proximally, and into the proximal diaphysis distally. (c) Postoperative CT scan 18rnonths later. Dense methyl methacrylate is present centrally within the humeral head. Numerous scalloped radiolucent areas (arrows) are present at the bone-cement interface. This scalloped appearance can represent either recurrent tumour or histiocytic granuloma formation. The time course of appearance of these radiolucent foci suggests the former, which was confiiTned at surgery. (d) T2-weighted fast-SE (TR 3247 ms, TE 96 ms) axial image shows the recurrent tumour as regions of high signal intensity (arrows) abutting the low signal methacrylate. 9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
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(c)
(d) Fig. 12 - Continued
signal within the surgical bed that exhibits a rounded masslike appearance with eccentric growth is highly suggestive of tumour. Differentiation of tumour from a giant cell reaction related to the cement can be difficult although the chronicity of the lesion and the growth pattern may help to differentiate the two entities. Giant cell granulomas most commonly develop after several years while the majority of tumour recurrences occur within 12 months after the initial surgery. In addition, tumour recurrence tends to enlarge more rapidly than giant cell granuloma. There is, however, overlap of these features between the two entities and CTguided core biopsy may be needed.
SUMMARY Plain radiographs remain the mainstay of diagnosis and evaluation of GCTs. CT and MRI play a vital role in surgical planning. Imaging follow-up in the postoperative setting is critical in view of the high recurrence rates of these tumours.
9 1998 The Royal College of Radiologists, ClinicalRadiology, 53, 481-489.
REFERENCES
1 Moser RP, KransdoffMJ, Gilkey FW, Manaster BJ. Giant cell tumor of the upper extremity. BadioGraphics 1990;10:83-102. 2 Tubbs WS, Brown LR, Beabout JW, Rock MG, Unni KK. Benign giant cell tumor of bone with pulmonary metastases. American Journal of Roentgenology 1992;158:331-334. 3 Manaster B J, Doyle AJ. Giant cell tumors of bone. Radiologic Clinics of North America 1993;31:299-323. 4 Dahlin DC. Giant cell tumor of bone: Highlights of 407 cases. American Journal of Roentgenology 1985;144:955-960. 5 Aoki J, Tanikawa H, Ishii K et aL MR findings indicative of hemosiderin in giant-cell tumor of bone: frequency, cause, and diagnostic significance. American Journal of Roentgenology 1996;166:145-148. 6 Aoki J, Moriya K, Yamashita K et aL Giant cell tumors of bone containing large amounts of hemosiderin: MR-pathologic correlation. Journal of Computer Assisted Tomography 1991;15:1024-1027. 7 Resnick D, Kyfiakos M, Greenway GD. Tumors and tumor-like lesions of bone: imaging and pathology of specific lesions. In: Resnick D, Niwayama G, eds. Diagnosis of Bone and Joint Disorders. Philadelphia: W.B. Saunders Company, 1988:3617-3888. 8 Turcotte RE, Sire FH, Unni KK. Giant cell tumor of the sacrum. Clinical Orthopedics 1993;291:215-221. 9 Sakkers RJB, Van Der Heul RO, Kroon HM, Taminiau AHM, Hogendoom PCW. Late malignant transformation of a benign giant-cell tumor of bone. Journal of Bone Joint Surgery [American] 1997;79:259-262. 10 Campanacci M, Baldini N, Boriani S, Sudanese A. Giant-cell tumor of bone. Journal of Bone Joint Surgery [American] 1987;69:106-114.
Pictorial Review: Giant Cell Tumours of Bone M. J. LEE* 82 D. F. SALLOMI* 82 P. L. MUNK* 82 D. L. JANZEN* 82 D. G. CONNELL* 82 J. X. O ' C O N N E L L t 8 2 P. M. LOGAN,** and B. A. MASRIw182
Departments of *Radiology, tPathology and w Vancouver Hospital, SDepartment of Radiology, Vicoria General Hospital, Halifax, Nova Scotia, 82 of British Columbia, Vancouver, **Dalhousie University, Halifax, Nova Scotia, and t t Vancouver Musculoskeletal Tumour Group, Vancouver, Canada Giant cell tumour of bone is a relatively c o m m o n neoplasm with limited potential for metastatic spread. These tumours usually occur at the ends of bones with their epicentre in the epiphysis. This essay will review the various c o m m o n and some of the less frequently encountered manifestations of giant cell tumours at multiple different sites, as well as postoperative recurrence. Different imaging modalities including plain film, tomography, computed tomography and magnetic resonance imaging are shown. Lee, M. J., Sallomi, D. F., Munk, P. L., Janzen, D. L., Connell, D. G., O'Connell, J. X., Logan, P. M. & Masri, B. A. (1998). Clinical Radiology 53, 481-489. Giant Cell Tumours of Bone
Accepted for Publication 8 January 1998
Giant cell tumour (GCT) of bone is a relatively common and distinct clinicopathological entity. GCTs account for ~ 5% of primary bone tumours and 21% of benign skeletal tumours [1]. These neoplasms predominantly affect adults in the third and fourth decades of life (70%-80% of patients), although lesions that arise in the hands and feet affect a slightly younger age group. GCTs very rarely occur prior to physeal fusion [1]. Although classified as benign neoplasms, GCTs are locally aggressive with a recurrence rate of 30% to 50%. Recently, thermal and chemical treatment of the tumour bed have reduced the rate of recurrence. Rare metastases occur to the lungs (3%) and less frequently, metastases to lymph nodes, to the scalp, to the pelvis, and to the extremities may be encountered [2]. GCTs predominantly arise in long tubular bones (75% to 95%) with the majority occurring around the knee; the next most common site being the distal radius. Multifocal GCTs are rare. For unknown reasons, the incidence of GCTs is higher in China and South India. Considerable debate has existed in the pathology literature regarding the nature of GCTs and their relationship to other bone tumours [3]. In the older literature, GCTs had been termed 'osteoclastomas' on the assumption that they arose from osteoclasts. This is no longer generally accepted and the exact cell of origin is debatable. The tumour cells appear as undifferentiated, mononuclear precursors of the osteoclast which fuse to produce the characteristic giant cells. The typical histological appearance is a uniform distribution of osteoclast-like, multinucleated giant cells amongst a background of round to spindle-shaped mononuclear stromal cells (Fig. 1). These features are pathognomonic for GCT only when correlated with clinical and radiological features as multinucleated giant cells arise in several conditions including chondroblastoma, fibrous dysplasia, eosinophilic granuloma and chondromyxoid fibroma [1]. The diagnosis of GCT may be readily made if the patient's age, tumour site and radiographic appearances are typical of GCT. Two aggressive entities which can Correspondence to: Dr M.J. Lee, Department of Radiology, Vancouver Hospital and Health Sciences Centre, VGH Site, 855W. 12th Avenue, Vancouver, BC, V5Z 1M9, Canada. 9 1998 The Royal College of Radiologists.
occasionally mimic GCT both clinically and radiographically are telangiectatic or fibrogenic variants of osteosarcoma and malignant fibrous histiocytoma (MFH). Other lytic lesions which may occur in metaphyseal-epiphyseal
(a)
(b) Fig. 1 - GCT of bone. (a) Low-powerand (b) high-powermagnification photomicrographs. On the low-power setting note the evenly distributed osteoclast - giant cells (arrows). The similarity between the mononuclear nuclei (curved arrow) and the osteoclast-like giant cell nuclei (straight arrow) can be appreciated on the high powerview. Hematoxylinand eosin stain.
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locations include chondroblastoma, chondromyxoid fibroma, brown tumour of hyperparathyroidism and aneurysmal bone cyst (ABC). In the hands and feet, ABC or giant cell reparative granuloma may mimic GCT. ABC and chordoma should be considered in the differential diagnosis of a solitary lytic sacral lesion [3,4]. GCT can produce wide ranging appearances depending on site, complications such as haemorrhage or pathological fracture and after surgical intervention. This pictorial review demonstrates a spectrum of these features.
RADIOGRAPHIC FEATURES In the mature skeleton, these lesions almost invariably involve the epiphysis and metaphysis and abut an articular surface. The epicentre of the turnout is almost always eccentric to the long axis of the bone [3]. GCTs are invariably radiolucent with no internal mineralization. The borders are usually nonsclerotic and geographical (Figs 2, 3 & 4). The bone may be expanded with only a thin shell of cortex remaining and, as might be expected, with larger lesions pathological fractures (Fig. 5) can occur. Fine trabeculations at the periphery of the adjacent bone may mimic septations. Based on radiographic appearances the differentiation between an aggressive potentially metastasising GCT vs. the more common benign indolent tumour is not possible. The presence of periosteal reaction or a Codman's triangle, usually signifies a pathological fracture. Otherwise, the presence of a Codman triangle, spiculated hair-on-end or other aggressive periosteal reaction should suggest the a more ominous histology such as sarcoma. Soft tissue extension can be extremely difficult to detect or differentiate from haemorrhage secondary to a pathological fracture. CT Computed tomography will rarely add additional information that changes the differential diagnosis [1]. CT
(a)
(b) Fig. 2 - Classic GCT of the proximal tibia. A 25-year-old patient with slowly progressive knee pain over several months. (a) Anteroposterior (AP) radiograph demonstrates large eccentric radiolucent tumour extending to the articular surface medially with soft tissue extension. Note the 'septations'. (b) Coronal gross specimen through the tibia of a patient with a large GCT.
Fig. 3 - A 36-year-old male with wrist swelling. Large GCT occupying the distal diametaphysis of the distal radius, extending into the radiocarpal joint surface in the vicinity of the radial styloid. The tumour is slightly expansile and has a septated appearance. Like the tumour in Fig. 2, the borders are nonsclerotic. A periosteal reaction is seen. Note is made of medial soft tissue extension of the tumour. 9 1998 The Royal College of Radiologists, ClinicalRadiology, 53, 481 489.
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(a) (a)
(b) Fig. 4 - Sacral GCT of a 45-year-old female with poorly defined pelvic pare for at least 1 year. (a) AP film taken from an intravenous pyelogram. The inferior aspect of the sacrum demonstrates a vague, poorly appreciated radiolucency with its epicentre slightly to the left of the midline (arrows). Incidental note is made of contrast within the ureter and bladder and within the thecal sac. Overlying bowel gas precludes optimal visualization of the sacrum. (b) AP tomogram of the distal sacrum demonstrates the area of bony destruction with greater clarity. Note the lack of matrix calcification which is an important feature in sacral GCTs. The differential in this setting would include chordoma which frequently calcifies.
9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
(b) Fig. 5 - GCT with aneurysmal bone cyst (ABC) component and pathological fracture of the distal femur. A 38-year-old female with sudden onset of knee pain, swelling, and inability to bear weight. Two axial images through the distal femur demonstrate a large radiolucent lesion extending to the articular surface of the knee joint. Marked thinning of the cortex is apparent. A comminuted fracture is present with a prominent sagittal component extending into the patellofemoral compartment. Evidence of impaction and shortening of the femur is easily appreciated in part (b). Incidental note is made of a large joint effusion. ABCs are commonly associated with GCTs, although the precise aetiologic relationship remains unclear. The bone cyst component may, at times, form the bulk of the lesion. In this particular case no fluid levels are seen within the aneurysmal bone cyst which is an unusual appearance.
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(a)
(b) (c) Fig. 6 - GCT of the base of the 4th metacarpal. Six-month history of progressive hand pain and decreased grip strength. (a) AP radiograph at the time of presentation demonstrates an expansile, lytic lesion destroying the proximal third of the metacarpal and extending to the intermetacarpal and carpometacarpal joint surfaces proximally. (b) AP tomogram obtained 3 months later demonstrates distal progression of tumour growth. Note the absence of a shell of bone at the lateral aspect of the tumour distally which can occasionally be seen with markedly expansile tumours. A thin shell of remaining cortex is noted to remain at the joint surfaces proximally. (c) Axial pre and (d) post-contrast CT images. The pre-contrast images demonstrate the extensive destruction of the cortex with an incomplete shell of thin, expanded bone remaining. Defects in the shell are best appreciated in the volar aspect (arrow). Following infusion of contrast, dramatic enhancement of the tumour is appreciated.
(d) @ 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
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Fig. 7 - GCT of the radius with fluid level. A 30-year-old man with poorly localized wrist pain gradually progressing over two years. Axial CT shows an eccentrically located cystic lesion. A distinct fluid level is present
(arrow). (a)
provides a more detailed evaluation of tumour extent, which can prove helpful in surgical planning, especially in regions with complex anatomy (Fig. 6). In particular, soft tissue involvement and m'ticular surface involvement is better assessed with CT than with radiographs. CT may demonstrate fluid levels within GCTs (Fig. 7), due to intratumoral haemorrhage. Fluid levels within bone tumours are non-specific and can be seen in ABCs, chondroblastoma and telangiectactic osteosarcoma (although these tumours typically have other imaging features that allow the correct diagnosis to be inferred). The expanded and thinned cortex are vividly demonstrated and the presence or absence of matrix calcification can be assessed. The relationship of the tumour to adjacent neurovascular structures and the state of the articular surface can also be assessed.
MRI MRI provides similar information to that of CT in the evaluation of GCTs. Intratumoral fluid levels, the extent of articular surface involvement, and soft-tissue tumour extent is better evaluated on MRI than CT (Fig. 8) due to the superior soft-tissue contrast and multiplanar imaging capabilities with MRI [1,3]. These lesions are of low signal intensity to isointense to adjacent muscle on Tl-weighted sequences and are of heterogeneous high signal intensity on T2-weighted sequences [5]. The hypervascular stroma contains sinusoidal vessels which predisposes to haemorrhage
Fig. 8 - GCT of the proximal tibia. A 22-year-old female with poorly defined knee pain of several months duration and an accompanying effusion. (a) AP plain radiograph demonstrates a radiolucent lesion in the proximal anteromedial tibia extending snbarticularly. The margins of the lesion are noted to be scalloped and are largely nonsclerotic. In the AP projection, a poorly defined component is noted to be present inferior to the tibial spines. (b) Tl-weighted coronal image (TR 600 ms, TE 16 ms) shows a lobalated lesion of low to moderate signal intensity extending subarticularly. Component inferior to final spines is better appreciated. (c) Axial gradient echo 3-D Fourier transform (TR 50 ms, TE 16 ms, Flip 30 ~ image shows the structure of the tumour in great detail. Note the multiple lobulations of the tumour and the unusual extensive intratumoural septations in this case. A striking feature often seen in GCTs is the presence of fluid levels. Here, multiple fluid levels are present due to the existence of loculations (arrows). A moderate joint effusion is noted. 9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
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Fig. 9 - Solid GCT with ABC component. Well localized medial pain proximal to the joint line of the knee of several weeks duration in a 32-year-old female patient. (a) AP radiograph of the distal femur shows a markedly expansile eccentric lesion with its epicentre within the medial femoral condyle. A thin peripheral shell of bone remains. (b) Tl-weighted coronal (TR 600 ms, TE 10 ms) image shows a well defined lesion of low signal intensity with minimal inhomogeneity. Note that the thin shell of bone at the cranial aspect of the tumour, seen on the radiograph, is difficult to discern on all MR images and may in fact have been breached. (c) Axial T2-weighted fast spin echo image (TR 4000 ms, TEef 96 ms) demonstrates a well delineated tumour with multiple punctate areas of increased signal intensity. Note that a significant portion of the tumour remains of low signal intensity. (d) Sagittal STIR (TR 2000 ms, TI 150 ms, TE 30 ms) image vividly demonstrates the multiple areas of low signal intensity exhibited on the other sequences. GCTs will, on occasion, have many foci of haemosiderin deposition within them, as in this case. These foci will be of low signal intensity and likely represent the residue of previous haemorrhage.
9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
GIANT CELL TUMOURS OF BONE
(a)
487
(b)
Fig. 10 - First metatarsal GCT. A 40-year-old patient with foot pain. (a) Pre-treatment. A large expansile lyric lesion occupies the bulk of the bone and abuts the tarsal-metatarsal joint. At the time of diagnosis 40 years ago, radiotherapy was, at times, used for treatment of these tumours. (b) Post radiation therapy. Five years later, intense sclerosis of the whole of the turnout is evident. Interestingly, this GCT does not extend to the subarticular bone which is unusual.
[6]. The phagocytosed erythrocytes lead to iron deposition in the form of haemosiderin [5]. GCTs often have extensive haemosiderin deposition within tumour tissue, resulting in a very low signal intensity on all pulse sequences (Fig. 9) [5]. This can be seen in up to 60% of cases [5]. Low signal areas may also be due to collagen deposition secondary to trauma or surgery [5]. Peritumoral marrow oedema or surrounding soft tissue oedema is rarely present in the absence of pathological fracture. Gadolinium enhancement reveals areas of hypervascularity and enhancement with a very heterogeneous signal pattern [7]. The complex appearance of GCTs may lead to the overestimation of the extent of tumour on MR scanning.
E V A L U A T I O N OF P O S T O P E R A T I V E G I A N T CELL TUMOURS Recurrence following excision of GCTs is very common. As these tumours frequently occur in younger patients, extensive resection is avoided whenever possible. Wide excision will produce lower recurrence rates, however, functional and cosmetic results are often significantly compromised. Therefore, a limited procedure such as curettage is often performed, accepting the increased risk of local recurrence [3]. With curettage, chemical or thermal ablation of the tumour bed is usually performed, which decreases the 9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
risk of recurrence. Operative intervention includes filling of the defect with bone graft or methacrylate cement. Bone cement has the advantage of providing immediate strength thereby decreasing the risk of pathological fracture. The heat produced during the polymerization process may aid in sterilization of the tumour bed. Radiation therapy is no longer used for primary treatment of GCTs (Fig. 10). GCTs are predisposed to transformation into malignant sarcomas after a short latency period of only a few years following radiotherapy [8,9]. Careful monitoring of patients following surgery is mandatory as recurrence rates in the 25% to 50% range are not unusual (Figs 11 & 12). Although recurrence usually occurs in the parent bone, soft tissue implantation can occur at the time of surgery and may be the only site of disease. Local recurrences manifest themselves within 3 years in 80% to 90% of cases [10]. Rarely, distant metastases occur in patients with recurrence. Metastases usually produce pulmonary lesions, although lymph node metastases occasionally occur [2]. Surgical resection is usually considered even if multiple lesions are present, as chemotherapy is of questionable benefit [3]. MR is the optimum technique for evaluation of recurrent or residual disease. Local experience in the follow-up of these lesions reveals three main factors in the prediction of recurrent or residual disease. Local postoperative high
488
CLINICAL RADIOLOGY
(a)
(a)
(b)
(b) Fig. 11 - Recurrent distal radial GCT. A 34-year-old patient with previous curettage and subsequent filling with radiopaque methylmethacrylate 2 years before. (a) AP radiograph. Note the large scalloped area adjacent to the bone-methacrylate interface proximally (arrows). This represents a focus of recurrent tumour. (b) Axial CT at the level of tumour recurrence shows an expanded, thinned cortex with underlying subjacent tumour.
Fig. 12 - Recurrent GCT of the proximal humems in a 37-year-old female patient. (a) Pre-surgical axial CT shows a large, inhomogeneous radiolucent lesion filling most of the humeral head. A cortical defect is located anteriorly. (b) Coronal proton density (TR 2000 ms, TE 30 ms) image obtained the same day demonstrates the high signal tumour extending to the articular surface proximally, and into the proximal diaphysis distally. (c) Postoperative CT scan 18rnonths later. Dense methyl methacrylate is present centrally within the humeral head. Numerous scalloped radiolucent areas (arrows) are present at the bone-cement interface. This scalloped appearance can represent either recurrent tumour or histiocytic granuloma formation. The time course of appearance of these radiolucent foci suggests the former, which was confiiTned at surgery. (d) T2-weighted fast-SE (TR 3247 ms, TE 96 ms) axial image shows the recurrent tumour as regions of high signal intensity (arrows) abutting the low signal methacrylate. 9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 481-489.
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(c)
(d) Fig. 12 - Continued
signal within the surgical bed that exhibits a rounded masslike appearance with eccentric growth is highly suggestive of tumour. Differentiation of tumour from a giant cell reaction related to the cement can be difficult although the chronicity of the lesion and the growth pattern may help to differentiate the two entities. Giant cell granulomas most commonly develop after several years while the majority of tumour recurrences occur within 12 months after the initial surgery. In addition, tumour recurrence tends to enlarge more rapidly than giant cell granuloma. There is, however, overlap of these features between the two entities and CTguided core biopsy may be needed.
SUMMARY Plain radiographs remain the mainstay of diagnosis and evaluation of GCTs. CT and MRI play a vital role in surgical planning. Imaging follow-up in the postoperative setting is critical in view of the high recurrence rates of these tumours.
9 1998 The Royal College of Radiologists, ClinicalRadiology, 53, 481-489.
REFERENCES
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