Skeletal Radiol (1992) 21 : 339-342
Skeletal Radiology
Case report 741 Hiroyuki Tsuchiya, M.D., Ph.D. 1, Katsuro Tomita, M.D., Ph.D. 1, Toshinori Tsuchida, M.D. 1, Yoshimichi Ueda, M.D., Ph.D. 2, Albert Roessner, M.D. 2, and Masayuki Suzuki, M.D., Ph.D. 3 Departments of 1 Orthopaedic Surgery and 3 Radiology, School of Medicine, Kanazawa University, Kanazawa, Japan, and 2 Gerhard Domagk Institute of Pathology, Westf/ilische Wilhetms University, Mfinster, F R G
Radiological studies
Fig. 1. A Lateral tomogram shows compression fracture of the second thoracic vertebra. B Posteroanterior (PA) myelogram combined with opaque medium administered above and below the lesion shows a complete block at the level of T2, with the contrast medium column shifted to the left. C Computed tomography (CT) scan combined with myelography shows involvement of the vertebral body and the neural arch and the pseudotrabeculations with incomplete septae. The spinal cord is shifted to the left by the tumor extending into the spinal canal. D A T2-weighted magnetic resonance (MR) image shows considerable soft-tissue extension of the tumor and compression of the spinal cord
Clinical information A 19-year-old w o m a n presented with a 2-week history of disturbance of gait and pain in the back. A neurological disorder developed rapidly after admission, and physical examination revealed paraplegia below the second thoracic segment. Plain radiographs and tomograms showed a lytic lesion affected the second thoracic vertebra with collapse. The cortex was not expanded, and no evidence of a calcified or ossified matrix was noted. Myelography revealed a complete block at T2, and an extradural mass was suspected, because the column of contrast medium was displaced to the left. Computed tomography (CT) scans, combined with myelography, showed the presence of a lesion involving both the vertebral body and the neural arch of the 2nd thoracic vertebra. Cortical expansion of the lamina with partial disruption of cortical continuity was observed. A small sclerotic area in the right side of the vertebral body and pseudotrabeculations associated with incomplete septae were noted. On T2-weighted magnetic resonance imaging (MRI), the spinal cord was observed to be compressed both anteriorly and posteriorly by the lesion. A high signal intensity around the spinal cord from the lower edge of the 6th cervical vertebra to the 2nd thoracic vertebra implied the presence of a soft-tissue mass affecting the spinal canal (Fig. 1). A technetium-99m isotope scan was grossly abnormal, with increased uptake in the entire area of the second thoracic vertebra. An operation was performed. Address reprint requests to: Hiroyuki Tsuchiya,
M.D., Ph.D., Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920, Japan 9 1992 International Skeletal Society
340
Diagnosis: Chondromyxoid fibroma of T2 In view of the aggressive features of the lesion, an initial diagnosis of osteosarcoma or giant cell tumor of the spine was made. The patient was young for a chondrosarcoma. Chondromyxoid fibroma (CMF) was considered highly unlikely because of the location of the lesion and the rapid progression of neurological deficits. The differential diagnosis also included aneurysmal bone cyst and eosinophilic granuloma, but as highly unlikely possibilities.
H. Tsuchiya et al. : Case report 741 At surgery, a firm, fleshy lesion was present, centering over T2 (Fig. 2). The tumor extended to the spinal canal with cortical destruction of T2. Furthermore, the spinal cord was markedly compressed by the mass. An en-bloc total vertebrectomy was performed on T2 following laminectomies from C7 to T3. Ceramic spacer implantation with methylmethacrylate and Luque segmental sublaminar wiring was performed from C4 to T6. The histological examination of the resected specimen demonstrated a chondroid tumor with a lobular
Pathological and follow-up radiological studies
Fig. 2. Intraoperative photograph shows the tumor mass (arrow) extending into the spinal canal Fig. 3. A Photomicrograph of the resected tumor at a low magnification demonstrates chondroid lobules surrounded by peripheral condensation of myxoid and spindly fibroid elements (H & E, x 136). B Photomicrograph at a high magnification shows details of a hypereellular fibroid element which comprises spindle cells with round to ovoid, bland nuclei. Mitoses are completely absent (H & E, x 550)
pattern of growth. Each lobule consisted of eosinophilic chondroid nodules surrounded by a peripheral condensation of fibroid cells with a spindle configuration. Round to ovoid bland nuclei were present. The nucleoli were small and indistinct, and the cell borders were unsharp. Myxoid elements were also observed in some areas, especially in the peripheral portion of chondroid nodules where the tumor ceils showed considerable cellularity. A few cells showed bizarre hyperchromatic nuclei; cellular atypia was generally mild, and mitoses were completely absent (Fig. 3).
H. Tsuchiyaet al. : Case report 741
341
The margin of the lesion was clear and well-demarcated from the host lamellar bone. Infiltration by multinucleated, osteoclast-like giant cells, areas of chondroblastic differentiation, or loci of tumor osteoid were not noted. Immunohistochemically, the tumor cells, especially those within the chondroid nodules, were positive for $100 protein, a feature compatible with the diagnosis of CMF. Discussion
The interesting features in the case presented are the unusual site of the tumor, the rapid progression of neurological symptoms and signs, and the aggressive radiological findings accompanied by cortical destruction and a large extraosseous mass. Initially, several pathologists made a provisional diagnosis of osteosarcoma upon viewing the intraoperative studies of the frozen sections. We therefore implanted an artificial vertebral body to give radiation and chemotherapy postoperatively. The pathologists, however, had in the meantime made a firm diagnosis of CMF with decalcified, paraffin-embedded sections. Professor K.K. Unni, pathologist at the Mayo Clinic in Rochester, Minnesota, was also asked for his opinion. He also believed that the histological appearance and the other features were, as previously reported [1, 13, 15], typical of chondromyxoid fibroma and that the likely cause for the aggressive features radiologically was the unusually rapid growth associated with the site of the lesion. CMF was described by Jaffe and Lichtenstein in 1948 [7], when they presented 8 cases and emphasized the risk of mistaking this benign neoplasm for a malignant tumor. The typical CMF is located in the metaphyseal region of a long bone and may abut on or be present at varying distances from the epiphyseal line. The lesion occasionally involves both the metaphysis and the epiphysis. The typical radiological feature is an eccentric, radiolucent, metaphyseal lesion which may be contiguous with the physis. The well-defined margins may be slightly sclerotic. The cortex may be thin, erroded, or even absent.
Fig. 4A, B. AP and lateral radiographs of the thoracic spine 2 years after surgery
The tumor has a lobulated appearance with pseudotrabeculations due to incomplete septae [5, 8, 9, 12]. Periosteal reaction, calcification (noted radiotogically), and pathological fracture radiographically are unusual [6]. It is reported that CMF in a young child often shows aggressive features, with expansion of the partly invisible cortex and the periosteal reaction due to rapid growth [3]. Some authors have reported epiphyseal involvement as an indication of increased aggressiveness [10, 11]. The lesion, on the other hand, rarely occurs in the spine [4], where it is liable to present with more aggressive features than CMF in a long bone. Benson and Bass reported a case of a grossly destructive CMF of the spinous processes of the 2nd and 3rd thoracic vertebrae that was observed at surgery to extend not only into the adjacent soft tissue but also into the spinal canal [1]. Standefer et al. stated that lesions affecting the vertebral body appear to extend beyond the confines of the periosteum [13]. Zillmer and Dorfman reported that out of three vertebral lesions of CMF, two not only involved soft tissues but also spread into the spinal canal [15]. In the case presented in this paper, the tumor involved both the vertebral body and
the neural arch and also extended into the spinal canal, causing rapid paraplegia. Among spinal lesions, CMF should be differentiated from malignant neoplasms, especially chondrosarcoma and osteosarcoma, because of their aggressive features. The spine is one of the sites of predilection for chondrosarcoma, and lytic changes predominate in the radiological feature of osteosarcoma of the spine [4, 14]. Histopathologically, CMF is one of the tumors that is diagnosed easily as a general rule by an experienced skeletal pathologist. Its considerably large size, its pleomorphism, and hyperchromia of the nuclei in the CMF, however, may cause the tumor to be mistaken for a chondrosarcoma or other malignant lesion (e.g., osteosarcoma), if attention is concentrated only on a section of the cellular details of the lesion. Large pleomorphic cells with hyperchromatic nuclei may be seen, but no mitoses are present. This feature differentiates the tumor from a chondrosarcoma. Giant cells, if present, are nonspecific and reactive [2, 6, 9, 12]. Block excision of the involved area, if feasible, is the best means of treatment. Curettage alone is associated with a risk of recurrence in 20%-80% of cases. Bone grafting,
342 after excision and curettage, is often necessary because it reduces the risk o f recurrence [2, 6, 10, 12]. To reduce this risk, we p e r f o r m e d an en-bloc total v e r t e b r e c t o m y with a Gigli's saw following l a m i n e c t o m y and spinal instrumentation. We used the L u q u e m e t h o d and a ceramic spacer for this one-stage posterior procedure. The patient recovered completely f r o m the paraplegia 1 week after the spinal cord decompression and spinal stabilization. Two years after operation, no evidence o f recurrence is present. Solid bone grafting for the replacem e n t o f the ceramic spacer m a y be needed in the future to obtain permanent stability (Fig. 4). In summary, we have reported a m o s t interesting case o f C M F on the 2nd thoracic vertebra. The t u m o r showed aggressive features radiologically and gave rise to a rapid progression o f neurological s y m p t o m s and signs. The aggressive nature o f C M F o f the spine was discussed, and the tendency for such lesions to simulate c h o n d r o s a r c o m a or o s t e o s a r c o m a
H. Tsuchiya et al.: Case report 741 was stressed. The rarity o f occurrence o f C M F in the spine was also considered.
References 1. Benson WR, Bass S (1955) Chondromyxoid fibroma: first report of occurrence of the tumor in vertebral column. Am J Clin Pathol 25:1290 2. Dahlin DC, Unni KK (1986) Bone tumors, 4th edn. Thomas, Springfield 3. Davey HA, Cremin BJ, Smith CS (1990) Case report 625. Skeletal Radiol 19:395 4. Delamarter RB, Sachs BL, Thompson GH, Bohlman HH, Makley JT, Carter JR (1990) Primary neoplasms of the thoracic and lumbar spine: an analysis of 29 consecutive cases. Clin Orthop 256: 87 5. Feldman F, Hecht H, Johnston A (1979) Chondromyxoid fibroma of bone. Radiology 94: 249 6. Gherlinzoni R, Rock M, Picci P (1983) Chondromyxoid fibroma. J Bone Joint Surg [Am] 65:198 7. Jaffe HL, Lichtenstein L (1948) Chondromyxoid fibroma of bone. A distinct benign tumor likely to be mistaken
especially for chondrosarcoma. Arch Pathol 45 : 541 8. Lichtenstein L (1977) Bone tumours, 5th edn. Mosby, St. Louis 9. Rahimi A, Beabout J, Ivins A, Dahlin D (1972) Chondromyxoid fibroma: a clinicopathologic study of 76 cases. 30 : 726 10. Ralph L (1962) Chondromyxoid fibroma of bone. J Bone Joint Surg [Br] 44 : 7 11. Scaglietti O, Stringa G (1961) Myxoma of bone in childhood. J Bone Joint Surg [Am] 43 : 67 12. Schajowicz F, Gallardo H (1979) Chondromyxoid fibroma of bone: a clinicopathological study of thirty-two cases. J Bone Joint Surg [Br] 53:198 13. Standefer M, Hardy RW, Marks K (1982) Chondromyxoid fibroma of the cervical spine - a case report with a review of the literature and a description of an operative approach to the lower anterior cervical spine. Neurosurgery 11:288 14. Sundaresan N, Rosen G, Huvos AG, Krol G (1988) Combined treatment of osteosarcoma of the spine. Neurosurgery 23:714 15. Zillmer DA, Dorfman H (1989) Chondromyxoid fibroma of bone: thirty-six cases with clinieopathologic correlation. Hum Pathol 20 : 952
Skeletal Radiology
Case report 741 Hiroyuki Tsuchiya, M.D., Ph.D. 1, Katsuro Tomita, M.D., Ph.D. 1, Toshinori Tsuchida, M.D. 1, Yoshimichi Ueda, M.D., Ph.D. 2, Albert Roessner, M.D. 2, and Masayuki Suzuki, M.D., Ph.D. 3 Departments of 1 Orthopaedic Surgery and 3 Radiology, School of Medicine, Kanazawa University, Kanazawa, Japan, and 2 Gerhard Domagk Institute of Pathology, Westf/ilische Wilhetms University, Mfinster, F R G
Radiological studies
Fig. 1. A Lateral tomogram shows compression fracture of the second thoracic vertebra. B Posteroanterior (PA) myelogram combined with opaque medium administered above and below the lesion shows a complete block at the level of T2, with the contrast medium column shifted to the left. C Computed tomography (CT) scan combined with myelography shows involvement of the vertebral body and the neural arch and the pseudotrabeculations with incomplete septae. The spinal cord is shifted to the left by the tumor extending into the spinal canal. D A T2-weighted magnetic resonance (MR) image shows considerable soft-tissue extension of the tumor and compression of the spinal cord
Clinical information A 19-year-old w o m a n presented with a 2-week history of disturbance of gait and pain in the back. A neurological disorder developed rapidly after admission, and physical examination revealed paraplegia below the second thoracic segment. Plain radiographs and tomograms showed a lytic lesion affected the second thoracic vertebra with collapse. The cortex was not expanded, and no evidence of a calcified or ossified matrix was noted. Myelography revealed a complete block at T2, and an extradural mass was suspected, because the column of contrast medium was displaced to the left. Computed tomography (CT) scans, combined with myelography, showed the presence of a lesion involving both the vertebral body and the neural arch of the 2nd thoracic vertebra. Cortical expansion of the lamina with partial disruption of cortical continuity was observed. A small sclerotic area in the right side of the vertebral body and pseudotrabeculations associated with incomplete septae were noted. On T2-weighted magnetic resonance imaging (MRI), the spinal cord was observed to be compressed both anteriorly and posteriorly by the lesion. A high signal intensity around the spinal cord from the lower edge of the 6th cervical vertebra to the 2nd thoracic vertebra implied the presence of a soft-tissue mass affecting the spinal canal (Fig. 1). A technetium-99m isotope scan was grossly abnormal, with increased uptake in the entire area of the second thoracic vertebra. An operation was performed. Address reprint requests to: Hiroyuki Tsuchiya,
M.D., Ph.D., Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920, Japan 9 1992 International Skeletal Society
340
Diagnosis: Chondromyxoid fibroma of T2 In view of the aggressive features of the lesion, an initial diagnosis of osteosarcoma or giant cell tumor of the spine was made. The patient was young for a chondrosarcoma. Chondromyxoid fibroma (CMF) was considered highly unlikely because of the location of the lesion and the rapid progression of neurological deficits. The differential diagnosis also included aneurysmal bone cyst and eosinophilic granuloma, but as highly unlikely possibilities.
H. Tsuchiya et al. : Case report 741 At surgery, a firm, fleshy lesion was present, centering over T2 (Fig. 2). The tumor extended to the spinal canal with cortical destruction of T2. Furthermore, the spinal cord was markedly compressed by the mass. An en-bloc total vertebrectomy was performed on T2 following laminectomies from C7 to T3. Ceramic spacer implantation with methylmethacrylate and Luque segmental sublaminar wiring was performed from C4 to T6. The histological examination of the resected specimen demonstrated a chondroid tumor with a lobular
Pathological and follow-up radiological studies
Fig. 2. Intraoperative photograph shows the tumor mass (arrow) extending into the spinal canal Fig. 3. A Photomicrograph of the resected tumor at a low magnification demonstrates chondroid lobules surrounded by peripheral condensation of myxoid and spindly fibroid elements (H & E, x 136). B Photomicrograph at a high magnification shows details of a hypereellular fibroid element which comprises spindle cells with round to ovoid, bland nuclei. Mitoses are completely absent (H & E, x 550)
pattern of growth. Each lobule consisted of eosinophilic chondroid nodules surrounded by a peripheral condensation of fibroid cells with a spindle configuration. Round to ovoid bland nuclei were present. The nucleoli were small and indistinct, and the cell borders were unsharp. Myxoid elements were also observed in some areas, especially in the peripheral portion of chondroid nodules where the tumor ceils showed considerable cellularity. A few cells showed bizarre hyperchromatic nuclei; cellular atypia was generally mild, and mitoses were completely absent (Fig. 3).
H. Tsuchiyaet al. : Case report 741
341
The margin of the lesion was clear and well-demarcated from the host lamellar bone. Infiltration by multinucleated, osteoclast-like giant cells, areas of chondroblastic differentiation, or loci of tumor osteoid were not noted. Immunohistochemically, the tumor cells, especially those within the chondroid nodules, were positive for $100 protein, a feature compatible with the diagnosis of CMF. Discussion
The interesting features in the case presented are the unusual site of the tumor, the rapid progression of neurological symptoms and signs, and the aggressive radiological findings accompanied by cortical destruction and a large extraosseous mass. Initially, several pathologists made a provisional diagnosis of osteosarcoma upon viewing the intraoperative studies of the frozen sections. We therefore implanted an artificial vertebral body to give radiation and chemotherapy postoperatively. The pathologists, however, had in the meantime made a firm diagnosis of CMF with decalcified, paraffin-embedded sections. Professor K.K. Unni, pathologist at the Mayo Clinic in Rochester, Minnesota, was also asked for his opinion. He also believed that the histological appearance and the other features were, as previously reported [1, 13, 15], typical of chondromyxoid fibroma and that the likely cause for the aggressive features radiologically was the unusually rapid growth associated with the site of the lesion. CMF was described by Jaffe and Lichtenstein in 1948 [7], when they presented 8 cases and emphasized the risk of mistaking this benign neoplasm for a malignant tumor. The typical CMF is located in the metaphyseal region of a long bone and may abut on or be present at varying distances from the epiphyseal line. The lesion occasionally involves both the metaphysis and the epiphysis. The typical radiological feature is an eccentric, radiolucent, metaphyseal lesion which may be contiguous with the physis. The well-defined margins may be slightly sclerotic. The cortex may be thin, erroded, or even absent.
Fig. 4A, B. AP and lateral radiographs of the thoracic spine 2 years after surgery
The tumor has a lobulated appearance with pseudotrabeculations due to incomplete septae [5, 8, 9, 12]. Periosteal reaction, calcification (noted radiotogically), and pathological fracture radiographically are unusual [6]. It is reported that CMF in a young child often shows aggressive features, with expansion of the partly invisible cortex and the periosteal reaction due to rapid growth [3]. Some authors have reported epiphyseal involvement as an indication of increased aggressiveness [10, 11]. The lesion, on the other hand, rarely occurs in the spine [4], where it is liable to present with more aggressive features than CMF in a long bone. Benson and Bass reported a case of a grossly destructive CMF of the spinous processes of the 2nd and 3rd thoracic vertebrae that was observed at surgery to extend not only into the adjacent soft tissue but also into the spinal canal [1]. Standefer et al. stated that lesions affecting the vertebral body appear to extend beyond the confines of the periosteum [13]. Zillmer and Dorfman reported that out of three vertebral lesions of CMF, two not only involved soft tissues but also spread into the spinal canal [15]. In the case presented in this paper, the tumor involved both the vertebral body and
the neural arch and also extended into the spinal canal, causing rapid paraplegia. Among spinal lesions, CMF should be differentiated from malignant neoplasms, especially chondrosarcoma and osteosarcoma, because of their aggressive features. The spine is one of the sites of predilection for chondrosarcoma, and lytic changes predominate in the radiological feature of osteosarcoma of the spine [4, 14]. Histopathologically, CMF is one of the tumors that is diagnosed easily as a general rule by an experienced skeletal pathologist. Its considerably large size, its pleomorphism, and hyperchromia of the nuclei in the CMF, however, may cause the tumor to be mistaken for a chondrosarcoma or other malignant lesion (e.g., osteosarcoma), if attention is concentrated only on a section of the cellular details of the lesion. Large pleomorphic cells with hyperchromatic nuclei may be seen, but no mitoses are present. This feature differentiates the tumor from a chondrosarcoma. Giant cells, if present, are nonspecific and reactive [2, 6, 9, 12]. Block excision of the involved area, if feasible, is the best means of treatment. Curettage alone is associated with a risk of recurrence in 20%-80% of cases. Bone grafting,
342 after excision and curettage, is often necessary because it reduces the risk o f recurrence [2, 6, 10, 12]. To reduce this risk, we p e r f o r m e d an en-bloc total v e r t e b r e c t o m y with a Gigli's saw following l a m i n e c t o m y and spinal instrumentation. We used the L u q u e m e t h o d and a ceramic spacer for this one-stage posterior procedure. The patient recovered completely f r o m the paraplegia 1 week after the spinal cord decompression and spinal stabilization. Two years after operation, no evidence o f recurrence is present. Solid bone grafting for the replacem e n t o f the ceramic spacer m a y be needed in the future to obtain permanent stability (Fig. 4). In summary, we have reported a m o s t interesting case o f C M F on the 2nd thoracic vertebra. The t u m o r showed aggressive features radiologically and gave rise to a rapid progression o f neurological s y m p t o m s and signs. The aggressive nature o f C M F o f the spine was discussed, and the tendency for such lesions to simulate c h o n d r o s a r c o m a or o s t e o s a r c o m a
H. Tsuchiya et al.: Case report 741 was stressed. The rarity o f occurrence o f C M F in the spine was also considered.
References 1. Benson WR, Bass S (1955) Chondromyxoid fibroma: first report of occurrence of the tumor in vertebral column. Am J Clin Pathol 25:1290 2. Dahlin DC, Unni KK (1986) Bone tumors, 4th edn. Thomas, Springfield 3. Davey HA, Cremin BJ, Smith CS (1990) Case report 625. Skeletal Radiol 19:395 4. Delamarter RB, Sachs BL, Thompson GH, Bohlman HH, Makley JT, Carter JR (1990) Primary neoplasms of the thoracic and lumbar spine: an analysis of 29 consecutive cases. Clin Orthop 256: 87 5. Feldman F, Hecht H, Johnston A (1979) Chondromyxoid fibroma of bone. Radiology 94: 249 6. Gherlinzoni R, Rock M, Picci P (1983) Chondromyxoid fibroma. J Bone Joint Surg [Am] 65:198 7. Jaffe HL, Lichtenstein L (1948) Chondromyxoid fibroma of bone. A distinct benign tumor likely to be mistaken
especially for chondrosarcoma. Arch Pathol 45 : 541 8. Lichtenstein L (1977) Bone tumours, 5th edn. Mosby, St. Louis 9. Rahimi A, Beabout J, Ivins A, Dahlin D (1972) Chondromyxoid fibroma: a clinicopathologic study of 76 cases. 30 : 726 10. Ralph L (1962) Chondromyxoid fibroma of bone. J Bone Joint Surg [Br] 44 : 7 11. Scaglietti O, Stringa G (1961) Myxoma of bone in childhood. J Bone Joint Surg [Am] 43 : 67 12. Schajowicz F, Gallardo H (1979) Chondromyxoid fibroma of bone: a clinicopathological study of thirty-two cases. J Bone Joint Surg [Br] 53:198 13. Standefer M, Hardy RW, Marks K (1982) Chondromyxoid fibroma of the cervical spine - a case report with a review of the literature and a description of an operative approach to the lower anterior cervical spine. Neurosurgery 11:288 14. Sundaresan N, Rosen G, Huvos AG, Krol G (1988) Combined treatment of osteosarcoma of the spine. Neurosurgery 23:714 15. Zillmer DA, Dorfman H (1989) Chondromyxoid fibroma of bone: thirty-six cases with clinieopathologic correlation. Hum Pathol 20 : 952
