Clinical Note
Meningeal Mesenchymal Chondrosarcoma of the Spine: A Case Report1 Rife E. Huckabee, MD
Primary soft-tissue chondroSarcomas are most often of the mesenchymal variety. When affecting the central nervous system, these tumors usually arise from the intracranial meninges. Intraspinal meningeal lesions are much less common but may be considered, especially in the pediatric age group, when clinical or radiologic presentation is atypical. The author presents a case report including MR imaging studies of a 7-year-old girl with intraspinal dural chondrosarcoma. Index terms: Sarcoma, 36.366 Spinal canal, MR studies, 36.1214 Spinal canal, neoplasms, 36.366
JMRI 1991; 1:93-95
1 From the Department of Radiology, University of Mississippi Medical Center, 2500 N State St. Jackson, M S 39216-4505. Received September 20, 1990;revision requested October 25: revision received and accepted October 3 1. Addrees reprint requests to the author.
OSMRI. 1991
CHONDROSARCOMA,a malignant tumor of hyaline cartilage, develops most frequently as a primary intraosseous tumor in older adults. This neoplasm has been variously classified by histologic appearance, location within the bone, and association with preexisting lesions (1).While uncommon at any age, chondrosarcomas that develop in childhood or adolescence are remarkably rare. The conventional cell type predominates at all ages: however, the mesenchymal type, an uncommon variant, may account for up to 25% of chondrosarcomas arising before adulthood (2). Moreover, approximately 80%of tumors of the rnesenchymal type are seen before the 5th decade (3). Extraskeletal soft-tissue lesions account for less than 5% of all chondrosarcomas in both children (2.5%)and adults (4.5%)and are almost always of the mesenchymal type (2). In a review of 1 1 1 cases of mesenchymal chondrosarcoma, Nakashima demonstrated the propensity of these tumors for extraosseous involvement: 34 % were primary soft-tissue lesions (3). While the pattern of distribution of skeletal chondrosarcomas clearly differs between adults and children. no such trend has been demonstrated for the extraskeletal mesenchymal tumors. Most cases have been reported as occurring in the soft tissues of the lower extremities: however, about one-fourth of the tumors have arisen from the meninges, with a tendency toward intracranial sites (3).In a recent review, Lee et al described the radiographic findings in three such cases and included the appearance of the tumors on magnetic resonance (MR)images (4).There has been little additional radiologic depiction of these tumors. In particular. there has been, to my knowledge, no recent description of the intraspinal mesenchymal chondrosarcoma. which accounts for one-third of the meningeal tumors. This case report provides a
description of the appearance of intraspinal meningeal chondrosarcoma on MR images. CASEREPORT The patient, a 7-year-old black girl, presented to her physician with the complaint of nocturnal back pain radiating into the right lower extremity. The symptoms had worsened over the previous year, and the patient had been toe-walking and tiring easily for 8 months. Other than neonatal bowel obstruction, her medical history was unremarkable. On physical examination, right quadriceps strength was minimally decreased and the right patellar reflex demonstrated clonus. No neurocutaneous stigmata were present. Results of routine laboratory tests were normal. Plain radiographs of the lumbar spine revealed mild asymmetry of the upper lumbar pedicles, possibly representing extrinsic pressure erosion. MR images were then obtained to evaluate the intraspinal contents. Spin-echo pulse sequences were performed. and the double-echo images revealed the presence of a 3 X 2cm ovoid, intradural, extramedullary mass at the L-3 level. Predominantly medium-intensity signal characteristics were demonstrated on protondensity images, with heterogeneous increased signal intensity on T2weighted images (Figs 1, 2). T1weighted images showed the mediumsignal-intensity mass filling the intrathecal space (Fig 3).No significant cystic or fatty component was demonstrated. The conus medullaris was in normal position, and no midline dorsal soft-tissue defect or mass was evident. The initial radiographic differential diagnosis included neurofibroma, epidermoid, and “dropped” metastasis. The tumor was excised at lumbar laminectomy. A smooth, intradural. extramedullary mass of firm consistency was noted attached to the inner 0
c
93
Figure 1. Double-echo sagittal images reveal a n intradural mass (arrow) displaying increased signa intensity on the T2-weigh1 ed image (TR msec/TE msec [2,000/30])(a)and medium intensity on the proton-density image (2,000/80) (b)within the subarachnoid space at the L-3 level.
b.
a.
surface of the thecal sac of the midlumbar canal and surrounded by roots of the cauda equina. At gross sectioning, the tumor appeared solid and rubbery. Light microscopy showed a sharply circumscribed. encapsulated mass consisting of small foci of cartilage within a cellular. primitive-appearing mesenchymal matrix. The chondral elements showed mild cellular atypia (Fig 4). Immunoperoxidase stained sections were positive for vimentin in areas of mesenchyme and for S l O O protein in the chondral component, consistent with mesench ymal chondrosarcoma. DISCUSSION Chondrosarcomas that affect central nervous system structures most often do so secondarily, having arisen from the skull base; these are of the conventional subtype ( 1 ) . However, from one-third to one-half of mesenchymal chondrosarcomas, a n uncommon histologic type, may develop in extraskeletal locations, including the meninges. These chondrosarcomas are readily distinguished by light microscopy, which reveals sheets of poorly differentiated cartilaginous cells within undifferentiated mesenchymal tissue. While virtually all these extraskeletal tumors have dural 0
94
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attachment, the source of the neoplastic cells is not the dura itself, since this structure normally contains no cartilage. However, it has been conjectured that primitive cartilaginous rests within the dura may subsequently undergo sarcomatous change; or, conceivably, pleuripotential mesenchyme within the dura could differentiate into cartilage and proliferate a s a malignancy (5). Radiologically, the description of meningeal mesenchymal chondrosarcoma has been limited. Indeed, the MR imaging appearance has only recently been shown by Lee et al for two of their three case reports, all of which involved intracranial lesions in adults (4). The tumor was of low signal intensity on TI-weighted images and high intensity on proton-density and T2-weighted images. The peripheral portion of one showed hyperintensity on T1-and T2-weighted images. The major differential diagnostic consideration for these lesions was atypical meningioma. However, to my knowledge, the MR imaging appearance of intraspinal dural chondrosarcoma has not been previously demonstrated. The images in this case report show a significantly different signal intensity pattern than for the intracranial lesions. A
January/February 1991
medium-intensity mass persists on the T1-weighted and proton-density images, with heterogeneous increased signal intensity on T2-weighted images. Moreover, for intradural, extramedullary tumors of the pediatric spine, the primary diagnostic considerations are quite different from those for adults. When clinical and radiologic analysis does not suggest one of the more common intraspinal tumors, one may expand the list of possibilities to include such rarities as dural chondrosarcoma. particularly in young individuals. 0 References 1. McLeod RA. Chondrosarcoma. In: Taveras J M , Ferrucci J T . eds. Radiology: diagnosis. imaging. intervention. Philadelphia: Lippincott. 1990: chap 83. 1-12. 2. Huvos AG. Marcove RC. Chondrosarcoma in the young. Am J Surg Pathol 1987: 11:930-942. 3. Nakashima Y . Mesenchymal chondrosarcoma of bone and soft tissue. Cancer 1986: 57:2444-2453. 4. Lee Y - Y . Van Tassel P. Raymond AK. Intracranial dural chondrosarcoma. A J N R 1988:9:1189-1193. 5. Scheithauer BW. Rubinstein L J . Meningeal mesenchymal chondrosarcoma. Cancer 1978: 42:2744-2752.
Figure 2. Heterogeneous signal intensity of the centrally located tumor (arrow] is demonstrated on the corla], onal images (2,000/30 2.000/80(b]). a.
b.
Figure 3. T1-weighted axial image (917/25) shows the medium-signal-intensity lesion “filling” the thecal sac and displacing the cauda equina.
Figure 4. Photomicrograph of the resected specimen shows islands of cartilage (C)amid a uniform mesenchyma1 background. (Hematoxylin-eosin stain: original magnification, X4.)
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Meningeal Mesenchymal Chondrosarcoma of the Spine: A Case Report1 Rife E. Huckabee, MD
Primary soft-tissue chondroSarcomas are most often of the mesenchymal variety. When affecting the central nervous system, these tumors usually arise from the intracranial meninges. Intraspinal meningeal lesions are much less common but may be considered, especially in the pediatric age group, when clinical or radiologic presentation is atypical. The author presents a case report including MR imaging studies of a 7-year-old girl with intraspinal dural chondrosarcoma. Index terms: Sarcoma, 36.366 Spinal canal, MR studies, 36.1214 Spinal canal, neoplasms, 36.366
JMRI 1991; 1:93-95
1 From the Department of Radiology, University of Mississippi Medical Center, 2500 N State St. Jackson, M S 39216-4505. Received September 20, 1990;revision requested October 25: revision received and accepted October 3 1. Addrees reprint requests to the author.
OSMRI. 1991
CHONDROSARCOMA,a malignant tumor of hyaline cartilage, develops most frequently as a primary intraosseous tumor in older adults. This neoplasm has been variously classified by histologic appearance, location within the bone, and association with preexisting lesions (1).While uncommon at any age, chondrosarcomas that develop in childhood or adolescence are remarkably rare. The conventional cell type predominates at all ages: however, the mesenchymal type, an uncommon variant, may account for up to 25% of chondrosarcomas arising before adulthood (2). Moreover, approximately 80%of tumors of the rnesenchymal type are seen before the 5th decade (3). Extraskeletal soft-tissue lesions account for less than 5% of all chondrosarcomas in both children (2.5%)and adults (4.5%)and are almost always of the mesenchymal type (2). In a review of 1 1 1 cases of mesenchymal chondrosarcoma, Nakashima demonstrated the propensity of these tumors for extraosseous involvement: 34 % were primary soft-tissue lesions (3). While the pattern of distribution of skeletal chondrosarcomas clearly differs between adults and children. no such trend has been demonstrated for the extraskeletal mesenchymal tumors. Most cases have been reported as occurring in the soft tissues of the lower extremities: however, about one-fourth of the tumors have arisen from the meninges, with a tendency toward intracranial sites (3).In a recent review, Lee et al described the radiographic findings in three such cases and included the appearance of the tumors on magnetic resonance (MR)images (4).There has been little additional radiologic depiction of these tumors. In particular. there has been, to my knowledge, no recent description of the intraspinal mesenchymal chondrosarcoma. which accounts for one-third of the meningeal tumors. This case report provides a
description of the appearance of intraspinal meningeal chondrosarcoma on MR images. CASEREPORT The patient, a 7-year-old black girl, presented to her physician with the complaint of nocturnal back pain radiating into the right lower extremity. The symptoms had worsened over the previous year, and the patient had been toe-walking and tiring easily for 8 months. Other than neonatal bowel obstruction, her medical history was unremarkable. On physical examination, right quadriceps strength was minimally decreased and the right patellar reflex demonstrated clonus. No neurocutaneous stigmata were present. Results of routine laboratory tests were normal. Plain radiographs of the lumbar spine revealed mild asymmetry of the upper lumbar pedicles, possibly representing extrinsic pressure erosion. MR images were then obtained to evaluate the intraspinal contents. Spin-echo pulse sequences were performed. and the double-echo images revealed the presence of a 3 X 2cm ovoid, intradural, extramedullary mass at the L-3 level. Predominantly medium-intensity signal characteristics were demonstrated on protondensity images, with heterogeneous increased signal intensity on T2weighted images (Figs 1, 2). T1weighted images showed the mediumsignal-intensity mass filling the intrathecal space (Fig 3).No significant cystic or fatty component was demonstrated. The conus medullaris was in normal position, and no midline dorsal soft-tissue defect or mass was evident. The initial radiographic differential diagnosis included neurofibroma, epidermoid, and “dropped” metastasis. The tumor was excised at lumbar laminectomy. A smooth, intradural. extramedullary mass of firm consistency was noted attached to the inner 0
c
93
Figure 1. Double-echo sagittal images reveal a n intradural mass (arrow) displaying increased signa intensity on the T2-weigh1 ed image (TR msec/TE msec [2,000/30])(a)and medium intensity on the proton-density image (2,000/80) (b)within the subarachnoid space at the L-3 level.
b.
a.
surface of the thecal sac of the midlumbar canal and surrounded by roots of the cauda equina. At gross sectioning, the tumor appeared solid and rubbery. Light microscopy showed a sharply circumscribed. encapsulated mass consisting of small foci of cartilage within a cellular. primitive-appearing mesenchymal matrix. The chondral elements showed mild cellular atypia (Fig 4). Immunoperoxidase stained sections were positive for vimentin in areas of mesenchyme and for S l O O protein in the chondral component, consistent with mesench ymal chondrosarcoma. DISCUSSION Chondrosarcomas that affect central nervous system structures most often do so secondarily, having arisen from the skull base; these are of the conventional subtype ( 1 ) . However, from one-third to one-half of mesenchymal chondrosarcomas, a n uncommon histologic type, may develop in extraskeletal locations, including the meninges. These chondrosarcomas are readily distinguished by light microscopy, which reveals sheets of poorly differentiated cartilaginous cells within undifferentiated mesenchymal tissue. While virtually all these extraskeletal tumors have dural 0
94
JMRl
attachment, the source of the neoplastic cells is not the dura itself, since this structure normally contains no cartilage. However, it has been conjectured that primitive cartilaginous rests within the dura may subsequently undergo sarcomatous change; or, conceivably, pleuripotential mesenchyme within the dura could differentiate into cartilage and proliferate a s a malignancy (5). Radiologically, the description of meningeal mesenchymal chondrosarcoma has been limited. Indeed, the MR imaging appearance has only recently been shown by Lee et al for two of their three case reports, all of which involved intracranial lesions in adults (4). The tumor was of low signal intensity on TI-weighted images and high intensity on proton-density and T2-weighted images. The peripheral portion of one showed hyperintensity on T1-and T2-weighted images. The major differential diagnostic consideration for these lesions was atypical meningioma. However, to my knowledge, the MR imaging appearance of intraspinal dural chondrosarcoma has not been previously demonstrated. The images in this case report show a significantly different signal intensity pattern than for the intracranial lesions. A
January/February 1991
medium-intensity mass persists on the T1-weighted and proton-density images, with heterogeneous increased signal intensity on T2-weighted images. Moreover, for intradural, extramedullary tumors of the pediatric spine, the primary diagnostic considerations are quite different from those for adults. When clinical and radiologic analysis does not suggest one of the more common intraspinal tumors, one may expand the list of possibilities to include such rarities as dural chondrosarcoma. particularly in young individuals. 0 References 1. McLeod RA. Chondrosarcoma. In: Taveras J M , Ferrucci J T . eds. Radiology: diagnosis. imaging. intervention. Philadelphia: Lippincott. 1990: chap 83. 1-12. 2. Huvos AG. Marcove RC. Chondrosarcoma in the young. Am J Surg Pathol 1987: 11:930-942. 3. Nakashima Y . Mesenchymal chondrosarcoma of bone and soft tissue. Cancer 1986: 57:2444-2453. 4. Lee Y - Y . Van Tassel P. Raymond AK. Intracranial dural chondrosarcoma. A J N R 1988:9:1189-1193. 5. Scheithauer BW. Rubinstein L J . Meningeal mesenchymal chondrosarcoma. Cancer 1978: 42:2744-2752.
Figure 2. Heterogeneous signal intensity of the centrally located tumor (arrow] is demonstrated on the corla], onal images (2,000/30 2.000/80(b]). a.
b.
Figure 3. T1-weighted axial image (917/25) shows the medium-signal-intensity lesion “filling” the thecal sac and displacing the cauda equina.
Figure 4. Photomicrograph of the resected specimen shows islands of cartilage (C)amid a uniform mesenchyma1 background. (Hematoxylin-eosin stain: original magnification, X4.)
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