Chondrosarcoma
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Chondrosarcoma, Secondary to Enchondroma
Definition | Demographics | Clinical Presentation | Natural History | Radiographic Features | Imaging Studies | Gross Features | Microscopic Features | Treatment | Example Cases | Self-evaluation | References Chondrosarcoma secondary to enchondroma is a primary neoplasm of cartilaginous histogenesis arising from a pre-existing benign enchondroma. DemographicsAge: 30 - 50 Sex: M > F Site: The most common precursor is multiple enchondroma or Ollier's disease. This phenomenon is rare in solitary enchondroma or synovial chondromatosis. Clinical PresentationThe patient presents with pain at the site of a previously-painless enchondroma. Natural HistorySlow, displacing growth is characteristic of this tumor with very late transition to a high-grade lesion and risk of metastasis. The survival rate is excellent with adequate treatment prior to transition. Radiographic FeaturesOn radiograph, there is an expanding, radiolucent zone surrounding a calcified enchondroma with endosteal scalloping and periosteal, cortical thickening. [X-Ray] This radiograph shows the original enchondroma at first presentation. The patient was asymptomatic at this time. [X-Ray] This radiograph was made fourteen years later when the patient presented with a secondary chondrosarcoma. [X-Ray] This radiograph shows a calcified enchondroma in the medullary canal of the femur. Proximal to the enchondroma is a radiolucent lesion that has "expanded" the cortex by a combination of endosteal resorption and periosteal apposition. These are the radiographic signs of malignant transformation. [X Ray] This is a closer view of the area of transformation. [X-Ray] This is a radiograph of a recurrent chondrosarcoma of the tarsal in Ollier's disease. This radiolucent, "expansile" lesion developed shortly after curettage of a secondary chondrosarcoma misinterpreted as a benign enchondroma. Imaging StudiesIsotope ScanThe isotope scan shows a moderate increase in uptake at the site of a previous, "hot", benign lesion. A "hot" scan does not mean the lesion is malignant! There must be a change in the intensity of the uptake; therefore, it is evident that serial scans are required. [Iso-Scan] This isotope scan of a secondary chondrosarcoma of the proximal humerus shows increased uptake considerably beyond the limits of the original enchondroma. This strongly suggests malignant transformation. [Iso-Scan] An isotope scan shows the enchondroma distally with a secondary chondrosarcoma proximally. For correlation with the radiograph, see [X-Ray] . AngiographyOn angiography, the lesion is vascular. [X-Ray] This angiogram shows the displacement of the veins about a chondrosarcoma of the proximal radius secondary to Maffucci's syndrome. CT ScanA CT scan shows a lobulated, calcified mass extending from the periphery of an ossified exostosis or irregular, radiolucent zone intruding into cortices from an enchondroma. Calcification in benign enchondroma has a "smoke ring" configuration while, in chondrosarcoma, it is "popcorn" or flocculent. [CT Scan] This magnification of a CT cut through a secondary chondrosarcoma of the humeral head shows the dense calcification of the enchondroma and the destructive edge of the lesion with cortical perforation and extension into the soft tissues. MRIA zone of low-intensity signal about an exostosis or enchondroma shows the malignant cartilage. A zone of high-intensity signal may mean a bursa or reactive inflammation rather than malignant transformation. [CT Scan] This is a T-1 weighted MRI of the femur containing an enchondroma and a secondary chondrosarcoma. The low intensity signal outlines the enchondroma while the central, higher intensity signal demonstrates the extent of the secondary chondrosarcoma. [CT Scan] This is an axial MRI cut through an interosseous, secondary chondrosarcoma. The abnormal signal about the femur represents reactive inflammation rather than extraosseous extension of the tumor through the cortex. Gross FeaturesSecondary chondrosarcomas developing from enchondroma show a zone of pearl-gray, neoplastic, immature cartilage about the central, calcified enchondroma. These are most often Stage I-B lesions. [Gross Path] The cut surface of this secondary chondrosarcoma shows the typical, pearl-gray tissue of low-grade chondrosarcoma. Remnants of the original enchondroma are seen as white, calcified areas. [Gross Path] This specimen from a patient with Ollier's disease shows the appearance of a secondary chondrosarcoma in the tibial epiphysis. There is extension through the cortex into the soft tissues and a benign enchondroma in the medullary canal of the diaphysis. [Gross Path] This specimen shows the typical, pearl-gray appearance of an enchondroma in the lower half of the specimen and the transition to secondary chondrosarcoma at the midportion where the femur is slightly "expanded". [Gross Path] On closer view of the above image, the area of transformation is at the upper end of the specimen. [Gross Path] This is a still closer view of the preceding two images. Microscopic FeaturesOn microscopic exam, active, cellular cartilage with plump nuclei in the peripheral rim or zone are noted with only occasional double nuclei surrounding the benign features of an enchondroma. These are universally low grade (G1) until very late transition and may be very difficult to distinguish histologically from active but benign enchondroma. [Micro] The deeper-stained tissue in the center represents remnants of the pre-existing enchondroma. The surrounding, less-mature, more-cellular, cartilaginous tissue represents the sarcomatous component. [Micro] This immature, cartilaginous tissue is from the periphery of the sarcomatous component. [Micro] This photomicrograph shows the cellular appearance of a secondary, myxoid chondrosarcoma from the tarsal in a patient with Ollier's disease. The immature matrix is very faintly stained, and the chondrocytes show little cellular atypia. [Micro] A photomicrograph from an area of enchondroma contrasts sharply with the more cellular pattern of secondary chondrosarcoma in [Micro] TreatmentSurgeryWide, en bloc excision is indicated. If a prior, intracapsular or marginal excision has recently been done, wide re-excision, after MRI imaging, is necessary to ascertain all the tissues contaminated by the previous procedure. All contaminated tissue must be included in the re-excision bloc. Recurrences tend to be multiple, small nodules so widely scattered that excision or resection becomes impractical, and amputation is required to achieve a wide margin. [Gross Path] An above-knee amputation was done for a recurrent chondrosarcoma of the tarsals in the foot and a chondrosarcoma of the proximal tibia, both secondary to enchondromas in Ollier's disease. Radiation TherapyRadiation is ineffective. ChemotherapyChemotherapy is ineffective. Example Cases
Case
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Case
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Case
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4375.1 Self-evaluationReferencesGarrison, R. C.; Unni, K. K.; McLeod, R. A., et. al.: "Chondrosarcoma Arising in Osteochondroma," Cancer, 49:1890, 1982. Goodman, S. B.; Bell, R. S.; Fornasier, U. L., et. al.: "Ollier's Disease With Multiple Sarcomatous Transformations," Human Pathology, 15:91, 1984.
Authors: William Enneking, MD; Richard
Rathe, MD; Gene Cornwall, MEd
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