Extraskeletal myxoid chondrosarcoma: A clinicopathologic, immunohistochemical, and molecular analysis of 18 cases

S. Okamoto et al., Extraskeletal myxoid chondrosarcoma: A clinicopathologic, immunohistochemical, and molecular analysis of 18 cases, HUMAN PATH, 32(10), 2001, pp. 1116-1124
Citations number
Categorie Soggetti
Research/Laboratory Medicine & Medical Tecnology","Medical Research Diagnosis & Treatment
Journal title
ISSN journal
0046-8177 → ACNP
Year of publication
1116 - 1124
SICI code
Extraskeletal myxoid chondrosarcoma, (EMCS) is an uncommon clinicopathologi cally well-defined tumor, but its pathogenesis and biologic behavior are po orly understood. We reviewed 18 cases of EMCS to verify clinicopathologic f eatures and immunohistochemical profiles together with molecular detection of the tumor-specific fusion genes. The tumors were located mainly in the p roximal extremities and limb girdles (72%). Two tumors arose at unusual ana tomic sites: the finger and the hip joint. Nine of the 17 followed-up patie nts were alive and disease free, 4 were alive with recurrences and/or metas tases, and 4 died of the tumor. Fifteen tumors showed typical features of E MCS, and 3 had hypercellular areas in addition to conventional EMCS areas. The tumors were variably immunoreactive for S-100 protein (50%), NSE (89%), peripherin (60%), and synaptophysin (22%). Chromogranin A and some epithel ial markers (AE1/AE3, CAM5.2, and epithelial membrane antigen) were entirel y negative. Frequent expressions of the neural/neuroendocrine markers sugge st possible neural/neuroendocrine differentiation in at least some EMCSs, i n addition to chondroid differentiation. In a reverse-transcription polymer ase chain reaction (RT-PCR) assay using paraffin-embedded specimens, EWS-CH N or TAF2N-CHN fusion gene transcripts characteristic of EMCS could be dete cted in 15 (83%) of the 18 cases: EWS-CHN type 1 in 11 cases, EWS-CHN type 2 in 1, and TAF2N-CHN in 3. Three fusion-negative cases included 2 conventi onal EMCSs and I considered a "cellular" variant of the tumor. None of 30 o ther soft tissue and bone tumors with myxoid or chondroid morphology that w e examined contained these fusion genes. Thus, RT-PCR detection of EWS-CHN or TAF2N-CHN fusion gene using archival paraffin-embedded tissue is a feasi ble and useful ancillary technique for the diagnosis of EMCS. Hum PATHOL 32 :1116-1124. Copyright (C) 2001 by W.B. Saunders Company.