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Identification of poorly differentiated synovial sarcoma: a comparison of clinicopathological and cytogenetic features with those of typical synovial sarcoma
Author(s) -
De Silva M V C,
McMahon A D,
Paterson L,
Reid R
Publication year - 2003
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1046/j.1365-2559.2003.01668.x
Subject(s) - synovial sarcoma , pathology , sarcoma , chondrosarcoma , biology , calcification , hyaline , medicine
Aims: Poorly differentiated areas in synovial sarcomas (SS) are known to be associated with a poorer prognosis. The aim of our study was to describe the morphological spectrum of poorly differentiated synovial sarcomas (PDSS) and refine the criteria for their recognition. Methods and results: The clinicopathological features of 28 PDSS were compared with those of 26 classic SS. Common cell types in PDSS included epithelioid, spindle and Ewing sarcoma‐like small round cells. Unusual features included presence of desmoplastic small cell tumour‐like areas and extraskeletal myxoid chondrosarcoma‐like areas. The presence of necrosis ( P = 0.002), a mitotic rate over 10/10 high‐power fields ( P < 0.001), a haemangiopericytomatous vascular pattern ( P < 0.001) and vascular invasion ( P = 0.003) were significantly associated with PDSS, while mast cells ( P < 0.001), calcification ( P < 0.001) and hyaline bands ( P < 0.001) were significantly associated with classic SS. Poorly differentiated areas showed increased proliferative activity with Ki67. PDSS showed a tendency to be larger ( P = 0.008) and to be located in proximal more than distal sites ( P = 0.025). Three entirely poorly differentiated tumours were diagnosed by demonstration of the t(X;18)(p11;q11) translocation. PDSS showed additional cytogenetic abnormalities. Conclusions: Poorly differentiated synovial sarcomas show a spectrum of histological features, which may simulate other malignant neoplasms. The diagnosis of entirely poorly differentiated synovial sarcomas requires cytogenetic analysis.