Section 11
Chapter 10,788

Identification of poorly differentiated synovial sarcoma: A comparison of clinicopathological and cytogenetic features with those of typical synovial sarcoma

de Silva, M.V.C.; McMahon, A.D.; Paterson, L.; Reid, R.

Histopathology 43(3): 220-230


ISSN/ISBN: 0309-0167
PMID: 12940774
DOI: 10.1046/j.1365-2559.2003.01668.x
Accession: 010787637

Download citation:  

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.

PDF emailed within 0-6 h: $19.90