Synovial sarcoma: an Australian series of 48 cases.

A series of 48 cases of synovial sarcomas submitted to the Australasian Soft Tissue Tumour Registry between 1965 and 1980 is reported. Tumours were analysed with regard to clinical features, morphology and outcome. The overall 5-yr survival rate for all assessable cases was 50%. A strong relationship between size and survival was noted with a 73% 5-yr survival rate where tumours were less than 5 cm in maximum diameter. Biphasic tumours (16 cases) appeared to have a better prognosis, with a mean survival time of 6.1 yr as compared with 4 yr for monophasic tumours (32 cases); however, the former were generally slightly smaller tumours. Tumours with less than 5 mitoses per 10 highpower fields (2.8 sq mm) had double the mean survival time of other tumours. The histological features of swirling architecture, monotonous cell type, vascular pattern, myxoid foci, collagen production, mast cell presence and calcification are recommended as cumulative factors in arriving at a diagnosis where a biphasic pattern is not apparent.