Clinicopathological features with outcomes of a series of conventional and proximal-type epithelioid sarcomas, diagnosed over a period of 10 years at a tertiary cancer hospital in India

Abstract

Epithelioid sarcoma (ES) is an uncommon sarcoma. Lately, its variants, including proximal-type ES, have been recognized. The present study highlights clinicopathological features of 26 (65%) conventional and 14 (35%) cases of proximal-type ES. Thirty-eight percent of cases were seen in 21-30-year age group, including 77.5% cases in men. Extremities were the commonest sites in both the subtypes. Histologically, conventional-type ES displayed nodular tumor aggregates with necrosis, while proximal-type showed solid arrangement of large, "rhabdoid-like" cells. More cases (64.2%) of the proximal type were of grade 3. A range of differential diagnoses was considered. Most important immunohistochemical markers were vimentin, epithelial membrane antigen, cytokeratin, CD34, and desmin. Maximum (72.5%) cases were treated surgically. Recurrences and metastasis were observed more in the proximal type. The 7-year disease-free survival was 19.4% in the conventional and nil in the proximal subtype (p = 0.06). The overall survival rate was also lower in the proximal (31.3%) than conventional type (90.2%; p < 0.001). Other unfavorable parameters were deeper location, larger size, and higher tumor stage. This unusual sarcoma, with characteristic growth patterns, merits a proper histological evaluation, as it has many mimics. Proximal-type ES is rather a morphological subtype, associated with an aggressive course.