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.
Keywords Epithelioid sarcoma - Proximal-type epithelioid sarcoma - Uncommon sarcomas