Uncommon pattern in soft tissues epithelioid sarcoma

Epithelioid sarcoma (ES) is a rare tumor, but extremely versatile, simulating easily both clinically and morphologically multiple benign lesions as granulomas and malignant tumors as achromic melanomas or carcinomas. Especially the histological aspects are suggesting for an epithelial tumor. The atypical biological behavior of tumor is conferred by: a propensity for lymph nodes metastases, large dimensions of tumor, unusual localizations.

To report some peculiar histological and immunophenotypic aspects in soft parts epithelioid sarcoma.

We analyzed retrospectively three cases of epithelioid sarcomas with unusual clinico-morphological (large dimensions), histopathological (absence of necrosis) and immunohistochemical (IHC) patterns selected from 200 consecutive soft parts malignant tumors of "Victor Babeş" National Institute Bucharest files. For the immunohistochemical (IHC) staining, the following antibodies were used: vimentin, EMA, cytokeratins (KL1, CK19), S-100 protein, CD68, p53 protein, vascular markers (CD31, CD34, FVIII-related antigen), HMB45, MELAN A.

The tumors had unusually large dimensions, the absence of necrosis, a vaguely alveolar pattern; the IHC staining showed a strong positivity of S-100 protein, a variable expression of cytokeratins KL1 and CK19, in association to a scarce positivity for EMA, zonal positivity for CD34 and diffuse reaction for vimentin.

The immunophenotype of ES may have a large variability and the correlation to clinico-morphological aspects is necessary for a good diagnostic assessment.