Abstract

Epithelioid sarcoma (ES) is an uncommon malignant mesenchymal neoplasm with poorly understood histogenesis and associated SMARCB1 deletion often presenting on the skin. These tumors may present as a slow growing dermal or subcutaneous nodule on the extremities and show frequent local recurrence or metastasis. Here we present a 41-year-old male with a remote history of diffuse large B-cell lymphoma with testicular involvement treated with chemotherapy and scrotal irradiation, who presented with neurological symptoms and was found to have recurrent lymphoma with CNS involvement. During hospitalization, PET CT imaging noted possible scrotal involvement. Skin examination discovered an ulcerated scrotal nodule and a punch biopsy was performed.  Microscopic examination demonstrated atypical epithelioid to spindled cells with a haphazard to fascicular growth pattern involving the dermis. Tumor cells showed positive immunostaining with vimentin, cytokeratin AE1/3, CAM5.2, EMA, ERG, SMA, and focal CD34. The tumor also demonstrated nuclear INI-1 (SMARCB1) loss and retained BRG1 (SMARCA4) nuclear expression.  The morphologic features and immunoprofile were consistent with conventional ES. Excision demonstrated 1.4 cm residual ES limited to the dermis. The patient has no evidence of metastatic disease. Few associations have been made with the possible pathogenesis of ES, although prior trauma has been noted in a subset of cases. In our case, the patient received radiation to this region eight years preceding the diagnosis. This association, to our knowledge, has not been previously described in the literature. We present this case as well as a review of the literature regarding etiologic associations with ES.