The following is a summary of “Primary Epithelioid Sarcoma of the Conchal Bowl in a 64-Year-Old Male: A Case Report and Review of the Literature,” published in the June 2023 issue of Dermatopathology by Li et al.
Epithelioid sarcoma (ES) is a malignant mesenchymal neoplasm characterized by atypical epithelioid cells palisading around a necrotic central zone. Even within soft tissue pathology, ES is a rare entity. Immunohistochemical examination of malignancies typically reveals diffuse expression of epithelial membrane antigen and cytokeratin and loss of nuclear INI1 (SMARCB1) expression.
Here, researchers present the case of a 64-year-old man with a left conchal bowl ES. This patient was misdiagnosed with basal cell carcinoma and treated with topical imiquimod at an outside facility due to his age, sun-exposed skin, and small, asymptomatic, pink crystalline papule. Despite the treatment, the lesion grew and eventually manifested symptoms, after which a biopsy was performed.
Despite the patient’s age and atypical anatomic location, the microscopic and immunohistochemical findings were typical of conventional-type ES. Their case demonstrates that ES can arise in uncommon sites and older individuals, where it is more likely to be clinically and pathologically misdiagnosed as a nonmelanoma skin cancer.