Penile Epithelioid Hemangioma with Atypical Features Harboring a Novel FOS::ERG Fusion

Epithelioid vascular neoplasms span a wide spectrum from benign hemangiomas to malignant angiosarcomas, creating significant diagnostic challenges due to overlapping histopathologic features. We present the case of a man in his 40's with a 1.5 cm painless, well-circumscribed mass on the dorsum of the base of penis. Microscopically, it corresponded to an epithelioid vascular neoplasm with cytologic atypia, necrosis and noticeable mitotic activity. A conservative surgical approach was undertaken, and the local excision specimen revealed an ​epithelioid hemangioma with a novel FOS::ERG fusion. This first reported atypical epithelioid hemangioma harboring a FOS::ERG fusion highlights the importance of integrating clinical, histopathologic, and molecular findings to avoid misinterpretation of these indolent neoplasms as sarcoma. Recognizing this ​benign mimicker of malignancy is essential to prevent an unnecessary radical surgery.