Atypical Epithelioid Schwannoma in a Young Female- A Dilemma Set by Morphology; Resolved by Immunohistochemistry-A Rare Case Report

Epithelioid morphology spawns myriad of benign and malignant tumors into differential diagnoses, which include epithelioid sarcoma, malignant melanoma, epithelioid malignant peripheral nerves sheath tumor, epithelioid hemangioendothelioma, myoepithelioma, etc. Epithelioid schwannoma (ES), especially the atypical variant has not received much attention in literature. Conclusive diagnosis, important for accurate management is, however, challenging. We describe a case of atypical ES in a 24-year-old female. On clinical and radiological examination, a provisional diagnosis of vascular malformation was made. Atypical epithelioid ESs are rare, but it is important to be aware of this variant to avoid misdiagnosis with other malignant epithelioid tumors. Apart from clinical and morphological features, immunohistochemistry aids in arriving at a decisive diagnosis. Perineurium-like capsule, circumscription, oblong shape of the lesion, and hyalinized blood vessels are pointers toward shwannomatous differentiation of this tumor.