An epithelioid vascular tumour involving a thigh vein mimicking a saphenous nerve lesion: a case report

Abstract

A 34-year-old man presented with progressive, debilitating pain radiating from the distal medial thigh to the medial foot. Magnetic resonance imaging demonstrated a 1 cm enhancing lesion along the expected course of the saphenous nerve. At exploration, the lesion was separable from the nerve but intimately associated with adjacent vessels. Histology demonstrated an intravascular epithelioid endothelial neoplasm, initially interpreted as epithelioid haemangioendothelioma. Supplementary immunohistochemistry favoured epithelioid haemangioma, although classical eosinophil-rich morphology was absent and definitive classification remained uncertain. No molecular testing was performed. Staging showed no distant disease. Multidisciplinary review recommended completion wide excision because the initial procedure was non-oncological and margins were not assessable. Re-excision demonstrated no residual tumour. At latest follow-up, the preoperative pain had settled, with substantially improved residual paraesthesia. This case highlights vascular tumours as rare peripheral nerve mimics and the importance of integrating operative findings, specialist pathology and multidisciplinary management.