Fibrolipomatous Hamartoma of a Peripheral Nerve in the Groin of a Child: A Rare Case Report

Abstract

Fibrolipomatous hamartoma of the nerve, also termed lipomatosis of the nerve, is a rare benign tumor characterized by fibrofatty infiltration of peripheral nerves. It most commonly affects the median nerve in the upper extremities, while involvement of other anatomical sites is uncommon. Groin involvement has rarely been reported and may present diagnostic challenges because groin masses in children are usually attributed to more common conditions. A 1-year 9-month-old boy presented with a painless left groin mass that had slowly enlarged over six months. Physical examination revealed a firm, non-tender mass approximately 2 cm in diameter, situated separate from the testis. Ultrasonography demonstrated a heterogeneous hyperechoic lesion within the left inguinal canal, with interval growth compared to previous imaging. Magnetic resonance imaging showed asymmetric thickening of the subcutaneous fat partially surrounding the spermatic cord. Surgical exploration was performed for diagnosis. The mass was partially attached to the distal spermatic cord and located near the urethra. Histopathological examination revealed benign adipocytic tissue with entrapped nerve bundles, consistent with fibrolipomatous hamartoma. Fibrolipomatous hamartoma of the nerve is an extremely rare cause of pediatric groin mass. This condition should be considered in the differential diagnosis of lipomatous lesions in the groin. When imaging findings are inconclusive, surgical biopsy or excision may be considered to establish the diagnosis and exclude other tumors.