A Case of Primary Perineural Neuroendocrine Carcinoma of the Urethra

Abstract

This case report presents a 43-year-old female with primary perineural neuroendocrine carcinoma (NEC) of the urethra, an exceptionally rare malignancy accounting for less than 0.5% of urinary tract tumours. The patient presented with dysuria and pain, initially misdiagnosed as a urinary tract infection. Imaging revealed a urethral mass with cystic changes posteriorly, showing heterogeneous enhancement with a characteristic “target sign” on MRI and restricted diffusion on DWI, correlating with high Ki-67 expression (70%). Histopathological and immunohistochemical findings confirmed large-cell neuroendocrine carcinoma. This case provides comprehensive CT and MRI imaging features aiding in early diagnosis and differential diagnosis from more common urethral carcinomas.