Primary Vaginal Neuroendocrine Carcinoma: Case Report and Literature Review.

Primary small cell carcinoma of the vagina (SmCCV) is exceptionally rare, and its presentation often mimics metastatic disease from more common sites, making diagnosis difficult. In this report, we describe an older woman who came to medical attention with new vaginal bleeding, leading to the discovery of a large vaginal mass. Biopsy findings and whole-body imaging, including positron emission tomography/computed tomography (PET/CT), ultimately supported a primary vaginal origin despite the presence of extensive metastases. Her case illustrates how unusual and clinically challenging this tumor can be, and it emphasizes the need for close collaboration between clinical evaluation, imaging, and pathology to recognize this aggressive malignancy promptly.