Primary Small Cell Neuroendocrine Tumour of Gallbladder Presenting as Pyrexia of Unknown Origin

Herein, we report a case of primary small cell neuroendocrine tumor (NET) of the gallbladder in a 45-year-old female who presented with complaints of fever accompanied by abdominal pain on the right upper quadrant for one month. Contrast-enhanced computed tomography abdomen showed a large gallbladder mass. It was infiltrating the segments IVa, IVb, and V of the liver. Ultrasound-guided fine-needle-aspiration-cytology was performed. Based on preoperative pathological and immunohistochemical investigations, it was diagnosed to be a primary small cell NET of the gallbladder. The patient underwent radical cholecystectomy after three cycles of cisplatin-based neoadjuvant chemotherapy. She had an uneventful recovery and received adjuvant chemo-radiotherapy. The patient was well at the 18-month follow-up.