Combined Undifferentiated and Neuroendocrine Carcinomas of the Gallbladder Appearing as Two Separate Lesions: A Case Report with Radiological-Pathological Correlation.

We report herein a rare case of incidentally detected combined undifferentiated and neuroendocrine carcinomas of the gallbladder. An incidental gallbladder malignancy was revealed on abdominal ultrasound and multi-detector computed tomography in a 54-year-old man. A short distance from the main polypoid hypoechoic mass at the fundus of the gallbladder, focal wall thickening was noted with prominently increased power Doppler flow. Extended cholecystectomy was performed, and histology confirmed the main polypoid mass as undifferentiated carcinoma and the separate nodule as neuroendocrine carcinoma. To our knowledge, this is the first report presenting two separate lesions of combined gallbladder carcinomas by radiological features.