Mixed neuroendocrine-non-neuroendocrine neoplasm of the gallbladder concomitant with sarcomatoid component revealing a unique form: A case report

Abstract

A 72-year-old man was referred to our department owing to the wall thickening of the gallbladder. CT and MRI revealed nodular and wall thickening lesions. EUS indicated tumor invasion to a layer of the subserosa. The bile juice cytology revealed adenocarcinoma. Extended cholecystectomy was performed; the resected specimen showed a mucosa with irregular surface and a separated fragment. Moreover, pathological findings of the fundus of the gallbladder revealed a tubular adenocarcinoma and a neuroendocrine carcinoma. Furthermore, the histological findings of a separated fragment revealed adenocarcinoma with sarcomatoid tissue. Finally, this lesion was diagnosed as a mixed neuroendocrine-non-neuroendocrine neoplasm with a sarcomatoid component. The complicated histological component may be the cause of the unique form.