A CASE OF NEUROENDOCRINE CARCINOMA OF THE TRANSVERSE COLON THAT HAD TRANSFORMED FROM ADENOCARCINOMA

Abstract

A 55-year-old Japanese man was admitted to our hospital due to diarrhea, stomachache, hepatomegaly, and abnormal liver function findings. Colonoscopy revealed a tubulovillous adenoma (IIa) of approximately 4-5 cm in diameter in the transverse colon. Diffuse uptake of FDG in the liver and uptake in the colon tumor were detected by FDG-PET/CT, after which the tumors in the liver were diagnosed as neuroendocrine carcinoma (NEC) based on biopsy findings. His general condition rapidly worsened and the patient died 24 days after admission. Autopsy findings showed that the colon tumor was a mixture of adenocarcinoma and adenoma with partial transformation from adenocarcinoma to NEC. When there is a dissociation between findings on digestive endoscopy and those on other imaging modalities, partial transformation from adenocarcinoma to NEC should be considered.