A Case of Cecal MiNEN (Mixed Adenocarcinoma-neuroendocrine Carcinoma)

Abstract

A 77-year-old woman presented with epigastric pain. Computed tomography showed an irregular cecal mass, ileocecal lymphadenopathy, and small intestinal dilation. Colonoscopy showed an irregular ulcerative tumor in the cecum and ascending colon, and a subsequent biopsy specimen revealed it to be moderately differentiated tubular adenocarcinoma. She was diagnosed with intestinal obstruction secondary to cecal cancer (cT3N2M0, cStage III) and underwent right hemicolectomy. The resected specimen was an irregular ulcerative tumor (11 × 10 cm). Histopathological evaluation showed well-differentiated tubular adenocarcinoma (tub1) in the mucosa and submucosa at the tumor periphery, while the central, muscular, and subserosal components of the lesion were identified as neuroendocrine carcinoma (NEC). In view of the fact that the tub1 and NEC components each occupied > 30% of the tumor (pT3, INFc, ly1b, v1b, N2a [metastatic NEC], Stage IIIb), the lesion was diagnosed as MiNEN, mixed adenocarcinoma-NEC. She received postoperative adjuvant chemotherapy with carboplatin and irinotecan ; however, 8 months postoperatively, she developed multiple liver metastases with hepatic hilar lymphadenopathy and died 11 months postoperatively. Although colorectal mixed adenocarcinoma-NEC is rare, case accumulation and development of effective chemotherapy are needed to improve its prognosis.