Combined Intestinal Adenomas/Microcarcinoids

The combined colonic adenoma/microcarcinoid tumor is a rare intestinal neoplasm featuring intermingled adenomatous and carcinoid components. A few case reports and small case series have suggested that this entity exhibits an indolent clinical course. Here, we report two cases with these tumors, and describe the morphological features and clinical follow-up. A 61-year-old male and 78-year-old male presented with heme-positive stools at their medical checkups. Colonoscopy revealed masses in the colons; we performed endoscopic mucosal resection. Both lesions featured low-grade adenomas and low-grade neuroendocrine tumors. We diagnosed combined colonic adenomas/microcarcinoids. The clinical courses of both patients were benign at follow-up at 2.5 and 6 years. Awareness of this rare colonic tumor should prevent potential diagnostic pitfalls and may help clarify the natural history of these tumors and their possible relationships with composite glandular/carcinoid tumors.