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Case Reports
. 2019 Sep 27;13(3):410-417.
doi: 10.1159/000503169. eCollection 2019 Sep-Dec.

Combined Intestinal Adenomas/Microcarcinoids

Hiromi Tamura  1 , Hiroka Ando  1 , Reiko Doi  1 , Shiro Adachi  1
Affiliations
Case Reports

Combined Intestinal Adenomas/Microcarcinoids

Hiromi Tamura et al. Case Rep Gastroenterol. .

Abstract

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.

Keywords: Carcinoid; Combined intestinal adenoma-microcarcinoid; Large intestine; Microcarcinoid; Neuroendocrine tumor.

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Conflict of interest statement

The authors have no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Endoscopic views of case 1 (a) and case 2 (b). Both cases exhibited well-circumscribed and slightly elevated lesions.
Fig. 2.
Fig. 2.
a Low-power view of the polyp of case 1 reveals an adenomatous structure with a barely recognizable microcarcinoid component (black arrows). b Higher-power view reveals nests and cords of endocrine cells connected to adenomatous glands. c Immunohistochemical staining for synaptophysin reveals diffuse cytoplasmic reactivity of the microcarcinoid component only. d The nuclei were strongly immunoreactive for β-catenin.
Fig. 3.
Fig. 3.
a Low-power view of the polyp of case 2 reveals an adenomatous structure with a barely recognizable microcarcinoid component (black arrows). b Although, at a glance, the structure seems to be a squamous morula, the cytoplasmic granularity characteristic of neuroendocrine differentiation is evident. c The microcarcinoid components are weakly positive for synaptophysin. d The nuclei of the microcarcinoid components are much more strongly immunoreactive for β-catenin than those of the adenomatous components.
See this image and copyright information in PMC

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