Cytological diagnosis of Brunner's gland adenoma (hyperplasia): A diagnostic challenge.

Brunner's gland adenoma (hyperplasia) (BGA/H) is a benign gastrointestinal lesion, usually asymptomatic and frequently detected incidentally by endoscopy as a submucosal nodule. Most BGA/Hs are diagnosed by their typical cytological morphology and immunohistochemical features, characterized by monomorphic cells arranged as loosely clusters of epithelial cells with abundant, clear, and granular cytoplasm, eccentrically located nuclei, and immunoreactivity for MUC-6. The combination of the clinical and pathological features is essential for rendering a correct diagnosis. Herein, we report two cases of BGA/H, including their cytologic and histologic features, and a literature review of the clinicopathologic findings along with its differential diagnoses.