Background: Adenomatoid tumors (AT) are benign tumor arising from mesothelial lining of organs. Genital tract is the most common site of origin for these tumors. These types of tumors are slow-growing, usually asymptomatic (based on the site of growth) and in consequence they can be spotted many years after their initial growth. Case Report: A 59-year-old man presented with a non-painful nodule arising from the anterior omental cavity. The nodule was excised and morphologically evaluated as adenomatoid tumor of the peritoneal cavity. IHC followed to sustain the diagnosis. Conclusion: Microscopic morphology and tumoral immune-phenotype help to distinguish ATs from well-differentiated adenocarcinomas.