Mesonephric adenocarcinoma (MA) is a rare tumor of the female genital tract, mainly in the cervix and vagina, which is usually associated with mesonephric remnants or mesonephric hyperplasia. In the uterus corpus, MA is as rare as mesonephric structures, and only a few cases have been previously reported. Here, we report a rare case of MA of the uterine corpus. A 73-year-old woman presented with multiple nodules in the bilateral lung. Abdominal computed tomography scan confirmed a uterine tumor measuring 8.6 cm. All tumor markers, including CA125, were within normal limits. A total hysterectomy and bilateral salpingo-oophorectomy were performed. The tumor was confined to the myometrium and showed strong resemblance to cervical MA despite the absence of mesonephric hyperplasia or remnants. The most striking pattern consisted of large sheets of small round tubules, often with densely eosinophilic secretions in the lumen. In addition, the ductal pattern simulating endometrioid adenocarcinoma was also noted. A mixture of tubular and ductal patterns, most predominantly seen, formed more complex tubules and cribriform structures. Other elements consisted of a retiform pattern, serous adenocarcinoma-like papillary budding, and glomeruloid morphology. Immunohistochemically, the tumor cells were positive not only for cytokeratin, epithelial membrane antigen, and vimentin but also for CD10 and calretinin. No staining was identified for estrogen receptor, progesterone receptor, or androgen receptor. Adjuvant chemotherapy was begun for the patient, who is alive with disease 28 months later. We review the previously published cases of MA and discuss the principal differential diagnosis of MA in the uterine corpus.