Mesonephric adenocarcinoma (MNA) is believed to arise from benign mesonephric remnants or hyperplasia located in the lateral walls of the uterine cervix. They are uncommon in other sites of the gynecologic tract, and exceptionally rare in the uterine corpus. So far, only 30 cases of uterine MNA have been reported in the literature, as a result, the etiology, clinical behavior, choice of treatment, and histogenesis of uterine MNA are still unclear. In this study, we report 2 cases of MNA of uterine corpus. One case involved the inner half of myometrium with endometrial involvement; the second case involved the outer half of myometrium without endometrial involvement. We also reviewed the clinical and pathologic presentations of this rare entity, and discussed the histogenesis of uterine corpus MNA based on recent molecular findings.

Desmoplastic small round cell tumor (DSRCT) is a rare malignant mesenchymal neoplasm that typically affects young patients and presents as large intraabdominal masses. We report a rare case of parotid gland DSRCT in a 38-year-old man. The tumor cells were large sized and form irregular nests embedded in abundant desmoplastic stroma. Immunohistochemically, the tumor cells were positive for cytokeratin, GATA3, p40, and p63. Working differential diagnosis included squamous cell carcinoma, myoepithelial carcinoma, hyalinizing clear cell carcinoma, NUT (nuclear protein of the testis) carcinoma, and adamantinoma-like Ewing sarcoma. The characteristic morphologic features and presence of EWSR1-WT1 gene fusion are diagnostic of DSRCT. Salivary gland DSRCT is an exceedingly rare entity, with only 6 cases reported in the literature.