A Case Report of an Adenomatoid Tumor of the Fallopian Tube: The Histopathologic Challenges and a Review of the Literature.

: Adenomatoid tumor (AT) is a rare benign neoplasm of mesothelial origin, which mainly occurs in the male and female genital tracts. The most common site for AT occurrence in women is the uterus, which makes the presentation in the fallopian tube(s) a rarity with an incidence of approximately 0.5%. The reported extragenital sites include serosal surfaces, adrenal glands, and visceral organs, are even less common. Macroscopically, ATs present as white-grayish or yellowish irregular yet circumscribed firm nodules, often containing cystic components. Owing to a vast array of histomorphological growth patterns, ATs tend to mimic malignancy and trigger overresection. Such clinical situations have been described by several studies for the ovaries, uterus, and fallopian tubes, underlining the importance of differential diagnosis in order to avoid superfluous treatment. : Herein, we report a presentation of an AT at the oviductal lumen, detected incidentally during prophylactic bilateral salpingo-oophorectomy in a 67-year-old patient with a BRCA1 mutation. : Immunohistochemical staining revealed a positive expression for calretinin, WT1, and cytokeratin 7, and negative expression for both PAX8 and CD34, thus confirming the diagnosis of AT and excluding tubal malignancy. : This report, with a concise review of the global literature on tubal AT, brings attention to the solitary and asymptomatic nature of the tumor. With a clear diagnosis, no surgical radicality is necessary.