Uterus-Like Mass with Features of an Extrauterine Adenomyoma: A Case Report and Literature Review

Kim, Mi Jin; Seok, Sang Hee

Abstract

Uterus-like masses, such as cavities lined by endometrium-type mucosa surrounded by bundles of smooth muscle cells, may strikingly resemble the uterus. In this report, we describe a case of a uterus-like mass with features of an extrauterine adenomyoma in a 42-year-old woman. The first uterine-like mass was documented by Cozzutto in 1981 and to date, 13 such cases have been reported. Three theories have been offered to explain their etiology: 1) the uterine/Mullerian duct fusion defect theory, which is based on a developmental abnormality occurring during the formation of the female genital tract, 2) the metaplastic theory, which is based on the fact that a uterus-like mass may arise from subperitoneal mesenchymal cells that retain the ability to duplicate Mullerian duct structures, and 3) the heterotopia theory. We consider that the metaplastic theory best fits with our observations in the present case as both glandular and stromal smooth muscle cells proliferated as a true neoplasm rather than as an anomaly.