Leiomyo-adenomatoid tumor of the uterus: a distinct morphological entity?

The morphologic and immunohistochemical findings of a well-circumscribed leiomyoadenomatoid tumor located in the posterior uterine wall are reported.

The patient was a 55-year-old white woman who complained of peri/postmenopausal and irregular bleeding during the past 4 months. The adenomatoid component was intermingled with bland smooth muscle fascicles and was composed of vacuolated cells, tubules, and slit-like structures crossed by epithelial bridges. Immunohistochemistry revealed positivity to epithelial and mesothelial markers in the adenomatoid component and strong immunoreaction for smooth muscle markers in the leiomyomatous one.

The well-defined circumscription and the presence of mesothelial component intermingled with the leiomyomatous proliferation favors the hypothesis that a leiomyo-adenomatoid tumor should be considered as a subtype of adenomatoid tumor with distinctive morphological features. Only four previous cases of this rare neoplasm have been reported to date, one in the epydidimis and the other three cases in the uterine wall, one of them affecting also to the right ovary.