ATYPICAL POLYPOID ADENOMYOMAS OF THE UTERUS

We performed a clinicopathological immunohistochemical, ultrastructura l, and flow cytometric study on six cases of atypical polypoid adenomy oma of the uterus including one with an adenocarcinoma within it, The tumours occurred in nulliparous women aged 22-48 years (average, 33.0 years); three arose in the uterine corpus, and three in the endocervix , Histologically, they were composed of endometrial glands admired wit h a stromal component of interlacing bundles of smooth muscle cells, T he glands exhibited varying degrees of architectural and cytological a typia, Most of the stromal cells showed strong staining for HHF35, alp ha-smooth muscle actin, and vimentin, and some cells contained desmin. Electronmicroscopy, in one case, confirmed the presence of a well-dif ferentiated smooth muscle component, The stromal component may arise a s a result of extensive metaplasia of endometrial stromal cells. Uninv olved endometrium showed ciliated cell metaplasia in three patients, a nd atypical complex hyperplasia in two. One patient had a well-differe ntiated adenocarcinoma of endometrioid type arising in an endocervical atypical polypoid adenomyoma. All tumours had a diploid DNA content a nd relatively small S phase fraction (average, 6.23%), The follow-up p eriods ranged from 4 to 42 months (average, 13.5 months), and all pati ents were alive and well, Although the histogenesis of atypical polypo id adenomyoma of the uterus remains uncertain, it is suggested that it may arise because of oestrogen-related factors.