Atypical forms of microglandular hyperplasia of the cervix simulating carcinoma. A report of five cases and review of the literature.

We report five cases of microglandular hyperplasia with unusual histologic features. The diagnosis of carcinoma--usually clear cell adenocarcinoma--was seriously entertained in all the cases. Three of the patients were premenopausal; two were postmenopausal. Two of them were on oral contraceptives; one was on estrogen and progesterone replacement therapy. The histologic features that caused diagnostic difficulty were: a solid, sheet-like proliferation of cells (four cases), a pseudoinfiltrative pattern (one case), abundant stromal hyalinization (one case), signet ring cells (two cases), hobnail cells (two cases), and the presence of moderate degrees of nuclear atypicality (two cases) and occasional mitotic figures (two cases). However, foci with these features usually merged with areas of typical microglandular hyperplasia. After conservative therapy in four cases, follow-up of up to 12 years has been unremarkable. It is important for pathologists to be aware of these unusual histologic appearances of microglandular hyperplasia to avoid its misinterpretation as a malignant tumor.