Extensive squamous metaplasia (morulosis) of the endometrium as a clinical and pathological problem: a case report and literature study.

The article presents a case of a 28-year-old woman with so-called morulosis - a form of squamous metaplasia of the endometrium, which may mimic malignancy. The term 'morulosis' indicates extensive squamous mulberry-like metaplasia, which in a large part or nearly entirely affects endometrium, whereas in turn, benign squamous metaplasia or single morules, refers to a limited, usually small regional pathology of endometrium. Because the endometrial glands and stroma gradually undergo the process of squamous metaplasia, in a scanty biopsy material the picture may lead to overdiagnosis. In the epithelioid regions small inactive glands with an immunofenotype different from the remaining endometrium might be observed. So far 21 cases have been reported in English literature. The patients (age 19-45) had presented with abnormal bleeding, infertility or after hormonal therapy. The mechanism of the extensive squamous metaplasia of endometrium is still not clear. The prevailing view holds that morulosis appears to be a result of hormonal imbalance. To shed light on possible pathogenic background of morulosis, we present a case of particularly severe extensive squamous metaplasia of the endometrium (morulosis).