Endometrial stromal sarcomas (ESSs) are morphologically heterogenous and diagnosed by light microscopy in most instances. The distinction between smooth muscle neoplasms, such as cellular leiomyoma and low-grade ESS can be problematic. The diagnoses of ESS on the basis of systematic assessment of gross and histological parameters are highlighted.Hysterectomy from four patients for a clinical diagnosis of leiomyoma was studied. Grossly, three had polypoidal lesion and in one myometrial widening with obvious permeation was noted. Microscopy showed features of ESS in three cases. Other case was diagnosed as cellular leiomyoma thought to be endometrial polyp. Reticulin stain was employed to highlight the characteristic spiral arterioles in ESS and thick-walled vessels in cellular leiomyoma.

Up to a quarter of ovarian masses originate from germ cells and many of these are mature cystic teratomas (MCT). The secondary development of malignancy is a rare but well-known phenomenon in patient with ovarian teratomas. The incidence of malignant transformation in mature cystic teratoma of the ovary is less than 2% as reported in gynecological and pathological literature. Here, we present a case of malignant transformation in MCT of the ovary.