Diffusely infiltrating endometrial carcinomas with no stromal response: report of a series, including cases with cervical and ovarian involvement and emphasis on the potential for misdiagnosis.

Endometrial carcinomas, particularly of endometrioid type, can invade the myometrium or cervix without eliciting a stromal desmoplastic or inflammatory response and have been referred to as diffusely infiltrating endometrial carcinomas. This study describes a series of 14 endometrial carcinomas infiltrating as single "naked" glands without a stromal response. The neoplasms consisted of 12 endometrioid carcinomas, 1 mixed endometrioid and clear cell carcinoma, and 1 serous carcinoma. In all cases, there was myometrial invasion without stromal response. Seven cases exhibited cervical stromal involvement and in 2 there was involvement of both ovaries in a similar pattern. Several of the cases were seen in consultation and the pattern of infiltration raised a number of differential diagnoses, both benign and malignant, depending on the site of tumor involvement, including adenomyosis, adenomyoma, primary endocervical glandular lesions, cervical mesonephric remnants, endometriosis or tuboendometrioid metaplasia, and ovarian cortical inclusion cysts. Although this pattern of invasion has been reported previously, it continues to present diagnostic difficulties.