Primary squamous cell carcinoma of the endometrium: case history, pathologic findings, and discussion.

Primary squamous cell carcinoma of the endometrium (PSCCE) is an exceedingly rare tumor. Rarely are cytological criteria discussed. We report our experience in the cytological diagnosis of a case. A postmenopausal, 64-yr-old woman suffered from pyometria. An endometrial Pap smear displayed some malignant squamous cells. Curettage of the cervix and the uterine cavity only recovered some fragments of atypical squamous epithelium whose origin could not be precisely identified. A hysterectomy with bilateral adnexectomy was decided upon. Pathological study evidenced a primary squamous cell carcinoma in the uterine cavity while the cervix was tumor-free and the lymph nodes were devoid of metastases (pT1, pN0, pM0). The patient died 46 mo PO with multiple pulmonary and renal metastases. The histological feature of PSCCE is identical to that of any tumor of a similar nature, whatever the site, especially the cervix. Confirmation of the primary endometrial nature is only possible on the hysterectomy specimen.