Uterine superficial serous carcinomas and extensive serous endometrial intraepithelial carcinomas: clinicopathological analysis of 6 patients.

Uterine superficial serous carcinoma (SSC) and serous endometrial intraepithelial carcinoma (SEIC) are unique malignancies found primarily in postmenopausal women. SSC and SEIC lesions measuring 1 cm or less are categorized as minimal uterine serous carcinoma (MUSC). Less well understood, however, the clinical behavior of SSC and SEIC lesions measuring more than 1 cm. We investigated 6 postmenopausal patients, aged 69-83 years, with SSC or SEIC and without hyperestrogenism. All but 1 patient had tumors originating from the surface of polyps, including 3 patients who each had an enormous polyp occupying the entire uterine cavity. Two patients had extensive SEICs measuring more than 1 cm; the others had SSCs, including 1 MUSC. The mesenchymal cells of the cancer-bearing polyps lacked the morphologic characteristics of endometrial stroma, and the cancer glands often immunostained negatively for estrogen receptors and progesterone receptors. Diffuse immunostaining for human epidermal growth factor receptor 2 was detected in 3 patients, and p53 was detected in all. Cyclin E, a downstream molecule of the F-box and WD repeat domain-containing 7 (FBXW7), was detected in all patients. Microdissected cancer glands showed p53 mutations in 2 patients and a FBXW7 mutation in 1 patient. These findings suggest that mutations of FBXW7 and p53 may contribute to the carcinogenesis of less invasive tumor subtypes. Pathologists and physicians should carefully evaluate SSC and SEIC lesions involving large polyps but lacking myometrial invasion.