Carcinosarcoma of the uterine cervix: a report of eight cases with immunohistochemical analysis and evaluation of human papillomavirus status.

Carcinosarcomas (malignant Müllerian mixed tumors [MMMTs]) of the uterine cervix are rare neoplasms. This report describes the morphology, immunohistochemical profiles, and human papillomavirus (HPV) status of eight cervical MMMTs. Patients' ages ranged from 32 to 93 years (mean, 61 years). Seven cases showed in situ squamous cell carcinoma (SCC). The invasive epithelial component (EC) was composed of combined adenoid basal carcinoma, basaloid SCC, and adenoid cystic carcinoma (ACC) in two cases. Keratinizing SCC, large cell nonkeratinizing SCC, undifferentiated carcinoma, and basaloid SCC predominated in the remaining tumors, one of which had admixed ACC. The sarcomatous component (SC) was homologous and spindled with admixed myxoid areas in three lesions. The ECs and SCs in six MMMTs showed dual immunostaining with epithelial membrane antigen and the pan-keratin marker, MNF116. The SC was vimentin-positive in seven cases. Five tumors had a vimentin-positive EC. The SC was positive for muscle specific actin and/or smooth muscle actin in seven lesions, of which four were desmin-positive. Polymerase chain reaction (PCR) using GP5+/GP6+ L1 consensus primers detected HPV DNA in all eight cases. Nonisotopic in situ hybridization with digoxigenin-labeled probes to HPV types 6, 11, 16, 18, 31 and 33 demonstrated integrated HPV 16 in three cases, not only in the EC, but also in nuclei of the SC. This is the first study to implicate HPV in the evolution of cervical MMMTs. The above observations lend support to a metaplastic theory of histogenesis.