[Primary ovarian squamous cell carcinoma: clinicopathological features and prognostic analysis of fifteen cases]

Objective: To assess the clinical features and treatment outcomes in patients with primary ovarian squamous cell carcinoma (POSCC). Methods: Fifteen patients with primary ovarian squamous cell carcinoma diagnosed from January 2009 to December 2018 in Cancer Hospital of the University of Chinese Academy of Sciences were collected. The expression of p16, hMLH1, hMSH2, hMSH6 and PMS2 in POSCC was detected by immunohistochemistry, and the status of high-risk human papillomavirus (HPV) by RNAscope test. Results: Squamous cell carcinoma with different degrees of differentiation was found in 15 cases, including three cases with high differentiation and 12 cases with medium to low differentiation. There were four cases with in situ squamous cell carcinoma, four cases with teratoma, one case with endometrial carcinoma/atypical hyperplasia, and one case with endometriosis. p16 was expressed in five cases (5/15), indicating coexisting high-risk HPV infection. There was no high-risk HPV infection in the remaining 10 cases, and p16 staining was negative. There was no deficient mismatch repair protein in all cases. The overall survival time (P=0.038) and progression free survival (P=0.045) of patients with high-risk HPV infection were longer than those without HPV infection. Conclusions: POSCC is more commonly noted in postmenopausal women and often occurs unilaterally. Elevated serological indexes CA125 and SCC are the most common finding. Morphologically, the tumors show variable degrees of differentiation, but the current data suggest that the degree of differentiation cannot be used as an independent prognostic index. High-risk HPV infection may be associated with the occurrence of POSCC, and that the prognosis of POSCC patients with HPV infection is better than that of patients without infection.