p16-negative warty carcinoma of the uterine cervix with superficial invasion to the endometrium: A case report focusing on diagnostic pitfalls

Abstract

Warty carcinoma of the uterine cervix is a very rare and specific variant of invasive squamous cell carcinoma, usually described as a hybrid of the features of both condyloma acuminatum and invasive squamous cell carcinoma. The diagnostic pitfalls of this lesion are: 1) the bland appearance of cytomorphology, 2) distinct koilocytotic atypia, and 3) p16 negativity. A case of warty carcinoma with a fungating mass on the uterine cervix of a 75-year-old woman is presented. The original diagnosis by punch biopsy was atypical squamous cells, undetermined for malignancy, adjunct with p16 negativity. The subsequent radical hysterectomy showed a protruding mass (5.7 cm in horizontal dimension) of the uterine cervix. Light microscopy revealed a protruding mass composed of exophytic papillae and inverted nests along the endocervical glands. There were multiple micro-invasive foci (< 1 mm) of tongue like projections at the nest base and slight involvement of the upper vagina and endometrial surface. The p16 immunohistochemical staining yielded negative results. The results of the HPV DNA chip test from paraffin-embedded tissue were 6 (low risk, +++) and 42 (low risk, +). The Ki-67 proliferation index was approximately 20%. The invasive foci and patient’s age were the determining differential factors for malignancy rather than benign condylomatous lesion.