A case of large cell neuroendocrine carcinoma of the uterine cervix misdiagnosed as adenocarcinoma in Thinprep cytology test.

Large cell neuroendocrine carcinoma (LCNEC) of uterine cervix is a rare malignancy with aggressive behavior and poor clinical outcome even in its early stage. Few cytopathologic features of cervical LCNEC have been reported previously. A 57-year-old postmenopausal African American female, presented to the local health department with a chief complaint of heavy vaginal bleeding. A 45-year-old female presented with 20 months of vaginal pruritus and foul odor. Cervical malignancy was suspected by pelvis magnetic resonance imaging. Thinprep cytology test demonstrated ball-like tumor cell clusters in a necrotic background. Cytologic diagnosis of adenocarcinoma was rendered. However, the histologic and immunohistochemical examination of cervical biopsy revealed the LCNEC of the uterine cervix. Due to its rarity, LCNEC may pose a diagnostic challenge in cervical cytology. Cytopathologists should pay attention to the cytological features of cervical LCNEC, such as rosettoid pattern, nuclear molding, and thin nuclear membrane for differentiation from other mimics.