HPV18-positive Small Cell Neuroendocrine Carcinoma of the Uterine Cervix Treated With Immunotherapy: A Case Report

Background: Small cell neuroendocrine carcinoma of the cervix (SCNEC) has an extremely poor prognosis. We report a case of recurrent SCNEC with CD274 [Programmed Death-Ligand 1 (PD-L1)] gene amplification and HPV18 positivity, which showed a favorable response to the immune checkpoint inhibitor (ICI) nivolumab. Case Report: A 42-year-old woman presented with a lower abdominal mass and was referred to our department. Imaging revealed a uterine cervical tumor with multiple enlarged pelvic lymph nodes. Biopsy confirmed HPV18-positive SCNEC. After one cycle of neoadjuvant chemotherapy, surgery was performed, revealing stage IIIC2p (ypT1b1, ypN1, M0) SCNEC with regional lymph-node invasion, followed by adjuvant chemotherapy. Two months later, enlargement of the para-aortic and left pelvic lymph nodes was detected. Concurrent chemoradiotherapy (CCRT) was administered, resulting in a reduction of lymphadenopathy. Seven months later, an enlarged right supraclavicular lymph node was detected. Nivolumab therapy was initiated because CD274 (PD-L1) gene amplification was detected in tumor tissue. The lymph node decreased in size, and no signs of relapse had been observed for more than three years. Conclusion: Comprehensive multimodal therapy, including standard surgery, neoadjuvant and adjuvant chemotherapy, chemoradiation for recurrent lymph nodes, and immune checkpoint inhibition, can achieve a remarkable response in advanced SCNEC harboring CD274 (PD-L1) amplification and HPV18 infection.