A promising treatment option for refractory male primary choriocarcinoma: report of two cases.

Male primary choriocarcinoma is a rare and invasive malignant neoplasm for which traditional chemotherapy has limited efficacy. Pembrolizumab is a humanized monoclonal anti-programmed death-1 antibody that has antitumor activity in numerous malignancies. The diagnosis and treatment of two cases of advanced male primary choriocarcinoma were retrospectively analyzed and relevant literature was reviewed to discuss the prognosis and the efficacy of different treatments, including pembrolizumab. The first patient, who presented with cough and hemoptysis, was diagnosed with primary mediastinal choriocarcinoma. He initially responded to the first-line chemotherapy of etoposide, methotrexate, actinomycin D, cyclophosphamide and vincristine, but eventually developed brain metastases. The patient did not respond to the second-line chemotherapy comprising paclitaxel and cisplatin, and he died 6.5 months after diagnosis. The second patient experienced repeated episodes of abdominal pain and was diagnosed with primary neck choriocarcinoma. He received chemotherapy regimens similar to those of the first patient. However, imaging showed no significant changes and his clinical symptoms were not improved. Immunohistochemistry showed that the expression of programmed death ligand 1 on the tumor cells was 40%, and he was administered pembrolizumab combined with chemotherapy. He achieved complete response and was subsequently switched to pembrolizumab maintenance monotherapy. He is still alive without evidence of disease 36 months after diagnosis. To our knowledge, this is the first case of advanced male primary choriocarcinoma successfully treated with pembrolizumab combined with chemotherapy. Advanced male primary choriocarcinoma is highly aggressive and insensitive to chemotherapy. Pembrolizumab may provide a promising treatment option to improve patient outcomes.