[Case of concurrent second branchial cleft cyst and diffuse large B-cell lymphoma].

Second branchial cleft cyst and lymphoma are two common types of neck masses. The etiology, clinical manifestations, imaging findings, treatment options, and prognosis of these two entities differ. Clinically, the occurrence of both lesions at the same anatomical site is rare. Herein, we report a case of concurrent second branchial cleft cyst and diffuse large B-cell lymphoma in the same anatomical region. The final diagnosis was confirmed by clinical features, ima-ging findings, and ultrasound-guided biopsy. The patient received the R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy regimen combined with surgical resection and finally achieved patholo-gical complete response with a favorable prognosis. This case report aims to provide a reference for the diagnosis and treatment of similar cases.