Primary mantle cell lymphoma complicated with cutaneous diffuse large B-cell lymphoma, leg type: a rare case report of composite non-Hodgkin lymphoma in different organs

Background Composite lymphomas (CLs) are a kind of rare disease that two distinct categories of lymphomas occur in the same patient. Histologically, composite lymphomas can be composed of a Hodgkin’s lymphoma and a non-Hodgkin lymphoma or two distinct non-Hodgkin lymphomas. So far, most of the cases have been reported to occur in a single anatomical site or mass. Case presentation: A 61-year-old man without any B-type symptoms complained of an enlarging mass in the abdomen for one month. A 10 × 10 cm abdominal mass could be touched in the hypogastric region. Through pathological biopsy, mantle cell lymphoma can be diagnosed. After one cycle chemotherapy regimen of FCD, red rashes and blisters came out on the patient's right lower extremity. Cutaneous diffuse large B-cell lymphoma (DLBCL) was diagnosed by skin biopsy. In this report, we describe a case of composite lymphoma occurring in different organs, which consisted of primary mantle cell lymphoma (MCL) and cutaneous DLBCL, leg type. The patient then received a series of chemotherapy regimens without rituximab then achieved partial response (PR). Conclusions To our knowledge, this is a rare case of CLs occurring in different anatomic sites that were treated by chemotherapy and achieved PR. As we learn more about the mechanisms and treatment of CLs, we look forward to more treatment options in the future for patients to give them a better prognosis.