Primary retroperitoneal diffuse large B-cell lymphoma presenting with numb chin syndrome and painful ophthalmoplegia.

Numb chin syndrome (NCS) and painful ophthalmoplegia (PO) are neurological syndromes associated with the disturbance of certain cranial nerves and their downstream nerves. These syndromes are caused by various diseases, and, in rare cases precede the diagnosis of systemic malignant lymphoma. We herein present the case of a 59-year-old man diagnosed simultaneously with NCS and PO caused by a tumor located around the cavernous sinus and with diffuse large B-cell lymphoma that was identified via biopsy of a large retroperitoneal tumor. He was successfully treated with a standard rituximab-containing chemotherapy combined with high-dose intravenous methotrexate and intrathecal chemotherapy.