Abstract
Anaplastic lymphoma kinase-positive large B-cell lymphoma（ALK(+) LBCL）is rarely encountered in clinical practice. Some cases have rare plasmoblastic differentiation, extranodal bone and bone marrow involvement, low sensitivity to conventional chemotherapy, and poor prognosis. This study retrospectively analyzed the diagnosis and treatment of a patient with ALK(+) LBCL who was first misdiagnosed with multiple myeloma based on the presence of bone destruction and bone marrow involvement in Linyi Central Hospital, and the relevant literature was reviewed. The patient was a 64-year-old man who was admitted to the hospital for half a month with cough and sputum accompanied by chest and back pain. He was diagnosed with multiple myeloma and was partially relieved by three courses of VRD chemotherapy. Two months after the self-discontinuation of these medications, he experienced paraplegia. Pathological examination following the resection of an intrathoracic space-occupying lesion confirmed ALK-positive large B-cell lymphoma. The patient was treated with three cycles of ALK inhibitor combined with the CHOP regimen, followed by two additional cycles of daratumumab, which led to transient clinical remission.