Primary large B‐cell lymphoma of the bone marrow

Abstract

A diagnosis of primary bone marrow lymphoma, classified as diffuse large B-cell lymphoma, was made in a 31-year-old man. He presented with persistent fever and pancytopenia and reported pain in the pelvis and femora. Computed tomography imaging showed hepatosplenomegaly but no lymphadenopathy. On magnetic resonance imaging (MRI), the right ilium and both femora demonstrated abnormal signals with low intensity on T1-weighted images and high intensity on T2-weighted images (top left). A bone marrow biopsy from the right iliac crest showed diffuse infiltration by large CD20-positive cells. Cytogenetic analysis of bone marrow cells was normal. A staging 18F-fluorodeoxyglucose positron emission tomography (PET) scan revealed striking disseminated bone marrow uptake without evidence of hepatic, splenic or lymph node involvement (top right). He underwent chemotherapy with six courses of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone), followed by high-dose chemotherapy combined with autologous peripheral blood stem cell transplantation. At the end of the treatment, the PET and MRI scans were repeated; while persistent bone marrow disease was suggested by MRI (bottom left), the PET scan was normal (bottom right). The patient remains in complete remission at 12 months. Although diffuse large B-cell lymphoma frequently involves the bone marrow, isolated bone marrow involvement is rare. PET scanning can be useful in diagnosis.