Usefulness of positron emission tomography-CT for diagnosis of primary bone marrow lymphoma in children.

Primary bone marrow lymphoma (PBML) is hard to diagnose in children, due to the difficult identification of malignant cells in bone marrow. The first case, a 5-year-old boy, showed knee swelling with an intermittent fever. The second case, a 12-year-old girl, showed fever of unknown origin without lymphadenopathy or hepatosplenomegaly. In both cases, the diagnosis was not confirmed despite the repeated bone marrow aspirations. Finally, bone marrow aspiration and biopsy at the positive site by positron emission tomography (PET)-CT contributed to definitive diagnosis of PBML. The PET-CT is useful for the accurate diagnosis of PBML in children with non-specific symptoms.