Ga-67 scintigraphy in acute leukemia

A 29-year-old woman had a 2-month history of increasing weakness and recurrent nose bleeding. Physical examination revealed no abnormalities except for mild splenomegaly. A blood count obtained at hospital admission revealed pancytopenia. Ga-67 imaging was performed using a large-field-of-view gamma camera and a medium-energy collimator 48 hours after the administration of 8 mCi Ga-67 citrate. The scan revealed a lack of normal Ga-67 biodistribution and generalized, diffusely increased osseous uptake of the radionuclide without focal abnormalities, consistent with the diagnosis of widespread bone marrow involvement by malignancy. Bone marrow biopsy showed massive replacement of normal cellular elements by acute lymphoblastic leukemia. This is an unusual case of altered biodistribution of Ga-67 mimicking a "normal" bone scan. This pattern should suggest the presence of an infiltrative marrow process.