Incidental Finding of Acute Lymphocytic Leukemia in a Prostate-Specific Membrane Antigen PET/CT.

PSMA PET/CT is known to show uptake in various benign and malignant processes. The following PSMA PET/CT was performed for prostate carcinoma staging (Gleason 3 + 4 left apex; PSA 5.8). It shows incidental diffuse PSMA marrow uptake, not typical for prostate metastatic disease. No treatment had been commenced at the time of the scan. Serology and bone marrow biopsy showed B-cell acute lymphocytic leukemia. Focal PSMA uptake in the right ischium was correlated with a T1 hypointense lesion on a previous MRI and was convincing for a skeletal metastasis. Alternative diagnoses in diffuse skeletal PSMA uptake need therefore to be considered.