We describe 2 cases of skeletal "superscan" with F-18-choline PET/CT in prostate cancer (PCa) patients. Both cases demonstrated diffuse skeletal involvement besides their primary prostate tumor. The first impression was that this presentation would be related to diffuse tumoral skeletal invasion by PCa as often seen in Tc-99m-MDP bone scintigraphy. In both cases, the bone involvement was shown to be caused by hematological disease (polycythemia vera and chronic myelomonocytic leukemia), demonstrating the importance of also considering the presence of myeloproliferative syndromes when presented with diffuse bone disease on choline PET/CT performed in PCa patients.