A 51 year old man with paraneoplastic cerebellar degeneration from gastric adenocarcinoma showed cerebellar hypermetabolism and increased perfusion on brain FDG‐PET scan and SPECT during the acute stage of his illness. The patient underwent subtotal gastrectomy. The intensity of the hypermetabolism had decreased markedly on follow‐up FDG‐PET 3 months later following two cycles of chemotherapy. We suggest that the cerebellar hypermetabolism may have been due to an acute inflammatory process associated with an immunological reaction.
