18F-FDG PET/CT Findings in a Patient With Neutrophilic Leukemoid Reaction Associated With Multiple Myeloma

F-FDG PET/CT was performed on a 48-year-old woman with leukocytosis (white blood cell count 57.10 × 10/L, 84.0% neutrophils) and monoclonal gammopathy to investigate the possibility of reactive neutrophilia secondary to plasmacytoma. On the background of skeletal "superscan," the maximum intensity projection image of PET demonstrated the highest metabolic region in the left sacrum, which was confirmed as an osteolytic lesion by CT. Biopsy of the sacral lesion revealed a plasma cell myeloma, indicating the diagnosis of neutrophilic leukemoid reaction associated with multiple myeloma. The white blood cell counts dramatically dropped to the normal level after 1 cycle of chemotherapy for multiple myeloma.