Utility of ¹⁸F-FDG PET/CT in primary non-Hodgkin lymphoma of bone

Abstract

This is a case of primary non-Hodgkin lymphoma of bone, evaluated using ¹⁸F-FDG PET/CT (PET/CT). A 16-year-old male presented with right knee pain for eight months. PET-CT showed abnormal FDG uptake at the distal right femur, throughout the right tibia, and at the left middle skull base. The patient was diagnosed as having stage III B-cell lymphoblastic lymphoma. He received chemotherapy on the basis of the NHL-BFM95 protocol. After consolidation therapy, PET/CT showed no abnormal uptake in the tibia and the skull base. The remaining uptake levels at the distal femur, the biopsy site, gradually decreased. The patient has been in complete remission for eight months after the completion of chemotherapy. PET/CT is useful for staging, and seems more useful than MRI or CT for evaluating treatment response in primary bone lymphoma. However, it is necessary to confirm the effective timing and the frequency of evaluation, taking radiation exposure and false-positive findings into consideration.