Utility of F-18 FDG PET/CT on the evaluation of primary bone lymphoma

Purpose: Primary bone lymphoma (PBL) is a rare type of malignant lymphoma. Few data have been reported regarding the utility of F-18 FDG PET/CT in this disease. The aim of this study was to assess the role of F-18 FDG PET/CT in the diagnosis and therapeutic effect evaluation of PBL.

Materials and methods: A total of 19 consecutive patients with PBL were enrolled. Whole-body PET/CT scan was performed for all patients. The diagnosis of PBL was established by histopathology and immunohistochemistry.

Results: F-18 FDG PET/CT was positive in 94.7% (18/19) of patients. Uptake of FDG in lesions was intense with SUVmax of 15.14 ± 11.82. Multiple involved lesions were found in 47.4% (9/19) patients, while 52.6% presented with a single involved lesion. Based on the lesions, PET detected 98.9% (87/88) lesions. Among them, 71.6% (63/88) lesions were found to be located in axial skeleton and 28.4% (25/88) in the extremity skeleton. FDG PET/CT also found the lesions infiltrate to the surrounding soft tissue in 84.2% (16/19) patients. On the syn-modality CT, the bone destruction was noted in 43.2% (38/88) of the lesions, of which 50.0% lesions presented as slight change in bone density and 50.0% as severe change. The diagnostic sensitivity of PET was much higher than that of CT (98.9% vs. 43.2%, P=0.000). PET/CT was performed for evaluation of treatment response in 13 patients. In 12 patients with complete response(CR), PET/CT found the 25 lesions were F-18 FDG fully resoluted after treatment, however, bone destruction was still presented in 72.0% (18/25) lesions.

Conclusions: The present study suggests that F-18 FDG PET/CT was a sensitive imaging modality for diagnosis and treatment response evaluation of PBL.