¹⁸F-FDG PET/CT in the management of patients with post-transplant lymphoproliferative disorder

Objectives: Post-transplant lymphoproliferative disorder (PTLD) is a rare but serious complication in transplant patients. Although fluorine-18 2-fluoro-2-deoxyglucose PET and computed tomography (¹⁸F-FDG PET/CT) has been used for the evaluation and management of patients with PTLD, its utility has yet to be documented. We were therefore prompted to review our experience with ¹⁸F-FDG PET/CT in PTLD. Materials and methods: We retrospectively reviewed the records of consecutive patients who had undergone ¹⁸F-FDG PET/CT for evaluation of PTLD from January 2004 to June 2012 at our institution. ¹⁸F-FDG PET/CT scans were compared with other imaging modalities performed concurrently. A chart review of pertinent clinical information was also conducted. Results: A total of 30 patients were identified (14 female and 16 male; 1.7-76.7 years of age, average: 23.8 years). Twenty-seven participants had biopsy-proven PTLD and another three had been treated for PTLD because of high clinical suspicion of disease and positive ¹⁸F-FDG PET/CT findings in the absence of histological diagnosis. Eighty-three percent of these PTLD patients had extranodal involvement. In 57% of the cases, ¹⁸F-FDG PET/CT detected occult lesions not identified on other imaging modalities or suggested PTLD in equivocal lesions. The more aggressive PTLD histological subtypes demonstrated higher SUV_max compared with the less aggressive subtypes. Conclusion: ¹⁸F-FDG PET/CT is beneficial in the diagnostic evaluation of patients with PTLD. ¹⁸F-FDG PET/CT has the ability to detect occult lesions not identified on other imaging modalities, particularly extranodal lesions. In addition, ¹⁸F-FDG PET/CT may predict the PTLD subtype, as the lesions with higher pathologic grade presented with significantly higher SUV _max compared with the less aggressive forms.