Diagnostic and management roles of FDG PET/CT imaging in post‐transplant lympho‐proliferation in pediatric heart transplantation.

Background: Post‐transplant lymphoproliferative disorder (PTLD) is a serious complication of pediatric heart transplant (PHTx). 18F‐FDG PET/CT has been used to differentiate early lympho‐proliferation from more advanced PTLD. We report our experience with PET/CT in the management of PTLD following PHTx. Methods: This was a retrospective study of 100 consecutive PHTx recipients at our institution between 2004 and 2018. Patients who underwent PET/CT or conventional CT scans to evaluate for PTLD or high Epstein‐Barr viral load were included. Results: Males, eight females. Median age at transplant was 3.5 months (IQR = 1.5‐27.5). Median age at PTLD diagnosis was 13.3 years (IQR = 9.2‐16.1). Median time between transplant and PTLD diagnosis was 9.5 (IQR = 4.5‐15) years. Induction agents were used in 12 patients (50%): Thymoglobulin (N = 9), anti‐IL2 (N = 2), and Rituximab (N = 1). Eighteen patients (75%) had PET/CT, of whom 14 had 18FDG‐avid PTLD. Six had conventional CT. Nineteen patients (79.2%) had diagnostic biopsy confirmation of PTLD, and 5 (20.8%) had excisional biopsies. Two patients had Hodgkin's lymphoma; nine had monomorphic PTLD; eight had polymorphic PTLD; five were classified as other. Nine patients had monomorphic PTLD, including seven with diffuse large cell lymphoma (DLBC) and one with T cell lymphoma. The majority (16/24) had multi‐site involvement at PTLD diagnosis, and PET/CT showed that 31.3% (5/16) had easily accessible subcutaneous nodes. Seventeen patients (overall survival 71%) underwent successful treatment without recurrence of PTLD. Of seven deaths (7/24, 29%), five had DLBC lymphoma, one had polymorphic PTLD and one had T‐cell lymphoma. Conclusion: PET‐CT allowed simultaneous anatomical and functional assessment of PTLD lesions, while guiding biopsy. In patients with multiple lesions, PET/CT revealed the most prominent and active lesions, improving diagnostic accuracy. [ABSTRACT FROM AUTHOR]