Altered FDG Biodistribution in Subcutaneous White Fat on PET/CT Following l-Asparaginase Chemotherapy

Abstract

A 13-year-old boy with mediastinal T-cell lymphoblastic lymphoma demonstrated an altered biodistribution with diffuse activity in subcutaneous white adipose tissue and decreased visceral activity on interim posttreatment FDG PET/CT. This altered biodistribution was attributed to administration of the chemotherapeutic enzyme l-asparaginase 3 hours preceding the PET/CT, altering adipocytes amino acid and glucose metabolism. Treatment response assessment was adversely affected by the altered biodistribution, emphasizing the importance of maximizing the time between chemotherapy and PET/CT during successive oncologic treatment cycles. Because adipocytes protect leukemic cells in culture from l-asparaginase, we hypothesize that white adipose tissue–altered biodistribution may be related to l-asparaginase resistance.

Diffuse White Adipose Tissue 18F-FDG Uptake—An Unusual Finding on 18F-FDG PET/CT

“…Wong et al 7 reported these findings in a case of lymphoblastic lymphoma treated with chemotherapy containing corticosteroids. Recently published study by Young et al 8 reported these findings in a patient with T-cell lymphocytic lymphoma treated with high-dose l -asparaginase chemotherapy 3 hours before the scan. Previous reports have suggested that herbal medicines, 2,9 such as the one taken by our patient for her herpes infection, could contain corticosteroids, resulting in enhanced WAT uptake of 18 F-FDG.…”

Chimeric Antigen Receptor T-Cell Therapy of Neurolymphomatosis Monitored by FDG PET/CT

“…At present, CAR-T has improved outcomes in relapsed/refractory hematological malignancies, including B-acute lymphoblastic leukemia and large B-cell lymphoma. 9 18 F-FDG PET/CT has been used in the diagnosis and therapy response evaluation of LBL, [10][11][12] neurolymphomatosis, 13,14 and monitoring CAR-T. 15,16 The present case emphasized the value of 18 F-FDG PET/CT in evaluating the therapy response of neurolymphomatosis after CAR-T therapy.…”

FDG altered biodistribution in white adipose tissue, a rare entity: case report and review of the literature

“…The phenomenon of diffuse FDG activity by white fat following corticosteroid treatment is an uncommon finding, predominantly observed in young cancer patients, with only about 20 pediatric leukemia and lymphoma cases with this phenomenon documented in a few early observational studies and case reports within the medical literature (Table 1 ) (Wong et al 2020 ; Young et al 2021 ; Kapoor et al 2021 ; Sharp et al 2012 ). Induction chemotherapy regimens for leukemia and lymphoma frequently incorporate corticosteroids such as prednisone or dexamethasone to be administered alongside agents such as vincristine.…”

“…Areas of active disease were obscured by white fat activity, and repeat imaging one week later resulted in relatively normalized biodistribution sufficient to detect previously hidden lesions Staack, Mayo Clinic, Arizona, USA (2020) (Staack et al 2020 ) 1 (1) 59-year-old woman with lymphoma In addition to chemotherapy, her treatment regimen also included dexamethasone to prevent cerebral edema. Therefore, altered FDG biodistribution was ascribed to glucocorticoid-induced Cushing syndrome Young, Yale New Haven Hospital, USA (2021) (Young et al 2021 ) 1 (0) 13-year-old boy with T-cell lymphoblastic lymphoma Although the patient received high dose corticosteroids with induction chemotherapy, the authors hypothesized that L-asparaginase, which was administered only three hours prior to FDG-PET/CT, may have been responsible for diffuse white adipose uptake Kapoor, University of Kentucky Chandler Medical Center, USA (2021) (Kapoor et al 2021 ) 1 (0) 7-year-old boy with T-cell lymphoblastic lymphoma Iatrogenic Cushing syndrome resulting from dexamethasone included in induction chemotherapy was favored as the cause of FDG localization to white fat Bansal, All India Institute of Medical Sciences, India (2021) (Bansal et al 2021 ) 1 (1) 38-year-old woman with cervical cancer While the patient was treated with chemoradiation, altered FDG biodistribution was found to be potentially caused by an herbal medication for herpes zoster which could contain corticosteroids Singhal, All India Institute of Medical Sciences, India (2023) (Singhal et al 2023 ) 1 (1) 12-year-old girl with lymphoma Imaging with FDG-PET/CT was performed for end-of-treatment evaluation after four cycles of chemotherapy. Incidentally, the patient had been receiving prednisolone for nephrotic syndrome for two weeks prior to imaging, resulting in diffuse white fat activity Although most commonly described in pediatric patients having recently undergone induction chemotherapy, this rare pattern of FDG uptake has been described in other patient populations as well …”