Role of peripheral blood MRD and 18F-FDG PET in the post-CAR relapse setting: a case study of discordant peripheral blood and bone marrow MRD.

Background: Chimeric antigen receptor (CAR) T cell therapy is an effective salvage therapy for pediatric relapsed B-cell acute lymphoblastic leukemia (B-ALL), yet is challenged by high rates of post-CAR relapse. Literature describing specific relapse patterns and extramedullary (EM) sites of involvement in the post-CAR setting remains limited, and a clinical standard for post-CAR disease surveillance has yet to be established. We highlight the importance of integrating peripheral blood minimal residual disease (MRD) testing and radiologic imaging into surveillance strategies, to effectively characterize and capture post-CAR relapse.

Management of Differentiated Thyroid Cancer: The Standard of Care.

In the past decade, the management of differentiated thyroid cancer (DTC) underwent a paradigm shift toward the use of risk stratification with the goal of maximizing the benefit and minimizing the morbidity of radioiodine (I) therapy. I therapy is guided by information derived from surgical histopathology, molecular markers, postoperative diagnostic radioiodine scintigraphy, and thyroglobulin levels. I is used for diagnostic imaging and therapy of DTC based on physiologic sodium-iodine symporter expression in normal and neoplastic thyroid tissue.

Pediatric Esophageal Squamous Cell Carcinoma Staged With 18F-FDG PET/CT.

A 15-year-old boy with autism and swallowing dysfunction presented with a 6-month history of fatigue, intermittent abdominal pain, and weight loss. He later became febrile and had multiple episodes of coffee ground emesis and melena stools. An upper endoscopy showed an esophageal mass, and a subsequent F-FDG PET/CT scan confirmed this finding.

18F-FDG PET/CT With Diffusely High FDG Uptake Throughout Subcutaneous Adipose Tissues.

A 9-year-old girl presented with facial rash, angioedema, fevers, and night sweats. She was diagnosed with chronic active Epstein-Barr virus infection and placed on chronic steroid treatment. F-FDG PET/CT performed 3 weeks following presentation revealed diffuse subcutaneous soft tissue FDG activation throughout the entire body, with likely localization to white subcutaneous adipose tissue.