title: Potential pitfall of FDG PET/CT in assessing residual masses postchemotherapy.
abstract: A 22-year-old man with primary mediastinal choriocarcinoma and bilateral lung metastases underwent an FDG PET/CT scan after completing chemotherapy. Serum beta-human chorionic gonadotropin had normalized. PET/CT showed increased FDG uptake in the anterior mediastinal and lung lesions, suspicious for residual disease. After resection of the mediastinal and lung lesions, histopathology revealed necrosis and fibrohistiocytic reaction with no viable tumor. There was discordance between beta-human chorionic gonadotropin (negative) and FDG PET/CT (positive) findings, with PET/CT findings being false positive. Awareness of this potential pitfall of FDG PET/CT is important, and caution should be exercised when using FDG PET/CT to assess residual masses after chemotherapy.
authors: Department of Diagnostic Imaging, National University Hospital, Singapore. suat_jin_lu@yahoo.com
authors: Suat-Jin
authors: SJ
authors: Lu
authors: Alvin Seng Cheong
authors: AS
authors: Wong
authors: Ju-Ee
authors: JE
authors: Seet
authors: Cheng
authors: C
authors: Hao
authors: Arvind
authors: A
authors: Sinha
mesh_terms: D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D008297:Male; D008479:Mediastinal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D064847:Multimodal Imaging; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18