title: Dual-time-point FDG-PET/CT Imaging of Temporal Bone Chondroblastoma: A Report of Two Cases.
abstract: Temporal bone chondroblastoma is an extremely rare benign bone tumor. We encountered two cases showing similar imaging findings on computed tomography (CT), magnetic resonance imaging (MRI), and dual-time-point (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)/CT. In both cases, CT images revealed temporal bone defects and sclerotic changes around the tumor. Most parts of the tumor showed low signal intensity on T2-weighted MRI images and non-uniform enhancement on gadolinium contrast-enhanced T1-weighted images. No increase in signal intensity was noted in diffusion-weighted images. Dual-time-point PET/CT showed markedly elevated (18)F-FDG uptake, which increased from the early to delayed phase. Nevertheless, immunohistochemical analysis of the resected tumor tissue revealed weak expression of glucose transporter-1 and hexokinase II in both tumors. Temporal bone tumors, showing markedly elevated (18)F-FDG uptake, which increases from the early to delayed phase on PET/CT images, may be diagnosed as malignant bone tumors. Therefore, the differential diagnosis should include chondroblastoma in combination with its characteristic findings on CT and MRI.
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Toriihara
authors.affiliation: Department of Otolaryngology, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Atsunobu
authors.initials: A
authors.lastname: Tsunoda
authors.affiliation: Department of Human Pathology, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Takemoto
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kubota
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Youichi
authors.initials: Y
authors.lastname: Machida
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Ukihide
authors.initials: U
authors.lastname: Tateishi
keywords: Dual-time-point FDG-PET/CT; MRI; Temporal bone chondroblastoma