Dual-time-point FDG-PET/CT Imaging of Temporal Bone Chondroblastoma: A Report of Two Cases

Document Type : Case report


1 Department of Diagnostic Radiology and Nuclear Medicine, Tokyo Medical and Dental University, Yushima, Bunkyoku, Tokyo, Japan

2 Department of Otolaryngology, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan

3 Department of Human Pathology, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan


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 18F-fluorodeoxyglucose (18F-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 18F-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 18F-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.


Main Subjects

1. Dahlin DC, Ivins JC. Benign chondroblastoma. A study of 125 cases. Cancer. 1972;30:401-13.
2. Reid LB, Wong DS, Lyons B. Chondroblastoma of the  temporal bone: a case series, review, and suggested management strategy. Skull Base Rep. 2011;1:71-82.
3. Hatano M, De Donato G, Falcioni M, Sanna M. Chondroblastoma of the temporal bone. Acta Otolaryngol. 2011;131:890-5.
4. Bian LG, Sun QF, Zhao WG, Shen JK, Tirakotai W, Bertalanffy H. Temporal bone chondroblastoma: a review. Neuropathology. 2005;25:159-64.
5. de Silva MV, Reid R. Chondroblastoma: varied histologic appearance, potential diagnostic pitfalls, and clinicopathologic features associated with local recurrence. Ann Diagn Pathol. 2003;7:205-13.
6. Aoki J, Watanabe H, Shinozaki T, Takagishi K, Ishijima H, Oya N, et al. FDG PET of primary benign and malignant bone tumors: standardized uptake value in 52 lesions. Radiology. 2001;219:774-7.
7. Hamada K, Ueda T, Tomita Y, Higuchi I, Inoue A, Tamai N, et al. False positive 18F-FDG PET in an ischial chondroblastoma; an analysis of glucose transporter 1 and kexokinase II expression. Skeletal Radiol. 2006;35:306-10.
8. Tian R, Su M, Tian Y, Li F, Li L, Kuang A, et al. Dual-time point PET/CT with F-18 FDG for the differentiation of malignant and benign bone lesions. Skeletal Radiol. 2009;38:451-8.
9. Iizuka T, Furukawa M, Ishii H, Kasai M, Hayashi C, Arai H, et al. Giant cell tumor of the temporal bone with direct invasion into the middle ear and skull base: a case report. Case Report Otolaryngol. 2012; 2012: 690148.
10. Ma Y, Liu L, Huang D, Han D, Wang J, Wu W, et al. Diagnosis and treatment of giant cell granuloma of the temporal bone: report of eight cases. Acta Otolaryngol. 2012;132:657-62.