Case Report
Taishi Okada, Hiroyuki Futa
Abstract
Chondromyxoid fibroma is an extremely rare, benign cartilaginous tumor, which might be misdiagnosed as hondrosarcoma. Recent studies reported that PET/CT could distinguish benign cartilaginous tumors from chondrosarcomas with maximum Standardized Uptake Value (SUVmax) of more than 2.0. In the literature, 4 cases of chondromyxoid fibroma have been reported on PET/CT with high accumulation of 18FFDG. However, no paper has explained the reason for this high accumulation. In this paper, we present a case of femoral chondromyxoid fibroma and discuss the rational reason for high accumulation of 18F-FDG by PET/CT in accordance with histology. Here, a 20-year-old female presented with a lesion located in the medial aspect of the left distal femur. Radiography revealed an eccentric radiolucency in the metaphysis of the left distal femur. CT images clearly demonstrated a cortical destruction of the posterior wall. PET/CT images clearly demonstrated an abnormal 18F-FDG uptake of the distal aspect of the left femur with SUVmax value of 6.6, indicating a chondrosarcoma. In the present case, histology showed a number of multinucleated giant cells at the periphery of the lobules in the tumor, which can explain the high accumulation.