Intense Ga-68-FAPI Uptake in a Patient With Myositis Ossificans Mimicking Bone Malignancy

A 72-year-old man presented with right hip pain, difficulty in walking, and a mass in his right hip for 3 months. CT suggested osteonecrosis of the right femoral head and a mass in the right hip with calcification. A malignancy was suspected, and the patient was subsequently enrolled in the clinical trial of 68Ga-FAPI. 68Ga-FAPI PET/CT showed a mass in his right hip with intense FAPI activity. It was also highly suggestive of malignancy. The pathological examination after right-hip surgery confirmed the diagnosis of myositis ossificans.