Case Report Discussion Aneurysmal Bone Cyst in Bone Scintigraphy: A Case Report Ya-Cing Hsu, Ya-Chin Tsai, Dom-Gene Tu, Yu-Ling Hsu Department of Nuclear Medicine, Ditmanson Medical Foundation Chia-Yi Christian Hospital Case Report A 16-year-old girl was referred for bone survey in our department. She felt bone pain at right arm for 2 weeks without swelling and trauma history. X-ray showed osteolytic lesions over right humerus. Bone scintigraphy was performed 3 hours after 20mCi 99mTc-MDP injection, revealing no definite abnormal bone uptake. Following MRI demonstrated long segmental bone marrow lesion involving metaphysis and diaphysis. Curettage and biopsy were performed, and the pathologic report revealed aneurysmal bone cyst. Later, she received further curettage and bone grafting, and kept follow up in our orthopedic OPD. Discussion Aneurysmal bone cysts usually occur in the metaphysis of the long bones in the first two decades of life. They consist of cavernous blood-filled spaces. It has been reported that there is increased uptake in a ring-like pattern around the periphery of aneurysmal bone cyst in bone scintigraphy. However, the bone scintigraphy of our case showed no definite abnormal uptake. Bone scintigraphy is not specific for aneurysmal bone cyst, but the appearance of it might reflect the pathophysiologic change. Conventional treatment for aneurysmal bone cyst has been directed at the surgical removal of the entire lesion, or as much as possible. If no coexisting lesion is identified, lesions are usually treated with curettage and bone grafting, with more aggressive treatment reserved for recurrent lesions. (A) (B) (C) (D) (E) (F) X-ray images (figure A and B) showed lytic lesions, suspicious fibrous dysplasis at right humerus. 99mTc-MDP bone images (figure C and D) had no obvious finding. MRI images (figure E and F) revealed intermediate signal on T1w and hyeprintense signal on FS T2w. X-ray images (figure G and H) showed well recovered after surgery treatments. (G) (H)