Presentation
Hip pain. Remote history of breast cancer.
Patient Data
Single (delayed) phase whole body bone scan obtained for right hip pain shows increased radiotracer uptake about the right hip typical for osteoarthritis. Additional degenerative uptake is present in the shoulders, right hand and left ankle/foot.
An incidental focus of increased radiotracer uptake is present over the left anterior calvarium. Left lateral spot images confirms the abnormality.
X-rays obtained for incidental, indeterminate osteoblastic bone lesion in the left frontal region of the skull on whole body bone scan.
Frontal view is normal. Lateral view demonstrates an ovoid lucent lesion potentially corresponding with bone scan abnormality.
Non contrast CT head obtained to further evaluate the calvarium shows a mildly expansile, lucent lesion in the left frontal bone measuring 3.5 cm in length.
Given the appearance and desire to avoid the need for biopsy, a Tc-99m tagged RBC scan was obtained.
Planar and SPECT images obtained 3 hours after radiopharmaceutical administration show localization and retention of the radiolabeled RBCs to the left anterior skull lesion, confirming the diagnosis of a benign hemangioma.
Case Discussion
Hemangiomas are an abnormal disorganized proliferation of vascular channels with interspersed fat. Most frequently they are an incidental finding and asymptomatic. When arising in bone, they are typically found in the spine and will usually be diagnosed based upon a characteristic CT or MRI appearance. Unfortunately, they may have an atypical appearance that is difficult to differentiate from malignant lesions. In such cases, Tc-99m MDP or other bone imaging agents may be helpful if the lesion shows no abrnormal osteoblastic activity. Unfortunately, as with CT and MRI, some osseous hemangiomas will show nonspecific uptake on a bone scan, as in this instance, leading to further evaluation. While use of Tc-99m RBC blood cell scan is well recognized for the diagnosis of hepatic hemangiomas, the nuclear medicine exam also has a valuable role in identifying hemangiomas at other anatomic sites.