Hemangioma in the patella - A case report

Hemangioma in the patella is rare, and the osteolytic finding mimics a solid tumor. In the current report, a 69-year-old male with hemangioma in the patella had pain in the anterior left knee when kneeling. The osteolysis was not obvious on plain radiographs in the anteroposterior or lateral views, but was clear in the axial view, as well as with computed tomography. Bone scintigraphy showed uptake of technetium. Magnetic resonance imaging suggested a cystic lesion, but a primary solid tumor with cystic changes could not be ruled out. After confirmation of the diagnosis by biopsy, curettage and beta-tricalcium phosphate grafting was performed. Preoperative symptoms disappeared 6 months after the operation. It is easy to miss these lesions on plain radiographs. Even after identification of the lesion, a solid tumor with a destructive nature would have been suspected because of the uptake on bone scintigraphy. In a previous report, patellectomy was performed, but curettage may be sufficient for a benign tumor, as in the current case.