Osteoblastoma of the patella: case report.

A 34-year-old man came to our clinic because of left knee pain and mild swelling. Local tenderness over the peripatellar area was observed during physical examination. The range of motion of the knee was full. The radiographic presentation of the patella revealed an osteolytic lesion with a thin sclerotic rim without evidence of extra-articular involvement. The computed tomography revealed an upper pole intraosseous lesion. Intralesional curettage and allogeneic bone grafting were carried out. The pathologic examination demonstrated primitive osteoblasts, with osteoid features and many giant cells. A diagnosis of the osteoblastoma was made. Following surgery, the patient regained full range of motion and was pain-free. Complete healing of the lesion without evidence of recurrence was noted in follow-up radiographs 2 years postoperatively.