Pitfalls in diagnostics of hip pain: osteoid osteoma and osteoblastoma.

Osteoid osteoma and osteoblastoma are benign bone tumors that occur most often in adolescents and predominantly in males. Typical clinical symptoms, such as reduced range of motion of adjacent joints, nocturnal bone pain and relief of pain using non-steroidal anti-inflammatory drug therapy especially in osteoid osteoma may lead to the correct diagnosis. However, these symptoms are not always apparent and specific. In radiographic examinations, the initial changes are often uncharacteristic causing further delay in diagnosis. Magnetic resonance imaging is increasingly used for screening, but early findings in the course of disease might not lead to the definite diagnosis. Both entities (especially osteoid osteoma) occur frequently in the area of the hip. To demonstrate pitfalls in the diagnostic pathway of hip pain caused by benign bone tumors, we present two cases with osteoid osteoma and one with osteoblastoma.