Osteoid osteoma of the proximal humerus: A misleading case

CASE REPORT A 22-year-old man was hit in the right shoulder in a traffic accident. He felt right shoulder pain 6 months after the accident and visited a physician for a careful checkup, but no definite diagnosis was established. The patient complained of continuous pain at night and underwent a diagnostic arthroscopy. No intra-articular pathology was seen. He was referred to our hospital because of persistent shoulder pain. On the patient’s initial visit to our hospital, he complained of pain around the right shoulder. The pain was worse at night and improved with anti-inflammatory medication. The range of motion was not restricted. No swelling, tenderness, or local heat around the shoulder was noted. Blood examination showed normal inflammatory markers. The remainder of the clinical examination was unremarkable. Plain radiographs taken 12 months earlier showed no tumor lesion (Figure 1). Plain radiographs at this time showed a radiolucent area surrounded by a sclerotic band (nidus) at the greater tuberosity (Figure 2). Fat suppression T2-weighted magnetic resonance (MR) arthrograms disclosed a small, rounded, highintensity area surrounded by a low-intensity ring at the same site (Figure 3). Computed tomography (CT) scan confirmed a small calcification surrounded by low-attenuation area (Figure 4). The tumor was curetted with a fine needle under fluoroscopic guidance. Histologic examination showed an interlacing network of osteoid trabeculae, consistent with an osteoid osteoma. Three years after the operation, the pa-