Scapular Osteoid Osteoma: An Extremely Rare Case with an Atypical Clinical Presentation

Osteoid osteoma (OO) is a benign osteoblastic tumor that rarely occurs in the scapula and may present with atypical clinical and imaging findings. A 25-year-old woman presented with a 2-month history of right shoulder pain without nocturnal pain. Radiographs revealed a well-defined osteolytic lesion with internal calcification and surrounding osteosclerosis in the scapular body. Computed tomography (CT) demonstrated a 15-mm lesion containing an 11-mm coarse calcification, whereas magnetic resonance imaging showed surrounding bone marrow edema. The differential diagnosis included OO and osteomyelitis. Surgery was performed for pain relief and definitive diagnosis. Histopathological examination revealed immature woven bone trabeculae within a fibrovascular stroma, with prominent osteoblastic rimming and minimal cytologic atypia, confirming the diagnosis of OO. The patient remained asymptomatic at the 1-year follow-up, and radiographs showed no evidence of local recurrence. OO of the scapular body is extremely rare and may present without the characteristic nocturnal pain. CT is particularly useful for identifying the nidus, whereas histopathological examination remains important for definitive diagnosis.