DOI: https://doi.org/10.36347/sasjs.2026.v12i10.004

Pages: 830-834

Background: Osteoid osteoma is a benign bone-forming tumor accounting for approximately 10–12% of all benign bone tumors. While it most commonly affects the long bones of the lower extremity, localization at the distal ulna is exceedingly rare, representing less than 1% of reported cases. Atypical locations frequently cause significant diagnostic delays due to unusual clinical and imaging presentations. Case presentation: We report a 40-year-old female patient with an 11-month history of chronic wrist pain without prior trauma. Radiographs revealed subtle osteosclerosis at the distal ulna. Computed tomography (CT) demonstrated a hypodense nodular lesion with a peripheral osteosclerotic reaction consistent with osteoid osteoma. Complete surgical excision was performed, and histopathological examination confirmed the diagnosis. The patient achieved complete pain resolution and full functional recovery at three months postoperatively. Conclusions: Osteoid osteoma of the distal ulna is a diagnostic pitfall due to its rarity. CT scan in thin sections remains the most specific imaging modality, and MRI provides complementary information regarding perilesional edema. Complete surgical excision is curative. This case underscores the importance of including osteoid osteoma in the differential diagnosis of unexplained chronic wrist pain in young patients.