Document Type

Conference Proceeding

Publication Date

5-1-2026

Abstract

Osteoid osteoma is a benign osteogenic tumor that accounts for approximately 10% of all benign bone tumors and predominantly affects adolescents and young adults. It classically presents with nocturnal pain that responds dramatically to nonsteroidal anti-inflammatory drugs, a feature attributed to increased prostaglandin production within the nidus. The femur and tibia are most commonly involved, whereas upper extremity lesions are relatively uncommon. A 19-year-old male presented with nearly two years of chronic, progressive left lateral elbow pain and left wrist weakness. The pain was nocturnal, radiated along the left arm, and was markedly relieved by nonsteroidal antiinflammatory drugs. He was initially evaluated by orthopaedic surgery and was diagnosed with lateral epicondylitis; initial radiographs and ultrasound examinations were normal. Due to persistent nocturnal pain and worsening wrist weakness, MRI was obtained, demonstrating extensive bone marrow edema in the lateral distal humerus with a subtle subcortical lesion. Subsequent computed tomography revealed a well-circumscribed subcortical lucent lesion with a sclerotic nidus, consistent with osteoid osteoma. Diagnosis was confirmed by CT-guided biopsy. The patient underwent percutaneous cryoablation, resulting in complete resolution of pain and full restoration of function after a single treatment. To our knowledge, this is the first case to report a lateral humeral epicondyle osteoid osteoma causing posterior interosseous nerve syndrome being misdiagnosed as lateral epicondylitis. In the elbow region, osteoid osteoma has been reported to present as lateral elbow pain, stiffness, or weakness, often leading to delayed or incorrect diagnoses. Compression or irritation of the posterior interosseous nerve by osteoid osteoma of the proximal radius has been reported in the literature, while compression of the posterior interosseous nerve by osteoid osteoma of the distal humerus has never been documented before. This case illustrates how periarticular osteoid osteoma can produce symptoms that reflect secondary neural involvement rather than primary joint or tendon pathology. In this patient, progressive wrist extensor weakness without sensory disturbance was consistent with posterior interosseous nerve dysfunction. Given the close anatomical relationship between the posterior interosseous nerve and the lateral elbow, local inflammatory changes and reactive bone marrow edema surrounding the lesion likely contributed to nerve irritation or compression, resulting in isolated motor deficits. This mechanism explains the discordance between prominent neurological symptoms and the absence of intrinsic nerve pathology, proven by complete symptom resolution post-cryoablation. This case highlights the diagnostic challenge of periarticular osteoid osteoma and emphasizes the importance of considering this diagnosis in young patients who present with chronic nocturnal elbow pain and wrist weakness despite non-diagnostic initial imaging.

Comments

American College of Physicians Michigan Chapter and Society of Hospital Medicine Michigan Chapter 2026 Resident and Medical Student Day, May 1, 2026, Troy, MI

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