Subperiosteal Osteoid Osteoma in the Coronoid Fossa Mimicking Early Elbow Arthropathy: A Case Report.

Introduction: The elbow pain and restricted movement is a nagging problem and elbow arthropathies need to be excluded. On rare instances, uncommon etiology like a benign lesion is the culprit and the diagnosis would require judicious clinicoradiological correlation. Osteoid osteoma in the intra- or juxta-articular region is reported in the literature as rare, sporadic report. Case Report: A 23-year-old, Indian male patient presented with a provisional diagnosis of early elbow arthropathy on account of unexplained pain and restricted elbow movement without a history of trauma. He was subjected to appropriate investigations revealing synovial hypertrophy, effusion, and bone edema suggestive of early arthropathy. Additional imaging led to an uncommon definitive diagnosis. An intra-articular osteoid osteoma was found over the medial aspect of the coronoid fossa with a thin rim of cortical rim projecting anteriorly. The lesion was diagnosed and delineated on computerized tomography and an open excision of the lesion and synovectomy was done for histopathological evaluation. Histology confirmed the presence of an osteoid osteoma at an uncommon location. Conclusion: The careful appreciation of radiological images is critical to not miss significant etiology that may mimic non-specific elbow pain. High index of suspicion coupled with appropriate diagnostic imaging results in early diagnosis and appropriate management. Osteoid osteoma should be a differential diagnosis in cases with pain and restricted elbow movement and excision of which results in recovery of painless range of motion.