Osteoid Osteoma of the Scapular Neck: A Cause of Long-lasting Unexplained Pain.

Introduction: Osteoid osteoma (OO) is a common tumor of the diaphysis of long bone, where the reported incidence is up 10% of all benign bone tumors. Its presence in flat bone is seldom mentioned in literature and can be misleading when the bone involved is in proximity to a zone of wide variety of possible pathology. We report a case of a young patient with OO in a very rare location of the body -the scapular neck - that was misdiagnosed for a long period of time before receiving adequate therapy.

Case Report: A 20-year-old female patient presented to the clinic with chronic left shoulder pain. During the past 2 years, she received medical and physical therapy, to deal with different diagnosis such as cervical spine pathology, muscular spasm, and rotator cuff disease. However, she did not improve. At time of presentation to our clinic, radiographs of the shoulder were done and turned to be inconclusively normal. After negative magnetic resonance imaging of the cervical spine, a computed tomography scan of the shoulder was done and showed a round well-defined lesion localized in the scapular neck with a focal lucent nidus within surrounding sclerotic reactive bone measuring 8.5 mm in largest diameter, compatible with OO. Bone scan showed increased uptake. The patient was given aspirin in an intention to test and treat. The patient had dramatic pain relieve at first, which confirmed the diagnosis of OO. But then, pain became unremitting, so a decision was made for radiofrequency ablation of the lesion which gave excellent results.

Conclusion: OO is a common benign neoplasm with high variable clinical picture and anatomic localization. Despite being more common in long bone, flat bone OO localization should be always kept in mind. Careful history and physical examination should be done for each patient presenting with unexplained pain; night pain should always raise suspicion of this condition. Radiographs are not always conclusive, and the patient with high suspicion of this condition should undergo more investigation to make the diagnosis.