Bilateral bone marrow edema syndrome of the humeral head mimicking avascular necrosis: a case report

Background: Bone marrow edema syndrome (BMES), previously referred to as transient osteoporosis, is an uncommon and underdiagnosed self-limiting condition typically affecting the weight-bearing joints of the hip and lower limb. Its occurrence in upper limb or non-weight bearing joints is particularly rare. Case presentation: We report the case of an otherwise healthy 42-year-old man who gradually developed severe and disabling left shoulder pain over the course of 6 months. Nine months after onset, he presented clinically with bilateral involvement and radiologically (magnetic resonance imaging, MRI) with diffuse BME associated with a subchondral insufficiency fracture, suggestive of proximal humeral avascular necrosis. Clinical evidence of subacromial shoulder impingement and MRI findings of bilateral subchondral bursitis and tenosynovitis with effusion of the biceps tendons likely resulted from primary BME, as musculoskeletal sonography confirmed the absence of rotator cuff tears. Repeated MRI findings at 2, 12, and 18 months documented near complete resolution of both edema and fracture, consistent with BMES of the proximal humerus. During this time, the patient reported a gradual improvement in both pain symptoms and range of motion. The clinical picture of insidious shoulder pain, exacerbated by activity and improved by load relief, in the absence of predisposing factors for osteonecrosis or antecedent trauma in patients of middle age, should indicate the possibility of the diagnosis of BMES. Conclusions: This unprecedented report documents a rare case of bilateral BMES of the humeral head mimicking avascular necrosis. The correct diagnosis of BMES within an atypical anatomical location avoids invasive measures in the affected bone. The misdiagnosis of secondary BME and idiopathic osteonecrosis can be avoided by recognizing the characteristics of BME and subchondral fractures of the humeral head in the absence of rotator cuff tears, as well as their evolution on serial MRI.