A 67-year-old man with thoracolumbar scoliosis, poor mobility, and history of frequent falls presented to the emergency department with 2 months of left shoulder pain, stiffness and reduced range of motion, and numbness and paresthesias in his left upper extremity. Ten years prior to presentation, he underwent surgical decompression for syringomyelia. A magnetic resonance imaging (MRI) scan of his cervical and thoracic spine performed 2 years prior to presentation revealed a recurrent syrinx extending from C1 to T11, which was not resected because it did not cause symptoms at that time. On physical examination, he had mild tenderness to palpation and reduced range of motion of the left shoulder with abduction and flexion limited to 120° (normal range of motion, 180°). The left scapular muscles were atrophic, and pain and temperature sensation were reduced in his proximal left arm, and dorsal aspect of his left shoulder. His complete blood cell count, serum glucose levels, C-reactive protein levels, and erythrocyte sedimentation rate were normal. Results of tests for rheumatoid factor and antinuclear antibody were negative. Left shoulder radiograph showed complete absence of the left humeral head and a well-demarcated smooth osseous margin of the proximal humerus with associated soft tissue swelling and periarticular calcification (Figure 1). A chest radiograph taken 2 years prior revealed a normal left shoulder joint. The patient was hospitalized for further evaluation and treatment.