Discussion

Shoulder pain and limited range of motion are common general complaints, often related to trauma, arthritis, and subacromial impingement. Patients presenting with similar symptoms secondary to massive osteolysis are much rarer; to our knowledge, only a few have been reported in the literature. The clinical presentation of this case, along with normal inflammatory laboratory values and lack of leukocytosis, was not consistent with an infectious process or other inflammatory causes. The patient did not have diabetes mellitus.

Gorham-Stout disease, commonly known as “vanishing bone disease,” is a rare vascular disorder characterized by progressive osteolysis. It is a multisystem, developmental disorder of lymphangiogenesis that also affects bone, with slow endothelial cell turnover and associated cutaneous lymphatic malformations. Gorham-Stout, which predominately affects males, is typically diagnosed based on imaging findings and biopsy. The mean age of presentation is 12.8 years. It is polyostotic, typically involving the ribs, cranium, clavicles, and cervical vertebrae.¹ A treatment approach involving oral medications to suppress the immune system, and medications such as interferon alpha-2b, and rapamycin to target lymphatic vessel formation, has been found to inhibit disease progression, symptoms, and complications. Surgical intervention may be necessary to stabilize or remove affected bones as well as treat symptoms of the disease.¹

In this case, the subsequent diagnosis of a Chiari I deformity and large syrinx clinched the diagnosis of neuropathic joint with massive osteolysis. The presentation of a neuropathic joint may include severe and rapid joint destruction, effusion, limited range of motion, and instability. Typically, the joints are painless and lack significant neurological deficits.

Physical examination may demonstrate abnormalities in proprioception and decreased or blunted deep-pain sensation.^{2 - 4} Imaging findings include generally normal bone density, large joint effusion, and severe, massive, bony destruction without new bone formation. Cross-sectional imaging supports the diagnosis and assessment of the extent as well as underlying causes. Common etiologies for neuropathic joints include diabetes mellitus, syrinogomyelia, tabes dorsalis, alcoholism, and spinal cord injury.²

According to the literature, when the shoulder is involved, it is typically secondary to syringomyelia and Chiari I deformity.^{3, 5} The exact etiology of osteolysis is unclear but may be related to alteration in blood flow, leading to osseous hyperemia and increased bone resorption.³ MRI of the entire spinal cord is the preferred modality to assess the size and extent of the syrinx. The craniocervical junction should be evaluated for caudal descent of the cerebellar tonsils greater than 5 mm below the foramen magnum and narrowing of the cerebrospinal fluid spaces to indicate Chiari I deformity. In our case, the diagnosis was supported by the MRI findings ( Figure 3 ).⁶

Treatment of the affected joint can vary from conservative management to steroid injections, proper joint splinting, and physical therapy. Other treatment options include arthrodesis and joint reconstruction.⁷ Treatment of the underlying etiology is important.