Intraosseous CSF Fistula in a Patient with Gorham Disease Resulting in Intracranial Hypotension

Discussion

The pathophysiology of Gorham disease, also known as “vanishing bone disease” or “massive osteolysis,” remains poorly understood. In the early stage, resorbed bone is replaced by non-neoplastic hypervascular angiomatous and fibrous connective tissue, with proliferative vessels showing either capillary, sinusoidal, or cavernous histology. In the later stages, progressive dissolution of bone occurs, with replacement by fibrous tissue.^1,9 Although the exact nature of the disease remains unknown, the effects of hyperemia, changes in local pH-stimulating hydrolytic enzyme activity, and increased osteoclast activity have all been proposed as contributing factors.¹⁰

Gorham disease occurs in men or women of any age group but is usually discovered before 40 years of age. It may involve any bone within the axial or appendicular skeleton, though spine and visceral involvement have higher morbidity and mortality.^1,3,4 Chylothorax from accumulation of lymph or thoracic duct disruption may also be associated with significant morbidity.^1,4,11 Bone destruction tends to be regional, unimpeded by joint or disk spaces, and progressive. Medical treatment options include antiosteoclastic agents (bisphosphonates), radiation therapy, and interferon α 2b.^10,11 Although resection has been attempted in localized disease, no single therapy is effective. MR imaging typically shows replacement of normal bone marrow with high T1 signal intensity from fat. In our case, very high signal intensity within lumbar vertebral bodies was also visible on T2-weighted images due to CSF accumulation from the fistula.

Cerebellar tonsillar ectopia in our patient was a manifestation of intracranial hypotension caused by a high-volume lumbar CSF fistula, with syrinx formation secondary to foramen magnum obstruction. Chiari I malformation has been described in 5 other patients with Gorham disease and in 2 with similar conditions.^5⇓⇓–8 Agrawal et al⁴ reported a duropleural fistula in a patient with Gorham disease with a Chiari I malformation, but a potential relationship was not discussed. The likely etiology of the CSF fistula in our patient is similar to that proposed in previously reported cases: dural erosion by the angioproliferative process in the adjacent bone.¹¹

In any patient with suspected Chiari I malformation, MR images should be examined before decompression for signs of intracranial hypotension, such as sagging of posterior fossa structures, inferior displacement of the third ventricle, dural venous sinus enlargement, and diffuse dural enhancement. These findings should prompt an investigation to identify the source of the CSF leak. Direct treatment of the leak is the appropriate step, rather than suboccipital decompression surgery. The cumulative treatment effects of repeat blood patching and embolization in this case were sufficient to improve imaging findings of CSF hypotension and symptoms. Percutaneous injection of autologous blood or liquid embolics such as n-BCA can be performed safely under low-radiation-dose CT guidance. Laminectomy or fusion was not attempted due to fear of spinous instability or vertebral collapse.