Osteopetrosis is a heterogeneous group of rare, inherited disorders of the skeleton that results in
neurological manifestations due to restriction of growth of cranial foramina and calvarial thickening. A 25-year-old woman with a history of autosomal dominant
osteopetrosis presented to the authors' institution with
headache worsened by exertion and radiating from the occipital region forward with episodes of
choking/coughing when eating and a loss of gag reflex on physical examination. On MR imaging, she was found to have severe posterior fossa calvarial thickening resulting in a small posterior fossa and tonsillar ectopia of 9 mm and compression and deformation of the brainstem. She underwent posterior fossa
craniectomy, foramen magnum
decompression, and partial C-1
laminectomy with external durotomy. The patient did well postoperatively with resolution of symptoms. This case describes a new
neurological manifestation of autosomal dominant
osteopetrosis. To the authors' knowledge, this report represents the first described case of extreme posterior fossa calvarial thickening from autosomal dominant
osteopetrosis with associated Chiari I malformation (CM-I) requiring posterior fossa
decompression and extradural
decompression. Given previously published MR imaging data that demonstrate the association of
osteopetrosis and CM may be more common than in this case alone, the authors discuss the need for further investigation of the incidence of CM-I in patients with autosomal dominant
osteopetrosis. Additionally, they review
osteopetrosis and other diagnoses of
calvarial hyperostosis presenting as CM-I.