Diffuse Calvarial Hyperstosis.

Calvarial hyperstosis can be an idiopathic benign finding or secondary to a metabolic pathology. We herein describe a case of diffuse calvarial hyperstosis. A 26-year-old man known to have end-stage renal disease on regular hemodialysis, tertiary hyperparathyroidism, extensive brown tumors, and severe developmental impairment with skeletal deformities was referred to us for macrocephaly. On examination, the patient was chairbound, with speech and motor developmental delay, and frontal bossing. Brain computed tomography revealed diffuse hyperstosis of the calvarium and facial bones expansion with multiple sclerotic and lytic areas, causing subsequent narrowing of the basilar skull foramina. Brain magnetic resonance imaging demonstrated an extensive expansile bone marrow abnormality in the calvarium and skull base. There was mild generalized prominence of cortical sulci and ventricular system. The findings were in keeping with his known hypermetabolic state and tertiary hyperparathyroidism. The patient was managed conservatively with regular follow-up in the clinic.