Severe Fibrous Dysplasia in McCune-Albright Syndrome: A Need for Continuous Surveillance.

INTRODUCTION: McCune-Albright syndrome (MAS) is a rare condition, in which GNAS mutations affect multiple organs. Fibrous dysplasia (FD), affecting only one or multiple skeletal territories, may severely affect craniofacial structures. Concomitant occurrence of acromegaly aggravates skull deformity, leading to eye, ear, and posterior cranial fossa compromise. CASE PRESENTATION: A 30-year-old man diagnosed with MAS at the age of 3 developed almost all known complications of the syndrome. The craniofacial component of his polyostotic FD increased over time, aggravated by difficult to control acromegaly. Acute onset of severe headache and neurologic compromise, caused by subarachnoid haemorrhage, caused his demise. Post-mortem examination revealed a meningeal artery aneurysm caused by disruption of the intracranial vasculature by severe bone disease. Adrenal histology revealed nodular hyperplasia without clinical evidence of hypercortisolism. DISCUSSION: The post-mortem findings described aid understanding of the multiorgan involvement of MAS, providing new insights into possible pathogenetic mechanisms underlying the systemic effects of GNAS mutations, and highlight a need for systematic surveillance for cerebrovascular changes in craniofacial FD that may be amenable to intervention to avoid catastrophic outcome.