Treatment of Pituitary Gigantism in McCune-Albright Syndrome with Craniofacial Fibrous Dysplasia
Pituitary gigantism occurring in the setting of McCune-Albright syndrome (MAS) — caused by a postzygotic activating GNAS mutation — is a rare and clinically distinct presentation, particularly when accompanied by craniofacial fibrous dysplasia. Early-onset hormonal excess in this context requires a specific management approach.
In MAS, mosaicism for a postzygotic activating mutation of GNAS leads to variable and diverse pathology affecting multiple tissues — classically including fibrous dysplasia of bone, hormonal over-activity, and café au lait macules. Pituitary involvement can manifest in children and adolescents as early-onset acromegaly, leading to pituitary gigantism. The presence of craniofacial fibrous dysplasia significantly alters the treatment landscape.
Because craniofacial fibrous dysplasia makes surgical cure exceptionally difficult in this population, medical therapy is central to management. A first-generation somatostatin analog forms the cornerstone of the approach. The primary therapeutic goal is hormonal control, assessed through IGF-1. The complete protocol — including agent selection, monitoring parameters, and the full clinical algorithm — is available in the structured regimen below.
References
DOI: 10.1016/B978-0-12-814537-1.00002-6
In MAS, mosaicism for a postzygotic activating mutation of GNAS leads to variable and diverse pathology affecting multiple tissues, classically, fibrous dysplasia of the bone, hormonal over-activity, and distinctive café au lait macules.
Acromegaly forms a part of the MAS spectrum and rarely can have an early onset in children/adolescents, leading to pituitary gigantism.
Due to the difficult approach through skull base fibrous dysplasia (which can be highly vascular as well as thick) and the diffuse pituitary disease, surgical cures only occur exceptionally and medical therapy is necessary.
The response to first-generation somatostatin analogs in terms of hormonal control in the Salenave et al. series was similar to that of unselected acromegaly patients (14% 46%).
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