Endocrine Abstracts

Introduction: Craniofacial fibrous dysplasia, characteristic of McCune-Albright syndrome (MAS), is usually present in patients with MAS related GH excess, and complicates their neurosurgical approach. We describe a 21-year-old male with severe craniofacial fibrous dysplasia and acute obstructive hydrocephalus due to a 39×35 mm cystic lesion in the third ventricle that occluded Monro’s foramina, in whom MAS and long-term untreated acromegaly were discovered.

Methods: This report describes the presentation, diagnostic process, treatments and outcome of a young male patient with abnormal dysplastic growth of craniofacial bone structures, that reduced the optic canal and orbits, and occupied completely the sphenoid sinus, who presented with rapidly progressive headache. It also includes the results of a detailed GNAS genetic study in blood, pituitary, and bone tissues.

Results: Surgical resection of the tumor using a transcranial transcortical-transventricular approach and opening of the suprasellar cistern resolved the hydrocephalus and associated symptoms. Histologic and genetic studies of the extracted tissues, together with a hormonal evaluation, confirmed the presence of a colloid cyst combined with a GH-secreting pituitary adenoma with a Ki 67 proliferative index of 9%, and MAS. The GNAS gene p.Arg201His mutation in mosaicism was present in the pituitary tissue, but was not found in blood and decalcified paraffin-embedded bone tissue. Adequate control of his GH hypersecretion with somatostatin analogs and cabergoline was achieved.

Conclusion: This is the first reported case of a colloid cyst of the third ventricle in a patient with MAS. Our results suggest that MAS related long-standing GH excess may promote abnormal progressive dysplastic growth of craniofacial bones that might force any entrapped intrasellar lesion to grow upwards to the third ventricle, and should be ruled out and treated promptly in young patients with fibrous dysplasia. Hormonal evaluation and multidisciplinary approach before any surgery in these patients may help to optimize surgical results and guide further treatments to avoid long-term deleterious impact of hyperfunctioning endocrinopathies.