Abnormal hypothalamic-pituitary function in polyostotic fibrous dysplasia.

Area of Science:

• Endocrinology
• Neuroscience
• Genetics

Background:

• McCune-Albright syndrome is a rare genetic disorder characterized by polyostotic fibrous dysplasia, café-au-lait spots, and precocious puberty.
• Craniofacial bone lesions, such as leontiasis ossea, can occur and potentially impact nearby structures like the pituitary gland.

Observation:

• Two patients with polyostotic fibrous dysplasia and leontiasis ossea presented with features suggestive of McCune-Albright syndrome.
• Endocrinological studies revealed abnormal 24-hour plasma growth hormone and prolactin secretion patterns.
• One patient exhibited elevated mean plasma cortisol, though the diurnal secretion pattern was normal. TSH response to TRH was absent, but prolactin and GH increased after TRH stimulation.

Findings:

• Patients displayed persistent measurable plasma growth hormone with preserved sleep-augmented rises.
• Abnormal mean plasma prolactin concentrations and 24-hour secretory patterns were observed.
• Despite normal basal levels of LH, FSH, TSH, T4, and T3, TRH stimulation affected GH and prolactin, not TSH.

Implications:

• The findings strongly suggest hypothalamic-pituitary dysfunction in patients with McCune-Albright syndrome and craniofacial involvement.
• This dysfunction may contribute to the complex hormonal imbalances seen in the syndrome.
• Further research is warranted to elucidate the mechanisms and clinical significance of pituitary involvement in McCune-Albright syndrome.