Acromegaly and McCune-Albright syndrome

Abstract

Background: McCune-Albright syndrome (MAS) includes the triad of poly/monostotic fibrous dysplasia, café-au-lait spots, and hyperfunctioning endocrinopathies. Acromegaly affects around 20% of MAS patients.

Aims: The objective was to review all reported cases of acromegaly associated with MAS.

Methods: All studies and case reports of acromegaly in patients with MAS were systematically sought in the world literature up to January 2013. We also included new data (from three unreported cases) and updated data on 23 previously reported patients from our two centers.

Results: We reviewed the cases of 112 patients (65 males). Mean age at diagnosis of acromegaly was 24.4 years (range, 3-64). Among the 40 pediatric patients, 23 (57%) had precocious puberty. GH/IGF-1 excess was suggested by accelerated growth in 85% of pediatric cases. Acromegaly was almost always associated with skull base fibrous dysplasia. Modern imaging techniques (computed tomography or magnetic resonance imaging) revealed an adenoma in 54% of the patients (macroadenoma in more than two-thirds). Median GH levels and mean IGF-1 SD score at diagnosis were 57 μg/L (2.8 to 291 μg/L) and 8 (2.3 to 24), respectively. Hyperprolactinemia was present in 81% (mean, 149 μg/L; range, 21-600). Pituitary surgery, performed in 25 cases, very rarely cured the GH/IGF-1 excess. Somatostatin analogs improved GH/IGF-1 levels in most patients but achieved control of acromegaly in only 17 (30%) of 56 patients. Pegvisomant achieved normal IGF-1 levels in 10 of 13 cases.

Conclusion: Acromegaly, which is present in 20-30% of patients with MAS, raises particular diagnostic and therapeutic issues.

Figure 1.

Visualization by MRI, in coronal view (A) and sagittal view (B) of a macroadenoma (arrow) surrounded by cranial fibrous dysplasia (star) in a patient with MAS and acromegaly.

Figure 2.

Visualization by MRI, in coronal view (A) and sagittal view (B) of a microadenoma (arrow) surrounded by cranial fibrous dysplasia (star) in a patient with MAS and acromegaly.