McCune-Albright syndrome with gigantism and hyperprolactinemia

Acromegaly and McCune-Albright syndrome

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.

Polyostotic fibrous dysplasia with gigantism and huge pelvic tumor: a rare case of McCune-Albright syndrome

We report a rare case of polyostotic fibrous dysplasia on endocrine hyperfunction with elevated human growth hormone and normal serum level of prolactin. There were some differential points of gender, gigantism, endocrine function, and GNAS gene from McCune-Albright syndrome. Malignant transformation was suspected in the pelvic tumor from imaging because rapid growth of the tumor by imaging was observed; however, no malignant change occurred in this case.

McCune-Albright syndrome: clinical picture and natural history in children and adolescents

The classical triad of McCune-Albright syndrome (MAS) consists of polyostotic fibrous dysplasia (FD), skin hyperpigmentation (café-au-lait spots), and endocrine dysfunction, frequently seen in females as precocious puberty. Patients with MAS display mosaicism of activating somatic mutations of the alpha-subunit of Gs. Thus, the clinical presentation of each individual is dependent on the particular distribution of affected cells, causing a broad spectrum of endocrine and non-endocrine manifestations. Typical endocrinopathies are precocious puberty, hyperthyroidism, growth hormone excess, hyperprolactemia, and hypercortisolism. The onset of these manifestations is usually during infancy and childhood. Since specific treatment is required, the prognosis depends on the severity of each individual endocrine manifestation. Additionally, there are non-endocrine manifestations, such as fibrous dysplasia of bone (FD), renal phosphate wasting, and skin hyperpigmentation, i.e. café-au-lait spots. FD, mostly polyostotic, causes fractures needing surgical and orthopedic treatment. Since previous studies have suggested the overall prognosis of patients with McCune-Albright syndrome to be non-fatal, recent data have drawn our attention to non-endocrine affections, including hepatobiliary dysfunction and cardiac disease, which are probably an important risk factor for early death. In summary, the clinical picture in MAS is related to its mosaic nature, i.e. any cell, tissue and organ in any site of the body could be affected to varying degrees, ranging from one or two mild clinical signs with excellent long-term prognosis to a severe life-threatening multiorgan disease.

Endoscopic surgery for fibrous dysplasia of the sinonasal tract in pediatric patients

Fibrous dysplasia (FD) is a non-neoplastic, expansile lesion of unknown origin. In about one-fourth of cases this disorder affects the head and neck area, where the mandible and maxilla are the most frequently involved sites. Its localization to the ethmoid is a rare event. Since the disease slowly progresses, its management is delayed until significant clinical symptoms or non-well-tolerated aesthetic deformities are present. When required, surgery is the treatment of choice. Several external procedures have been used to manage the lesion, but recently, more conservative transnasal approaches have been proposed. We report the history of a 6-year-old boy with fibrous dysplasia of the ethmoid labyrinth that underwent successful transnasal endoscopic removal. Furthermore, an analysis of the literature is presented with particular emphasis on clinical picture, diagnosis, and treatment of this rare illness.

Clinical implications of genetic defects in G proteins. The molecular basis of McCune-Albright syndrome and Albright hereditary osteodystrophy

Inactivating and activating mutations in the gene encoding G alpha s (GNAS1) are known to be the basis for 2 well-described contrasting clinical disorders, Albright hereditary osteodystrophy (AHO) and McCune-Albright syndrome (MAS). AHO is an autosomal dominant disorder due to germline mutations in GNAS1 that decrease expression or function of G alpha s protein. Loss of G alpha s function leads to tissue resistance to multiple hormones whose receptors couple to G alpha s. By contrast, MAS results from postzygotic somatic mutations in GNAS1 that lead to enhanced function of G alpha s protein. Acquisition of the activating mutation early in life leads to a more generalized distribution of the mosaicism and is associated with the classic clinical triad of polyostotic fibrous dysplasia, endocrine hyperfunction, and café au lait skin lesions described in MAS. Acquisition of a similar activating mutation in GNAS1 later in life presumably accounts for the restricted distribution of the gsp oncogene, and is associated with the development of isolated lesions (for example, fibrous dysplasia, pituitary or thyroid tumors) without other manifestations of MAS. Tissues that are affected by loss of G alpha s function in AHO are also affected by gain of G alpha s function in MAS, thus identifying specific tissues in which the second messenger cAMP plays a dominant role in cell growth, proliferation, or function. Further investigations of the functions of G alpha s and other members of the GTPase binding protein family will provide more insight into the pathogenesis and clinical manifestations of human disease.

Octreotide therapy of growth hormone excess in the McCune-Albright syndrome

We report a patient with the McCune-Albright syndrome and growth hormone excess. Biochemical evaluation demonstrated characteristic changes typical of acromegaly, and an unusual pattern of delayed somatotropin response to hGHRH40, not previously described in this syndrome. Therapeutic trial of low-dose octreotide successfully reversed his growth hormone excess, whereas bromocriptine failed to reduce growth hormone levels. Previous reports of acromegaly and McCune-Albright syndrome are reviewed, and the unique features of this case discussed.

Effects of cyproterone acetate, LHRH agonist and ovarian surgery in McCune-Albright syndrome with precocious puberty and galactorrhea

We have studied the endocrinological pattern in a girl with McCune-Albright syndrome. The young patient showed: normal prepubertal serum levels of gonadotropins, fluctuating estrogen concentrations, which sometimes were similar to the levels in adult women of fertile age, hyperprolactinemia with galactorrhea, ovarian cysts. The effects of treatment with antiandrogen drug, cyproterone acetate, and of a LHRH agonist, buserelin (less than D-Ser[TBU(8)6-des-gly NH2.10 greater than LHRH ethylamide), were studied. Cyproterone acetate with or without buserelin did not fully suppress estradiol concentrations. On the other hand, surgical resection of these cysts resulted in both clinical and endocrinological remission. It is likely that in this case of McCune-Albright syndrome precocious puberty was a result of ovarian estrogen secretion, while pubertal activation of the hypothalamus-pituitary axis was absent. Hyperprolactinemia, which appeared after the beginning of the combined therapy with buserelin and cyproterone acetate, was probably due to the elevated estrogen levels.