An update on the treatment of precocious puberty in McCune-Albright syndrome and testotoxicosis

McCune-Albright syndrome and testotoxicosis are rare forms of peripheral precocious puberty. Our understanding of the pathophysiology and mechanism of these diseases has significantly increased following identification of their underlying molecular etiology. However, their treatment remains challenging. We provide a review of the various treatment modalities used in both conditions with an update on recent trials using novel and promising pharmacological agents.     

Cushing's syndrome caused by nodular adrenal hyperplasia in children with McCune-Albright syndrome.

McCune-Albright syndrome consists of fibrous dysplasia of bone, café-au-lait skin pigmentation, and endocrine dysfunction (usually precocious puberty). Other endocrine abnormalities occur in a minority of patients, and of these, Cushing's syndrome is the least often recognized. We present 5 children (4 girls) with features of McCune-Albright syndrome who had Cushing's syndrome in the infantile period (<6 months). In 2 children spontaneous resolution occurred, but the remaining 3 required bilateral adrenalectomy. In addition, all 4 girls have experienced precocious puberty, and 3 children demonstrated radiologic evidence of nephrocalcinosis. Understanding of the underlying defect causing McCune-Albright syndrome emphasizes the importance of searching for other endocrine dysfunction in these children.     

Thyroid sonographic abnormalities in McCune-Albright syndrome

McCune-Albright syndrome (MAS) is characterised by the clinical triad precocious puberty, polyostotic bone dysplasia and caféau-lait skin lesions. Some studies have shown the possibility of multiple endocrinological disorders in this condition, especially thyroid disorders. We report the case of three girls with MAS and a heteromultinodular thyroid at sonography, despite the fact that they were clinically and biologically euthyroid. This raises the question of the follow-up and treatment of these lesions.     

Ovarian function in girls with McCune-Albright syndrome

We measured plasma estradiol levels and ovarian volumes in eight girls with precocious puberty due to McCune-Albright syndrome. Six girls had gonadotropin-independent ovarian estrogen secretion and two girls had pubertal gonadotropin levels. Mean ovarian volume in all patients was significantly greater than in normal prepubertal girls. Mean ovarian volumes of the girls with McCune-Albright syndrome overlapped the range found in girls with idiopathic central precocious puberty or central precocious puberty associated with central nervous system lesions. However, the degree of asymmetry between the right and left ovaries was significantly greater in girls with McCune-Albright syndrome. Asymmetry was due, for the most part, to the presence of large solitary cysts in the larger of the two ovaries. In the six girls with McCune-Albright syndrome and gonadotropin-independent precocious puberty, both mean ovarian volume and the degree of asymmetry between the right and left ovaries were significantly correlated with plasma estradiol. Serum follicle-stimulating hormone bioactivity was increased in two patients but did not vary with ovarian cyst size. Thyroid-stimulating hormone levels were normal but serum prolactin was slightly elevated in one of the six girls with gonadotropin-independent precocious puberty. Fluctuation in the size of unilateral ovarian cysts appears to result in changes in the plasma estradiol level, leading to advancement and spontaneous regression of secondary sexual characteristics and menses in girls with McCune-Albright syndrome. The cause of the cyst formation is unknown but may be related to periodic elevation of as yet undefined serum factors such as follicle-stimulating hormone bioactive substances.     

McCune-Albright syndrome: a longitudinal clinical study of 32 patients

We report the diagnostic clinical features and their long term evolution in 32 patients with McCune-Albright syndrome. Patient data are made up of two periods: the first, classified as personal history, is from birth until the time when the diagnosis of McCune-Albright syndrome was made; the second, classified as clinical observation, is from the first observation until the end of follow up. The total duration of these two periods was 9.6+/-2.9 yr; mean age at first observation was 5.7 yr (range 0.7-11 yr). The probability of manifesting main clinical signs according to age was calculated: almost all had skin dysplasia at birth, 50% probability of peripheral precocious puberty in females at 4 years and 50% of bone dysplasia at 8 years of age were found. Other clinical signs had diagnostic relevance when preceding the main signs leading to diagnosis of McCune-Albright syndrome even without specific genetic investigation. The most important clinical manifestations have different evolutions: skin lesions increase in dimensions according to body growth; precocious puberty in females evolves rapidly but periods of regression can be seen in some patients; bone dysplasia in most patients evolves with an increase both in the number of affected bones and in the severity of lesions.     

Laparoscopic management of ovarian cysts in peripheral precocious puberty of McCune-Albright syndrome

Ovarian cysts are common in peripheral precocious puberty in McCune-Albright syndrome (MAS). The clinical course of these cysts is unpredictable due to episodes of hyperestrogenism typical of MAS ovarian hyperfunction. In persistent and recurrent large ovarian cysts with sustained estrogen hypersecretion and relevant clinical disturbances (increased linear growth and bone age maturation, vaginal bleeding and psychological disturbances) treatment is mandatory. Experimental courses of estrogen-blocking drugs may have insufficient or nil therapeutic effects. In these cases and when molecular analysis is required to obtain MAS diagnosis as in isolated peripheral precocious puberty, surgery is the option. Laparoscopy minimizes surgical aggression and facilitates obtaining tissue samples for molecular analysis, and sometimes relieves hyperestrogenism with the excision of hyperactive ovarian areas. It can be conducted with trans-umbilical laparoscopic ovarian cystectomy (TULOC) before 3 years of age and with traditional techniques afterwards.     

Phenotypic testicular abnormalities and pubertal development in boys with McCune-Albright syndrome

Aim of this survey is to review the few available literature data on pathophysiologic and clinical aspects of pubertal development in boys with McCune-Albright syndrome (MAS). On the basis of such analysis, we concluded that:1) peripheral precocious puberty (PPP) is significantly more infrequent in boys than in girls; 2) the most common testicular abnormality at MAS presentation is macroorchidism, that may be either monolateral or bilateral; 3) macroorchidism is not always associated with clinical and biochemical evidence of PPP; 4) testicular microlothiasis is distinctly more frequent in boys with MAS than in those without MAS; 5) the available therapeutic schedules have to be adopted already at MAS presentation only in the cases with PPP.     

The NIH experience with precocious puberty: diagnostic subgroups and response to short-term luteinizing hormone releasing hormone analogue therapy

Between 1979 and 1983, 129 children (95 girls) with precocious puberty were referred to the National Institutes of Health and received treatment for at least 6 months with the long-acting LHRH analogue D-Trp6-Pro9-NEt-LHRH. The majority (107 of 129) of the children had central precocious puberty mediated by activation of the hypothalamic-pituitary-gonadal axis in association with hypothalamic hamartomas (24 of 107) or other central nervous system lesions (21 of 107), or idiopathic precocious puberty (62 of 107). Hypothalamic hamartomas or other central nervous system lesions were a frequent cause of central precocious puberty in girls (27 of 87), but idiopathic precocious puberty was still the most frequent diagnosis (63%). Idiopathic precocious puberty was uncommon in boys (6%). The patients with peripheral precocious puberty included six girls with McCune-Albright syndrome and six boys with familial male precocious puberty. These children had peripheral sex steroid secretion in the absence of hypothalamic-pituitary-gonadal axis maturation. The children with combined peripheral and central precocious puberty included nine children with congenital adrenal hyperplasia and one girl with a virilizing adrenal tumor. In the patients with central precocious puberty or combined peripheral and central precocious puberty, LHRHa therapy caused suppression of gonadotropin and sex steroid levels (P less than 0.001), stabilization or regression of secondary sexual characteristics, and decreases in growth rate and in the rate of bone age maturation (P less than 0.005). Patients with peripheral precocious puberty, however, had no significant change in gonadotropin or sex steroid levels, growth rate, or the rate of bone age maturation, and no improvement in secondary sexual characteristics. Thus, LHRHa is an effective treatment of central precocious puberty and combined peripheral and central precocious puberty, but is ineffective in the therapy of peripheral precocious puberty.     

McCune-Albright syndrome--the German experience

The classical McCune-Albright syndrome (MAS) consists of peripheral precocious puberty (PPP), fibrous bone dysplasia and café-au-lait spots. We conducted a survey among pediatric endocrinologists in Germany, Austria and Switzerland, most of them participating in the German Working Group for Pediatric Endocrinology (APE). Thirty-three physicians reported 58 patients. A detailed questionnaire yielded extensive data from 41 patients. Patients (36 females, 5 males) were diagnosed between the 4th week of life and 8 years. Symptoms included precocious puberty (37 patients), café-au-lait spots (35), fibrous bone dysplasia (32), hyperthyroidism (5), liver disease (5), phosphate wasting (4), GH hypersecretion (3), anemia in infancy (2), hyperprolactinemia (1), and Cushing's disease (1). Therapy of PPP included testolactone (15), tamoxifen (7), cyproterone acetate (CPA) (5), anastrozole (1) and exemestane (1). Testolactone, tamoxifen and CPA showed varying degrees of clinical remission; none was unanimously effective, but side effects were very rare. New aromatase inhibitors were not well validated in MAS. Eleven children received bisphosphonate therapy (pamidronate i.v. q 3 months) for fibrous bone dysplasia. Pamidronate was well tolerated, and pain improved when present, but data on preventive effects are not yet available. In conclusion, this survey describes a large cohort of patients with MAS, many with severe clinical problems, including major physical handicaps. Our results show that there is no 'gold standard' for the therapy of PPP; tested treatment regimens are not ideal, and new aromatase inhibitors need to be evaluated in controlled studies. Pamidronate was well tolerated, but preventive effects on bone dysplasia have not yet been proven.     

Recent advances in the diagnosis and treatment of precocious puberty

In the last two decades, the diagnosis and treatment of precocious puberty has undergone important changes. The use of supersensitive assays to determine gonadotropins and gonadal hormones has increased the sensitivity and decreased the number of blood samples required to assess the diagnosis. The introduction of gonadotropin-releasing hormone (GnRH) agonists produced a revolution in the diagnosis and treatment of this disorder. Recently, the use of long acting GnRH agonists improved the adherence of patients to medical treatment and decreased the need for uncomfortable repeated doses. The medications in the treatment of the GnRH independent causes of precocious puberty, and the important revelations in the pathophysiology of these disorders, have advanced our knowledge and management of the affected children.     

Precocious puberty: a follow up study.

Follow up of women previously seen between 1951 and 1971 with precocious puberty showed that most had normal menstrual cycles and that fertility was generally normal in those with ''constitutional'' precocious puberty. Three patients, however, with the McCune-Albright syndrome had not yet proved to be fertile.     

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.     

Recurrent ovarian cyst and mutation of the Gsα gene in ovarian cyst fluid cells: what is the link with McCune-Albright syndrome?*

Isolated peripheral precocious puberty due to recurrent ovarian cysts evokes a McCune-Albright syndrome (MAS). This syndrome associates endocrine dysfunction such as precocious puberty, polyostotic fibrous dysplasia, and ‘’café-au-lait“ skin lesions. We report the case of a 3-y-old girl who presented with peripheral puberty with extremely elevated oestradiol level, low LH and FSH levels, and an ovarian cyst that quickly resolved. Skeletal X-rays were normal and she had no café-au-lait spots. GnRH analogue treatment was ineffective. A second ovarian cyst appeared and was completely drained under ultrasonographic guidance. Molecular biological analysis performed on fluid cells revealed the Arg201→His mutation of the Gsa gene described in MAS. Percutaneous aspiration of simple ovarian cyst to detect‘’MAS” mutation is of interest in the diagnosis of recurrent ovarian cyst.     

外周性性早熟患儿的病因及预后随访

目的：探讨外周性性早熟的病因及预后。方法：应用简化的促性腺激素释放激素（GnRH）激发试验测定卵泡刺激素（FSH）及黄体生成素（LH）、雌二醇（E2）水平,并采用B超检查及骨龄检测等方法对125例外周性性早熟患儿进行病因诊断。随访病例102例,随访时间3个月至7.5年。结果：125例患儿的病因分布为：摄入外源性性激素80例,卵巢囊肿11例,McCune Albright 综合征11例,先天性肾上腺皮质增生症（CAH）5例,卵巢畸胎瘤、男性化肾上腺肿瘤、女性化肾上腺肿瘤、垂体柄肿瘤各1例,另有14例患儿病因尚不能确定。预后：摄入外源性性激素者随访72例,均在1～6个月性征消退;11例卵巢囊肿患儿中,8例1~4个月性征自行消退,但其中1例2年3个月后转为中枢性性早熟;1例囊肿切除术后性征消退;卵巢畸胎瘤者术后性征消退;McCune Albright 综合征及CAH者治疗后临床症状减轻,7例转为中枢性性早熟;2例肾上腺肿瘤术后性征消退;1例垂体柄肿瘤术后1年死亡。结论：外周性性早熟病因多样,详细的病史、体检、辅助检查有助于早期明确诊断,不同病因预后不同。     

Tamoxifen improved final height prediction in a girl with McCune-Albright syndrome: patient report and literature review

McCune-Albright syndrome (MAS) is characterized by gonadotropin-independent precocious puberty, café-au-lait spots on the skin and polyostotic fibrous dysplasia of bones. Treatment of precocious puberty (PP) in MAS should be considered in patients with poor predicted adult height (PAH). Treatment of gonadotropin-independent PP in MAS with ketoconazole, cyproterone acetate or testolactone, an aromatase inhibitor, does not appear to be always effective in slowing bon. maturation. We report here a Thai girl with MAS who received tamoxifen, one of the selective estrogen receptor modulators, for the management of advanced puberty and rapid bone maturation. Her pubertal progression, vaginal bleeding, growth rate and PAH improved during treatment with tamoxifen despite persistently elevated serum estradiol levels and an enlarged ovarian cyst.     

Clinical presentation of McCune-Albright syndrome in males

The aims of this study were: (a) to survey gender prevalence and clinical findings at diagnosis in a series of patients who manifested at the time of this study the classical triad of McCune-Albright syndrome (MAS); (b) to investigate whether clinical presentation of MAS in boys may be different from that in girls; (c) to confirm whether boys with MAS may show a peculiar picture of testicular microlithiasis (TM) by testicular ultrasonography (US). Twenty-six patients (10 boys) with the classical clinical manifestations of MAS were recruited for the present study from the database of the Italian Multicenter Study Group on MAS. Age at diagnosis of MAS was significantly lower in girls than in boys (p < 0.025). Whilst there was no difference in the prevalence of skin and bone fibrous dysplasia for the two groups, a significantly higher prevalence of peripheral precocious puberty (PPP) was found in girls (chi2 = 6.5, p < 0.025). Moreover, PPP onset was earlier in females than in males (2.8 +/- 2.3 vs. 6.9 +/- 2.7 years, p < 0.005). In one boy, aged 2.9 years, the first clinical manifestation of MAS was monolateral testicular enlargement in the context of a picture of classical PPP. US scanning of the testes, at the time of the present study, showed bilateral hyperechogeneic multiple spots, compatible with diagnosis of TM, in 6/10 boys. CONCLUSIONS: (a) MAS is slightly more frequent in females. (b) PPP in MAS is significantly more frequent and earlier in girls. (c) PPP in boys with MAS is generally associated with bilateral testicular enlargement, but monolateral macroorchidism may also be seen. (d) TM may be another marker for MAS in males.     

McCune-Albright syndrome associated with pituitary microadenoma: patient report

McCune-Albright syndrome (MAS) is a rare disorder characterized by the classic triad of precocious puberty, polyostotic fibrous dysplasia and café-au-lait spots. Additional endocrine abnormalities may also be present, including hyperthyroidism, growth hormone excess and hyperprolactinemia. The most commonly encountered endocrine dysfunction is gonadal hyperfunction. Gonadotropin-independent precocious puberty is typically the initial manifestation of MAS in girls. Ovarian cysts may be detected on pelvic ultrasound. Our patient was also found to have pituitary microadenoma, evidenced by dynamic magnetic resonance imaging.     

Tamoxifen treatment of progressive precocious puberty in a patient with McCune-Albright syndrome

Treatment of progressive precocious puberty in patients with McCune-Albright syndrome (MAS) has traditionally been with aromatase inhibitors, such as testolactone. However, the use of these agents has been characterized by problems with both efficacy and compliance. We report a case of MAS in which tamoxifen proved to be a successful alternative in the treatment of progressive precocious puberty. An African-American female presented with MAS at 2-5/12 years. Frequent menses, skeletal maturation and growth acceleration prompted initiation of therapy with testolactone at 22 mg/kg/d. Over the next 13 months, the patient's puberty advanced unchecked, despite progressive increases in the dose of testolactone. At age 4 years, medication was discontinued due to treatment failure. At 4-6/12 years, bone age was 10 years, predicted adult height was 137 cm, and monthly bleeding continued. Tamoxifen was then begun on an experimental basis. In response, the patient experienced immediate cessation of menses, and had an abrupt decrease in the rates of pubertal progression and linear growth. This patient has now been maintained on tamoxifen for over three years with no apparent adverse effects. GnRH analogue therapy was begun when the onset of central precocious puberty was noted. Predicted adult height has improved to 154 cm and growth velocity and skeletal maturation remain stable. Our results suggest that tamoxifen may have a valuable role in the treatment of precocious puberty in patients with MAS and may lead to superior results compared with those achieved with aromatase inhibitors.     

Clinical, endocrinological and radiography features in a child with McCune-Albright syndrome and pituitary adenoma

McCune-Albright syndrome is a rare syndrome presenting with polyostotic dysplasia, cafe-au-lait spots and multiple endocrinopathies that is very often combined with precocious puberty. We examined the clinical, endocrinological and radiological features in a boy with McCune-Albright syndrome and pituitary adenoma. X-rays, magnetic resonance (MRI) scan, whole body scintigraphy, single photon emission computer tomography (SPECT) and 3D-reconstruction from bone SPECT was performed to evaluate clinical improvement after treatment with sandostatin and pamidronic acid. After a six-month period of treatment with sandostatin and pamidronate, bone scintigraphy revealed significantly reduced activity. Treatment with bromocriptine and methimazole led to normalization of prolactin and thyroid hormone levels. Mobility of the patient improved. A significant improvement as a result of treatment with sandostatin and pamidronic acid was found in this patient with generalized fibrous dysplasia. So far, this condition has been treated with pamidronate only in adults, but severely affected children also benefit from this treatment regimen.     

McCune-Albright syndrome: molecular genetics

McCune-Albright syndrome (MAS) is a rare disorder characterized by the association of precocious puberty (mostly in girls), polyostotic fibrous dysplasia and café-au-lait pigmented skin lesions. In addition to this classical triad, several endocrine disorders, all due to autonomous hormonal hyperproduction, can also be associated, such as pituitary adenomas secreting growth hormone, hyperthyroid goiters, or adrenal hyperplasia. The distribution pattern of skin lesions and the sporadic character of MAS have led to the hypothesis that this syndrome is due to a dominant somatic mutation early in the course of development. Furthermore, the diverse endocrine hyperactivity syndromes observed in MAS have in common the involvement of cells that respond to extracellular signaling by activating the adenyl cyclase system. The identification of somatic mutations of the Gsalpha gene have shown that MAS is due to a post-zygotic activating mutation of the Gsalpha subunit leading to a mosaic distribution of cells bearing constitutively active adenyl cyclase activity. In all patients reported to date, the mutation is a substitution of the arginine residue at position 201 most often into histidine or cysteine. We present here some of the results we have obtained in studying 80 patients presenting one or several signs of MCA for identification of the Arg201 mutation. We used a PCR-based method that allows selective enrichment of mutated DNA. This study, and data in the literature during the last decade, has widened the definition of MAS. Affections as clinically different as somatotropic or thyrotropic adenomas, isolated polyostotic fibrous dysplasia, isolated peripheral precocious puberty and the classic McCune-Albright syndrome all appear to be elements of a wide spectrum of disease based on the same molecular defect. The developmental moment at which the mutation occurs determines both the number of tissues affected and the severity of expression. The application of tools from molecular genetics to the study of this syndrome confirms their essential contribution to a deeper understanding of endocrine pathologies.