Precocious puberty in boys

Diagnosis and management of precocious sexual maturation: an updated review

The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. It is classified as central precocious puberty when premature maturation of the hypothalamic-pituitary-gonadal axis occurs, and as peripheral precocious puberty when there is excessive secretion of sex hormones, independent of gonadotropin secretion. Precocious sexual maturation is more common in girls, generally central precocious puberty of idiopathic origin. In boys, it tends to be linked to central nervous system abnormalities. Clinical evaluation should include a detailed history and physical examination, including anthropometric measurements, calculation of growth velocity, and evaluation of secondary sexual characteristics. The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. Hormonal assessment and imaging are required for diagnosis and identification of the etiology. Genetic testing should be considered if there is a family history of precocious puberty or other clinical features suggestive of a genetic syndrome. Long-acting gonadotropin-releasing hormone analogs are the standard of care for central precocious puberty management, while peripheral precocious puberty management depends on the etiology.Conclusion: The aim of this review is to address the epidemiology, etiology, clinical assessment, and management of precocious sexual maturation. What is Known: • The main sign to suspect the onset of puberty is breast tissue development (thelarche) in girls and testicular enlargement (≥4 mL) in boys. The classic definition of precocious sexual maturation is the development of secondary sexual characteristics before 8 years of age in girls and before 9 years of age in boys. • Long-acting gonadotropin-releasing hormone agonist (GnRHa) is the standard of care for CPP management, and adequate hormone suppression results in the stabilization of pubertal progression, a decline in growth velocity, and a decrease in bone age advancement. What is New: • Most cases of precocious sexual maturation are gonadotropin-dependent and currently assumed to be idiopathic, but mutations in genes involved in pubertal development have been identified, such as MKRN3 and DLK1. • A different preparation of long-acting GnRHa is now available: 6-month subcutaneous injection.

Training using a simulation-based workshop reduces inaccuracies in estimations of testicular volume

OBJECTIVES

Measuring testicular volume (TV) by orchidometer is routine in the clinic when staging male puberty. We have developed a simulation model for TV estimation and investigated whether training medical students, using a workshop with simulation models, could improve the accuracy and reliability of TV estimation.

METHODS

All participating medical students watched a video representing standard undergraduate training in male pubertal assessment. Volunteers were then randomised directly to assessment or to attend a workshop consisting of a further video and four stations contextualising and practising the skills required for TV estimation, prior to assessment. Three child mannequins displaying testes of 3 mL, 4 mL (twice), 5, 10 and 20 mL were used for assessment. Participants were asked to return a fortnight later for repeat assessment to assess intra-observer reliability, the effect of repeated examinations on accuracy and time on skill retention.

RESULTS

Ninety students participated (55F), 46 attended the workshop and were considered "trained". There was no difference between the groups in numbers of correct estimations (29% trained, 27% untrained, p=0.593). However, the trained group's estimations were closer to the true volume, with more from the trained group one bead away (p=0.002) and fewer more than three beads away from the true volume (p<0.001), compared to the untrained group. Trained participants were more accurate at the second assessment (n=80) (p<0.001) and had greater intra-observer reliability (p=0.004).

CONCLUSIONS

Overall TV estimation accuracy was poor. Workshop-style training improved accuracy, reliability and retention of skill acquisition and could be considered as a useful learning tool.

High Frequency of MKRN3 Mutations in Male Central Precocious Puberty Previously Classified as Idiopathic

BACKGROUND/AIMS

Recently, loss-of-function mutations in the MKRN3 gene have been implicated in the etiology of familial central precocious puberty (CPP) in both sexes. We aimed to analyze the frequency of MKRN3 mutations in boys with CPP and to compare the clinical and hormonal features of boys with and without MKRN3 mutations.

METHODS

This was a retrospective review of clinical, hormonal and genetic features of 20 male patients with idiopathic CPP evaluated at an academic medical center. The entire coding regions of MKRN3, KISS1 and KISS1R genes were sequenced.

RESULTS

We studied 20 boys from 17 families with CPP. All of them had normal brain magnetic resonance imaging. Eight boys from 5 families harbored four distinct heterozygous MKRN3 mutations predicted to be deleterious for protein function, p.Ala162Glyfs*14, p.Arg213Glyfs*73, p.Arg328Cys and p.Arg365Ser. One boy carried a previously described KISS1-activating mutation (p.Pro74Ser). The frequency of MKRN3 mutations among these boys with idiopathic CPP was significantly higher than previously reported female data (40 vs. 6.4%, respectively, p < 0.001). Boys with MKRN3 mutations had typical clinical and hormonal features of CPP. Notably, they had later pubertal onset than boys without MKRN3 abnormalities (median age 8.2 vs. 7.0 years, respectively, p = 0.033).

CONCLUSION

We demonstrated a high frequency of MKRN3 mutations in boys with CPP, previously classified as idiopathic, suggesting the importance of genetic analysis in this group. The boys with CPP due to MKRN3 mutations had classical features of CPP, but with puberty initiation at a borderline age.

Gonadotrophin-independent precocious puberty associated with later diagnosis of testicular embryonal carcinoma

BACKGROUND

Testicular tumours are very rare in children. Germ cell tumours (GCTs) account for the majority of testicular tumours in young people, and embryonal carcinomas are a common component of GCTs in adolescents.

CASE PRESENTATION

A 9.8-year-old boy presented with the development of pubic and facial hair over a period of 2 years. He had a growth spurt and examination revealed pubertal staging of G4 P4 A2 with a 6-mls testis on the right and a 4-mls testis on the left. Investigations revealed suppressed gonadotrophins, a testosterone concentration of 10.3 nmol/l and normal 17-hydroxyprogesterone and adrenal androgen levels. Tumour markers were negative. Following treatment with anastrazole, his height velocity slowed down. At the age of 13.7 years, his treatment was stopped. At the age of 14.8 years, he presented with a grossly enlarged right testis and elevated beta human chorionic gonadotrophin (>1,400 IU/l). He underwent right orchidectomy and histology revealed an embryonal carcinoma with no vascular invasion. Analysis of luteinizing hormone/choriogonadotrophin receptor revealed no mutation.

CONCLUSION

We present a case of testicular embryonal carcinoma in a boy who had presented 5 years before with features suggestive of gonadotrophin-independent precocious puberty.

Precocious puberty in children: A review of imaging findings

OBJECTIVES

This review was aimed at determining the imaging findings in patients with precocious puberty.

RESULTS

Within a period of 8 years (from 2002 to 2010) there were 53 patients diagnosed with precocious puberty. Out of the 53 patients, 37 had undergone diagnostic imaging to detect the possible organic causes of precocious puberty. Imaging findings were positive in 31 patients and out of that, 3 patients had 2 findings each (34 abnormalities). Of the patients with positive imaging findings, central precocious puberty (gonadotrophin-dependent) was more common (81%; 25/31) and the causes included: tuber cinereum hamartoma (n = 10), glioma (n = 6), pineal gland tumour (n = 4), hydrocephalous (n = 3), arachnoid cyst (n = 2) and others (n = 3). Peripheral precocious puberty (gonadotrophin-independent) causes included: testicular adrenal rest tumour (n = 3), adrenal carcinoma (n = 1), ovarian granulosa thecal cell tumour (n = 1), and tuberous sclerosis (n = 1).

CONCLUSION

Positive imaging findings were observed in 84% (31/37) of the subjects. Hypothalamic hamartoma was the most common imaging finding in central precocious puberty while testicular adrenal rest tumour was the most common imaging finding in peripheral precocious puberty.

La pubertad precoz central en niños está asociada a una elevada prevalencia de patología orgánica

INTRODUCTION

The incidence of central precocious puberty (CPP) is lower in boys than in girls; however, the presence of organic disease is more common in boys.

OBJECTIVES

To investigate the percentage of CPP secondary to organic disease in boys and to analyze their clinical and biological characteristics at diagnosis, during follow-up, and at the end of therapy.

PATIENTS AND METHODS

Eight boys with a diagnosis of CPP treated with triptorelin every 28 days were included. Age, height in standard deviation (SD), body mass index (BMI) in SD, growth velocity in SD, bone age (Greulich and Pyle), predicted height (Bayle-Pinneau), and target height were analyzed. Testicular volume was measured (according to Prader standards) and peak lutein hormone (LH) values and testosterone levels were determined after gonadotropin-releasing hormone (GnRH) stimulus.

RESULTS

Seventy-five percent of the patients with CPP had organic disease. After treatment with triptorelin, growth reduction significantly decreased. In contrast, no changes were seen in the difference between bone age and chronological age, due to the slight difference found at diagnosis. Likewise, during treatment, there was no LH peak and testosterone levels were lower than 0.5 ng/ml in response to GnRH stimulus. No changes were observed in weight or BMI. Three patients reached an adult height similar to their genetic height and their predicted height, as estimated by the Bayle-Pinneau method.

CONCLUSIONS

1. Among boys with CPP we found a substantial number of patients with organic disease. 2. Adult height after treatment with triptorelin can reach the normal range. 3. Determination of testosterone levels can be useful in the follow-up of these children during treatment.

Adult leydig cell tumors of the testis caused by germline fumarate hydratase mutations

CONTEXT

Leydig cell tumors (LCTs) are the most common non-germ-cell neoplasms of the testis. LCTs are often hormonally active and can result in precocious virilization or in adult feminization. We identified an LCT in an affected individual from a kindred with hereditary leiomyomatosis and renal cell cancer (HLRCC) and a germline fumarate hydratase (FH) mutation (N64T).

OBJECTIVE

Our objective was to investigate the role of FH mutations in predisposition to LCTs.

DESIGN

We tested for pathogenic effects of the N64T mutation and screened an additional 29 unselected adult LCTs for FH alterations. We also tested these LCTs for mutations in two genes, the LH/choriogonadotropin receptor (LHCGR) and the guanine nucleotide-binding protein alpha (GNAS) that had been implicated in LCT tumorigenesis.

RESULTS

No mutations were found in GNAS, and one tumor had a LHCGR somatic substitution. In addition to the HLRCC case with the N64T germline FH mutation, we identified one other LCT with a previously unreported FH mutation (M411I). Both LCTs from these patients showed loss of the wild-type FH allele. Immunohistochemical and in situ hybridization analyses demonstrated activation of the hypoxia/angiogenesis pathway not only in the tumors belonging to the FH mutation carriers but also in several other mutation-negative LCTs.

CONCLUSIONS

Our study shows that some LCTs are caused by FH mutations and represents one of the first reports of germline mutations in any type of adult testicular tumor.

Central precocious puberty: current treatment options

Central precocious puberty (CPP) is characterized by early pubertal changes, acceleration of growth velocity, and rapid bone maturation that often result in reduced adult height. An onset of pubertal signs before the age of 8 years in girls and 9 years in boys should always be evaluated. A combination of clinical signs, bone age, pelvic echography in girls, and hormonal data are required to diagnose CPP and make a judgment concerning progression and prognosis. Not all children with apparently true CPP require medical intervention. The main reasons for treatment are to prevent compromised adult height and to avoid psychosocial or behavioral problems. The need for treatment for auxologic reasons is based on estimation of predicted adult height, with the finding of a reduced height potential, which may require a follow-up. Indication for treatment on the basis of psychologic and behavioral anomalies has to be determined on an individual basis. The main short-term aims of therapy are to stop the progression of secondary sex characteristics and menses (in girls) and to treat the underlying cause, when known. Long-term goals are to increase final adult height and to promote psychosocial well-being. Once it has been decided that treatment is appropriate, it should be initiated immediately with depot gonadotropin-releasing hormone (GnRH) agonists. The effective suppression of pituitary gonadal function is achieved with these compounds in practically all CPP patients. Long-term data are now available from 2 decades of GnRH agonist treatment for patients with CPP. Treatment preserves height potential in the majority of patients (especially in younger patients) and improves the final adult height of children with rapidly progressing CPP, with a complete recovery of the hypothalamic-pituitary-gonadal axis after treatment. GnRH agonist treatment using depot preparations is useful and has a good safety profile, with minimal adverse effects and no severe long-term consequences. Although further data are need, there may be a role in the future for combining somatropin (growth hormone) and GnRH agonist treatment for some patients with significantly impaired growth velocity. The introduction of GnRH antagonists is likely to improve the treatment options for CPP.