Precocious Puberty in Males

What is Precocious Puberty in Males?

Boys who begin to mature sexually before age 10 exhibit one of two forms of precocious puberty, also called isosexual precocity. The most common form is true precocious puberty, characterized by early maturation of the hypothalamic-pituitary-gonadal axis, development of secondary sex characteristics, gonadal development, and spermatogenesis. Pseudoprecocious puberty induces development of secondary sex characteristics without gonadal development. Boys with true precocious puberty reportedly have fathered children as early as age 7.

In most boys with precocious puberty, sexual characteristics develop in essentially normal sequence. These children function normally when they reach adulthood.

Causes of Precocious Puberty in Males

True precocious puberty may be idiopathic (constitutional) or cerebral (neurogenic). In some patients, idiopathic precocity may be genetically transmitted as a dominant trait. Cerebral precocity results from pituitary or hypothalamic intracranial lesions that cause excessive secretion of gonadotropin.

Pseudoprecocious puberty may result from testicular tumors (hyperplasia, adenoma, or carcinoma) or from congenital adrenogenital syndrome. Testicular tumors create excessive testosterone levels; adrenogenital syndrome creates high levels of adrenocortical steroids. Deficiencies of 11β-hydroxylase or 21-hydroxylase may also cause precocious puberty in males.

Signs & Symptoms of Precocious Puberty in Males

Males, onset is before age 10; boys grow facial, underarm, and pubic hair; growth, including that of the penis, accelerates; and behavior becomes more aggressive.

Gonadotropin-independent precocious puberty usually affects boys, who have low levels of gonadotropin.

In boys, the Signss of precocious puberty before 9 years of age include:

• rapid height growth - a growth "spurt"
• voice deepening
• "mature" body odor
• acne
• enlargement of the testicles or penis

Diagnostic tests

In true precocious puberty:

• Serum luteinizing hormone, follicle-stimulating hormone, and corticotropin levels are elevated.
• Plasma testosterone levels increase to adult levels.
• Ejaculate evaluation may reveal live spermatozoa.
• Brain scan, magnetic resonance imaging, skull X-rays, and EEG may be used to detect central nervous system tumors.
• Skull and hand X-rays show advanced bone age.

In pseudoprecocious puberty:

• Chromosomal karyotype analysis may demonstrate an abnormal pattern of autosomes and sex chromosomes.
• Adrenal androgen levels are elevated.

Treatment

Boys with idiopathic precocious puberty generally require no medical treatment and except for stunted growth. experience no physical complications in adulthood. Psychological counseling is important. Medroxyprogesterone may be used to inhibit gonadotropin secretion.

When precocious puberty is caused by tumors, the prognosis is discouraging. Brain tumors require neurosurgery but commonly resist treatment and may be fatal. Radiation therapy is used when indicated. A hypothalamic hamartoma requires a gonadotropinreleasing hormone (Gn-RH) analogue; idiopathic neurogenic precocious puberty demands a long-acting Gn-RH analogue. A patient with testicular tumor may be treated by removing the affected testis (orchiectomy). Malignant tumors also necessitate chemotherapy and lymphatic radiation therapy.

When precocious puberty results from an autosomal dominant disorder. the goal of treatment is to block androgen and estrogen stimulation. Spironolactone and testolactone are sometimes used. The antifungal agent ketoconazole is being tested for its inhibitory effect on the biosynthesis of adrenal and gonadal steroids.

Adrenogenital syndrome that causes precocious puberty may respond to lifelong therapy with glucocorticoids (cortisol) to inhibit corticotropin production.

Prevention Tips

Precocious puberty cannot be prevented.