Delayed and Precocious Puberty

Abstract

Delayed and precocious puberty are distressing conditions that can have serious long-term effects, and may also be the presenting manifestation of serious underlying medical conditions affecting the hypothalamic-pituitary-gonadal axis. An understanding of the various disorders of sexual development is essential for rational radiological investigation and the interpretation of its findings. True (central) precocious puberty and precocious pseudopuberty must be distinguished from the variants of precocious sexual development that may have similar early clinical features (isolated premature menarche, isolated premature thelarche and thelarche variant, and isolated premature adrenarche). Before initiating radiological investigations, full clinical assessment is essential. Radiological investigations are important in both delayed and precocious puberty to provide additional indicators of the stage of puberty. The most important radiological indicators of stage of puberty are radiographic estimation of bone age, and ultrasound of the pelvis. Ultrasound assessment of the stage of development of the uterus and ovaries is a valuable tool in the diagnosis of precocious puberty in girls and in differentiating between true precocious puberty and other types of early puberty. Serial ultrasound is also useful to assess the response to treatment. Delayed and precocious puberty may be caused by intracranial pathology which disrupts the hypothalamic-pituitary axis. True precocious puberty in girls is idiopathic or familial in over 80% of cases, but cranial MRI is necessary to exclude CNS abnormalities. Hypothalamic hamartoma is the most common intracranial tumour identified in true precocious puberty. CNS lesions that may result in either delayed or precocious puberty include neurofibromatosis type 1 (usually in association with an optic pathway glioma), craniopharyngioma, and suprasellar lesions such as arachnoid cysts and epidermoid cysts. In pseudo-precocious puberty, pelvic ultrasound should be undertaken to assess the stage of development of the uterus and ovaries; the ovaries should also be carefully examined for evidence of an autonomously functioning ovarian cyst or tumour that secretes oestrogen (granulosa-theca cell tumours are the most common). A comprehensive ultrasound examination of the whole of the abdomen should also be undertaken, with particular attention to the adrenals for evidence of an adrenal tumour or diffuse bilateral hypertrophy.