Which physical findings are characteristic of precocious puberty in McCune-Albright syndrome (MAS)?

Updated: Jan 17, 2019
  • Author: Gabriel I Uwaifo, MD; Chief Editor: George T Griffing, MD  more...
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Answer

Patients with precocious puberty invariably are taller as children. However, as a result of a combination of precocious puberty, recurrent fractures, and hypophosphatemic rickets, the majority of patients with MAS have a final height below that of their peers and below their projected midparental height. An important scenario in which a patient with MAS attains normal height is that in which there is a coexisting GH excess (a clinical pearl that aids in diagnosis in these particular cases). [5]

Precocious puberty in girls with MAS is indicated by the appearance of signs of excess estrogen for age, including breast development, genital maturation, and increased height velocity. Pubic hair growth may or may not be present. Both breast diameter and Tanner staging should be recorded at each clinic visit as a gauge of ongoing estrogen exposure.

If necessary, genital maturation can be determined by examining the vaginal mucosa. A pink mucosa with mucous covering is consistent with estrogen stimulation, whereas a glistening red appearance is indicative of a thin, non–estrogen-stimulated mucosa.

Examination of the vaginal mucosa should be performed with extreme care to avoid traumatizing the patient. Frequently, the introitus can be examined with the patient lying on her back with heels together and legs externally rotated. Very gentle traction of the labia majora may be necessary. Bimanual or speculum examinations should not be attempted. Only trained individuals should perform more detailed vaginal examinations with the patient under light general anesthesia.

Testicular enlargement (macroorchidism) occurs in males with MAS. Although it is usually bilateral and occurs against a context of sexual precocity, this is not always the case. A 4.6-year-old boy with unilateral macroorchidism without sexual precocity or other MAS pathology has been described. [31]


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