What are the manifestations of McCune-Albright syndrome (MAS)?

Updated: Jan 05, 2021
  • Author: Gabriel I Uwaifo, MD; Chief Editor: George T Griffing, MD  more...
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The clinical presentation of MAS is highly variable, depending on which of the various potential components of the syndrome predominate. Major manifestations include the following:

  • Precocious puberty (typically gonadotropin-independent) - This includes breast development, genital maturation (with or without pubic hair growth), increased height velocity, and macroorchidism [5]

  • Café-au-lait pigmentation - This consists of spots ranging from light brown to dark brown in color, often displaying a segmental distribution, and frequently predominating on one side of the body without crossing the midline; these spots must be differentiated from those characteristic of neurofibromatosis (NF)

  • PFD - Multiple pathologic fractures may be prominent early in the history; in many cases, bony involvement is found to predominate clinically on 1 side; potential presenting features include gait anomalies, visible bony deformities (including abnormal bone growths of the skull), bone pain, and joint stiffness with pain

  • Hyperthyroidism (rare without several other features of MAS also being present) - Findings may include tachycardia, arrhythmias (mostly supraventricular), hypertension, hyperthermia, tremor, sleeplessness, weight loss, or (in infants) failure to thrive

Other possible manifestations include the following:

  • Cushing syndrome

  • Growth hormone (GH) excess (gigantism and acromegaly)

  • Acromegaly

  • Ovarian cysts

  • Pituitary tumors

  • Thyroid tumors

  • Hypophosphatemia (hypophosphatemic rickets)

  • Hypogonadotropic hypogonadism, particularly in the setting of hyperprolactinemia

See Clinical Presentation for more detail.

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