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Genetic and Rare Diseases Information Center (GARD)

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Other Names for this Disease
  • Drug-induced gigantomastia (subtype)
  • Gestational gigantomastia (subtype)
  • Idiopathic gigantomastia (subtype)
  • Juvenile gigantomastia (subtype)
  • Macromastia
More Names
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Gigantomastia is a rare condition that is characterized by excessive breast growth that may occur spontaneously, during puberty or pregnancy, or while taking certain medications.[1][2] To date, there is no universally accepted definition for gigantomastia; however, Dancey et al. (2007) state that a review of the medical literature suggests that definitions range from a D-cup bra size to breast enlargement requiring reduction of over 0.8 - 2 kg, which is equivalent to about 1.75 - 4.5 pounds. The exact cause of gigantomastia has not been determined. Nonetheless, the following theories have been proposed to explain gigantomastia: (1) end-organ hypersensitivity (a condition in which the breast tissue is more sensitive to hormones circulating in the body), (2) autoimmune issues, (3) high IGF-1 (insulin growth factor-1, a hormone involved in regulating bone growth) and (4) hyperprolactanemia (high levels of prolactin). [3] Gigantomastia has been noted as a side effect of treatment with certain medications like D-pencillamine and in one case as an apparently hereditary condition. [2] Symptoms of gigantomastic may include mastalgia (breast pain), ulceration/infection, posture problems, back pain and chronic traction injury to 4th/5th/6th intercostal nerves with resultant loss of nipple sensation. It is may also associated with decreased fetal growth, if the gigantomastia is present during pregnancy. [1] Treatment is based on the person's symptoms and may include breast reduction, mastectomy with or without reconstruction, hormonal treatment, or a combination of treatments.[1][3]
Last updated: 6/29/2009


  1. Dancey A, Khan M, Dawson J, Peart F. Gigantomastia - a classification and review of the literature. J Plast Reconstr Aesthet Surg. December 13, 2007;
  2. Kulkarni D, Beechey-Newman N, Hamed H, Fentiman IS. Gigantomastia: A problem of local recurrence. The Breast. 2006;
  3. Antevski BM, Smilevski DA, Stojovski MZ, Filipovski VA, Banev SG. Extreme gigantomastia in pregnancy: case report and review of literature. Arch Gynecol Obstet. 2007;
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