Jun 5, 2008

Fibroadenoma





Fibroadenomas are benign tumors that represent a hyperplastic or proliferative process in a single terminal ductal unit; their development is considered to be an aberration of normal development. The cause of these tumors is unknown. Approximately 10% of fibroadenomas disappear spontaneously each year, and most stop growing after they reach 2-3 cm.

Fibroadenomas may involute in postmenopausal women, and coarse calcifications may develop. Conversely, fibroadenomas may grow rapidly during pregnancy, during hormone replacement therapy, or during immunosuppression, in which case they can simulate malignancy. In immunosuppressed patients, the etiology of multiple or growing fibroadenomas appears to be related to Epstein-Barr virus infection.

On clinical examination, fibroadenomas are oval, freely mobile, rubbery masses that may be nonpalpable or palpable. Their size varies from smaller than 1 cm in diameter to as large as 15 cm in diameter in the giant forms. Most commonly, the tumors are removed surgically when they are 2-4 cm in diameter. In young women, the tumors are usually palpable. In older women, the tumors typically appear as a mass on mammograms and may be palpable or nonpalpable.

In approximately 50% of women who receive cyclosporine after renal transplantation, fibroadenomas develop, and these tumors are often multiple and bilateral. The size of fibroadenomas also can vary during the menstrual cycle and during pregnancy. During postmenopause, tumors regress and often develop calcifications. Cancer may arise in a fibroadenoma, occurring in about 2.9% of cases; an increase in size, a change or irregularity in the margin, the development of small pleomorphic calcifications, and the presence of cystic spaces all suggest a developing malignancy.

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