What causes small, peripheral intraductal papilloma (IDP)?

Updated: Dec 25, 2019
  • Author: Joshua I Warrick, MD; Chief Editor: Chandandeep Nagi, MD  more...
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Risk factors for breast tumors include use of contraceptive and/or hormone replacement therapy, lifetime estrogen exposure, and family history. [2]

Relatively recent molecular evidence has shown that papillomas frequently have loss of heterozygosity (LOH) at loci on chromosome 16. Specifically, Di Cristofano et al found LOH at telomeric 16p (marker D16S423) in 3 of 11 informative papillomas, as well as at centromeric 16q (marker D16S310) in 1 of 3 informative papillomas. [10] Similarly, Lininger et al found LOH at 16p13 in 6 of 10 informative intraductal papillomas with florid epithelial hyperplasia. [11]

Extensive studies of usual ductal hyperplasia (UDH) have shown it to have frequent, although inconsistent, chromosomal imbalances, and it has become suggested that UDH is a truly neoplastic process. [12] Given that allelic imbalances are also characteristic of breast papillomas, as preliminary studies indicate, it is likely they are also truly neoplastic. It should be recognized, however, that these studies did not distinguish between small, peripheral intraductal papilloma (IDP [S/P ST]) and large, central intraductal papilloma (IDP [L/C ST]), and that genetic difference may exist between these lesions.

In addition, IDP (S/P ST) is frequently present in breasts involved by other benign proliferative lesions, including columnar cell hyperplasia (CCH), sclerosing adenosis, and usual ductal hyperplasia (UDH). Therefore, it stands to reason these breasts are somehow the "fertile soil" from which proliferative lesions of all types arise. However, what makes this "fertile soil" is an enormous question that remains unanswered.

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