Atypical ductal hyperplasia

A high-risk benign lesion found in approximately 10% of benign breast biopsies.

Refers to the proliferation of dysplastic epithelial cell populations, that include clonal populations.

A transitional zone between benign and malignant disease and is considered premalignant.

Found on a stereotaxic core biopsy of the breast warrants surgical excision because over 50% of these lesions have a carcinoma at the time of excision.

Characterized by filling and distension of the involved ducts by epithelial cells which are monotonous forming complex architecturally patterns including crib inform like secondary lumens or micro papillary formations.

Atypical lobular hyperplasia has expanded acini of the lobular unit which is filled with small monotonous, round, or polygonal cells with a lack of cohesion and loss,of acinar lumens.

Atypical lobular hyperplasia, lobular ca-in situ and invasive lobular carcinoma have reduced or absent expression of cell-cell protein junction E-Catherine.

97% of atypical ductal hyperplasia lesions and 88% of atypical lobular hyperplasia lesions have ER positive staining in 10% or more of cells.

Lobular carcinoma-in-situ is similar to atypical lobular hyperplasia histologically but is more extensive and has a higher risk of breast cancer, relative risk of 8-10.

DCIS similar to atypical hyperplasia but is more extensive and has a relative risk of 8-10 for development of breast cancer.

Atypical ductal hyperplasia is a risk factor for breast cancer and the projected cumulative incidence of breast cancer, both invasive and ductal carcinoma in situ after diagnosis was 29% over 25 years (Hartmann LC).

Atypical ductal hyperplasia today is most often diagnosed by needle biopsy of an imaging finding rather than by excisional biopsy.

The risk of breast cancer associated with atypical ductal hyperplasia diagnosed by needle biopsy appears to be lower than that reported based on historical controls by excisional biopsy.

Multiple studies suggest a four fold increased of breast cancer.

Cumulative incidence of breast cancer approaches 30% at 25 years of follow-up.

The younger the age at the time of diagnosis of atypical hyperplasia the higher the risk for the development of breast cancer.

Suggested to be associated with an absolute risk of 1% per year of developing breast

10-20% risk of subsequent cancer and a 3:1 ratio of ipsilateral to contralateral breast.

Mayo Benign Breast Disease Cohort based on 331 women with atypical hyperplasia found that a positive family history for breast cancer did not increase further the risk of its development in such patients.

Mayo Benign Breast Disease Cohort based on 331 women with atypical hyperplasia found that the presence of multiple foci of atypia and the presence of calcifications indicted very high risk for patients to develop breast cancer, that is, >50% at 20 years.

Two types of atypical hyperplasia: atypical ductal hyperplasia and atypical lobular hyperplasia.

The two types are equal in frequency with equal risks for the development of breast cancer.

The relationship with atypical hyperplasia and a family history of breast cancer remains controversial, but it is likely that atypical hyperplasia is a phenotype that reflects the risk inherent in a family history.

Atypical ductal hyperplasia confers a future risk of breast cancer to either breast of approximately 1% to 2% per year or approximately 25% to 30% at 25 years of follow-up: benefit of ET is imperative in this population.

The greater number of foci of atypical hyperplasia the greater the risk of breast cancer, and the greater the degree of involution of background lobular units the lower the risk.

Among women with atypical ductal hyperplasia from which cancer develops approximately 78% are ductal, and 22% are lobular or other histologic types.

In patients with atypical lobular hyperplasia in whom cancer develops, 77% of cancers are ductal and 23% are lobular or of the histologic types.

Among patients with atypical hyperplasia who developinvasive breast cancer 75% have node negative disease, and 25% node positive cancer, with 88% estrogen receptor positivity.

For adequate diagnosis surgical excision at the site of atypical hyperplasia needle biopsy is recommended to decrease the chance of a missed malignancy.

By biopsing tssue with surgical excision up to 15-30% of the time a malignancy can be identified.

Excisional biopsy is the current standard when atypical ductal hyperplasia is identified by core biopsy.

With atypical lobular hyperplasia the rates of upgrading to a diagnosis of cancer range from 0-67% when excisional biopsy is performed.

The usefulness of MRI screening In patients with atypical hyperplasia it is still in question.

In randomized clinical trials using selective estrogen-receptor modulators (SERMs) and aromatase inhibitorrs for the prevention of breast cancer showed an 38% relative reduction in the risk of breast cancer, invasive and noninvasive, among all study participants and in the atypical hyperplasia group it was a reduction of 41-79%.

Tamoxifen provides an 86% reduction in breast cancer risk with 5 years of treatment.

The Breast Cancer Prevention Trial showed a 75% reduction in the occurrence of invasive breast cancer in patients treated with tamoxifen.

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