In general, lesions of lobular neoplasia are incidental findings detected when a biopsy is being performed to evaluate some other pattern of fibrocystic or malignant breast disease. The absence of any gross clinical or mammographic features specifically associated with these entities creates difficulty in accurately quantifying incidence. Table 25.1 demonstrates the relatively low prevalence (0.5% to 4.3%) of LCIS based on retrospective reviews of benign breast biopsies (3,4,6,26,27,28,29,30,31,33,34,35,36,37,38). Prevalence rates are higher when cancerous biopsies are included. Incidental detection rates of LCIS are also higher (4% to 25%) in two studies reporting the pathologic findings in prophylactic mastectomy specimens from high-risk women (34,35). Autopsy setudies have a potential age bias in favor of older cases in series of natural cause deaths, or favoring younger age in forensic series (34,35). Kauff et al. (34) described findings in a forensic autopsy series of 490 nonpregnant women, 76% of whom were younger than 55 years of age, and found only 2 cases (0.4%) each of LCIS and ALH. A review by Frykberg (35) of 19 published series (1989 to 1999) involving biopsy results for 10,499 nonpalpable, mammographically detected breast abnormalities revealed LCIS identified in 1.1% of all cases and in 5.7% of those cases where a malignancy was diagnosed.

Table 25.1. Detection Of Lobular Neoplasia: Incidence And Prevalence Rates

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