Mammographic appearance of nonpalpable breast cancer reflects pathologic characteristics.

Objective: To study the relationship of mammographic appearance of nonpalpable breast cancer to the pathologic characteristics.

Summary Background Data: The mammographic appearance of nonpalpable breast cancer may be associated with pathologic variables having prognostic significance, which could influence clinical management.

Methods: The authors correlated the mammographic appearance and pathologic characteristics of 543 nonpalpable malignancies diagnosed in a single institution between July 1993 and July 1999. Cancers were divided into four groups based on mammographic presentation: mass, calcification, mass with calcification, and architectural distortion.

Results: The majority of masses (95%), masses with calcifications (68%), and architectural distortions (79%) were due to invasive cancers, whereas the majority of calcifications (68%) were due to ductal carcinoma in situ (DCIS). Among invasive cancers, calcifications were associated with more extensive intraductal carcinoma, more Her2/neu immunoreactivity, and more necrosis of DCIS. Lymphatic invasion was more common in cancers presenting as a mass with calcifications. Sixty-nine percent of DCIS associated with invasive cancers presenting as calcifications were of high grade according to the European Organization for Research and Treatment of Cancer. Calcifications in noninvasive tumors were associated with necrosis in DCIS. Two thirds of cancers presenting as architectural distortion had positive margins (65%) compared with 35% to 37% of other mammographic presentations. Mammographic presentation was not significantly related to tumor differentiation or estrogen or progesterone receptor status. The ratio of invasive to noninvasive malignancies increased progressively with increasing age from 1:1 in patients younger than 50 years of age to 3:1 in patients older than 70 years, whereas the proportion presenting as calcifications declined from 63% in patients younger than 50 years to 26% in patients older than 70 years.

Conclusions: Malignancies presenting as calcifications on mammography are most commonly DCIS. When invasive malignancies presented as calcifications, the calcifications were associated with accompanying high-grade DCIS, and the invasive cancers were often Her2/Neu positive. Mammographic masses with calcifications were associated with lymphatic invasion. Excisional biopsy margins were most commonly positive with architectural distortions. The mammographic appearance of nonpalpable malignancies is related to pathologic characteristics with prognostic value, which varies with patient age and influences clinical management.