Lobular carcinoma of the breast: an overview.

The biologic nature, diagnostic features and therapeutic management of patients with lobular carcinoma in its in situ and invasive forms are discussed. Although recorded studies emphasize that patients with lobular carcinoma in situ are "at risk" for the development of invasive cancer, it has not been unequivocally demonstrated whether such an event represents a persistence of cancer due to inadequate excision or a de novo lesion. In support of the latter is the contention that lobular carcinoma exhibits a propensity for multicentricity and bilaterality. The recognition that the histologic types of the subsequent invasive cancers are not universally lobular invasive might also be cited in this regard. This information also bears upon views purporting a stepwise development of lobular invasive carcinoma from its in situ analog. Analysis of our own material fails to confirm any significant association between invasive lobular carcinoma and multicentric lesions. The diagnostic difficulty in distinguishing lobular hyperplasia from in situ lobular carcinoma and the inadvisability of frozen sections for this purpose is noted. Although the results of some electron microscopic studies of the in situ lesion challenge the propriety of its "pure in situ" nature; this criticism does not appear valid from both a pathological as well as pragmatic standpoints. The various schemes have been proposed concerning the surgical management of patients with lobular carcinoma in situ are presented and discussed. Certain biologic principles prompt consideration of segmental mastectomy and axillary node sampling as an alternative, commodious form of treatment for such lesions. There does not appear to be any unique reason to invoke any different treatment regimen for lobular invasive carcinoma than has been utilized for other invasive breast cancers.