[Lobular carcinoma in situ of the breast].

The diagnosis of the lobular carcinoma in situ (LCIS), whose frequency is estimated to range from 0.8 to 3.8 p. cent of breast cancers on the whole, is exclusively anatomopathological since it does not have any specific clinical and/or radiological characteristics. After describing the two main differential diagnoses, the various possible treatments are studied, bearing in mind that the therapeutic strategy must take into account the three characteristics which are typical of LCIS: multicentricity, bilaterality and the possible occurrence of an invasive cancer.