Résumé
Lobular neoplasia is the new WHO terminology that encompasses the so-called lobular carcinoma in situ and atypical lobular hyperplasia. Besides the classical forms, particular variants have been described, which are mammographically detectable with distinct histologic patterns and behaviour. These variants are characterized by pleomorphic cells, necrosis with calcifications and may be associated to an invasive lobular carcinoma. Their clinical issue looks more like a preinvasive lesion than a marker of increased risk. Thus, their identification on biopsy requires a surgical reexcision. Hybrid forms, sharing a mixed lobular and ductal morphology and phenotype, have also been mentionned. Despite a lack of prognostic evaluation, it seems logical to recommend a subsequent surgical investigation when they are observed. Classical forms are usually managed by simple follow-up, although this attitude does not make a consensus among pathologists. Lobular neoplasia are not all indolent lesions and belong to an heterogeneous group that percutaneous guided biopsies have emphasized. They should be managed in a pluridisciplinar way and correctly diagnosed on percutaneous biopsies as well as surgical specimens.