[Rare breast tumors]

Rare breast tumors include benign or borderline entities that are often clinically and radiologically misleading. Diagnosis relies in all cases on appropriate biopsy and cross-anatomical-radiological interpretation. Optimal management requires multidisciplinary discussion. Desmoid tumors are non-metastatic but locally aggressive, infiltrative fibroblastic lesions whose management is now based on active surveillance. Idiopathic granulomatous mastitis is a chronic inflammatory mastitis, probably of autoimmune origin, which generally responds to corticosteroid treatment. Phyllodes tumor is a rare fibro-epithelial proliferation, with variable behavior depending on its histological grade, requiring complete excision with negative margins. Radial scarring, a benign sclerosing lesion, can mimic a carcinoma, and sometimes warrants excision depending on the presence of atypia. The aim in managing all these rare tumors is to limit overtreatment, while ensuring personalized follow-up.