[Tumor and tumor-like benign mesenchymal lesions of the breast]

All the spectrum is encompassed of those miscellaneous pathologic entities occurring in the mammary stroma which are on record up to date other than "mixed fibroepithelial" tumors (fibroadenomas and phyllodes tumors) and tumors both "pure" and "mixed" originating from myoepithelium (adenomyoepitheliomas and pleomorphic adenomas). Also they were excluded those dysreactive-autoimmune diseases (sarcoidosis, sclerosing lymphocytic lobulitis, lobular granulomatous mastitis) and those inflammatory-infectious conditions (tuberculosis, actinomycosis, foreign body reactions, Mondor's disease) which can mimick breast tumors clinically or on image analysis, but on the contrary not evoking the idea of a tumor on histology. Specifically, inflammatory pseudotumor, myofibroblastoma, leiomyoma, neurinoma/neurofibroma, benign fibrous histiocytoma, hemangiopericytoma, fibromatosis, nodular fascitis, variants of lipoma, mesenchymoma, amartoma and its variants, hemangiomas, pseudoangiomatous hyperplasia of stroma, amyloid tumor, granular cell tumor, are consecutively described and discussed, with a large list of references enclosed to each rubric. Most of the pictures are taken from personally observed lesions of the breast. Only few pictures referred to are from their analogue lesions which occurred in soft parts of other locations, with specific mention of that when it was the case. Of note after reviewing the literature the fact that no glomus tumor, nor Kaposi's sarcoma either sporadic or in the context of any immunodeficiency, nor myelolipoma has been recorded yet.