[Differential diagnosis of spindle cell tumors of the breast from biopsy material]

Spindle cell proliferations are a rare but diagnostically challenging finding in breast biopsy material. The spectrum of possible diagnoses ranges from benign lesions, such as hamartomas, myofibroblastomas and biphasic tumors, such as adenomyoepitheliomas to malignant lesions, such as metaplastic carcinomas, phyllodes tumors and genuine sarcomas. A correct diagnosis from the preoperative biopsy material helps prevent inappropriate therapy and overtreatment or undertreatment. In this review five morphological patterns of spindle cell tumors of the breast and the most important representatives in this group are discussed.