[Fibromatosis of the breast].

Fibromatosis of the breast is a rare benign mesenchymal transformation of the connective tissue, the origin of which is probably situated in the fascia of the pectoral muscle and the Cooper's ligaments. In the clinical and radiological examination, it is difficult to differentiate between a mammary carcinoma or other malignant tumours of the breast. Only histological examination can lead to the final diagnosis. Large-scale excision of these tumours, which have a tendency to relapse, is the therapy of choice. The diagnostic problems are shown in a case of a 26-year old patient.