Sarcoma of breast, with particular reference to its origin from fibroadenoma.

Thirty-nine sarcomas of breast are described. The patients' ages ranged from 26 to 78 years but most patients were middle-aged or elderly. Evidence is adduced that 16 of the tumours arose from pre-existing fibroadenomas and others very probably did so. Many tumours were adenosarcomas and one was a carcinosarcoma which preserved its structure in a lymph-node metastasis. Recurrences were mostly local, but a small group had a much graver prognosis. A pleomorphic and giant-cell structure usually meant a high degree of malignancy but the significance of cartilaginous or bony metaplasia, present in seven tumours, was less certain. It is wise to regard all ;fibroadenomas' of the breast occurring in patients over 40 years of age as at least potentially malignant, and these should be examined histologically with care, particularly since sarcomatous change may be present in one part only and therefore easily overlooked.