Predominant fatty variant of myofibroblastoma of breast.

Myofibroblastoma of the breast is an uncommon but well defined benign stromal tumour. This report describes a case in which the predominant histological component was mature adipose tissue and two further cases with a major adipocytic component. Although small foci of adipose tissue are a recognised feature of this tumour, the dominance of the histological pattern by fat has not been described previously, and the recognition of this variant is important to allow confident diagnosis and avoid confusion with other primary adipocytic or stromal lesions, especially in the setting of potential needle core biopsy of such a lesion.