Two obese women with thrombotic disease complicated by necrosis of the breast are described. In one patient the reaction started after a few days of coumarin treatment and progressed to severe necrosis requiring mastectomy. The other patient was not on anticoagulant therapy when the breast reaction started and the clinical course was less severe. The radiographic appearance was characterized by thickening of the breast trabeculae, increased density of the breast and skin thickening. Although the radiographic findings are non-specific, the correct diagnosis can be suggested if combined with appropriate clinical information. The disease process may mimic breast cancer of the inflammatory type, clinically as well as radiographically.