Two unusual examples of secondary tumors arising in adenolipomas were diagnosed in a 16-year-old girl and a 27-year-old woman, each of whom presented with asymmetric enlargement of the right breast. In both instances, a significant secondary lesion was associated with the adenolipoma. In the first case, a cyst appeared to have arisen in a fibroadenoma within the adenolipoma, which had apparently undergone infarction during a recent pregnancy and postpartum period. There was micropapillary duct epithelial hyperplasia of the cyst lining epithelium. In the second case, an adenofibroma with atypical lobular hyperplasia was present within the adenolipoma.