Metastatic breast carcinoma identified in a uterine leiomyosarcoma

A rare example is described of an advanced invasive ductal carcinoma of the breast with concomitant metastatic foci in a uterine leiomyosarcoma. Both tumors arose in a 48-year-old woman, without any evidence of distant metastases as assessed on imaging at the time of diagnosis. The double diagnosis in this particular case was established on a combination of microscopic appearance of the uterine tumors in the hysterectomy specimen, immunophenotype assessment, and clinical information on the breast carcinoma. But the association between the two malignancies can be challenging and potentially difficult to prove.