Malignant Rhabdoid Tumor of the Breast: A Case Report

A 66-year-old woman developed a malignant rhabdoid tumor of the breast, with a tumor doubling time of 10 days. One month after radical mastectomy, there was local recurrence, followed by multiple pulmonary metastases, and the patient died of respiratory failure 5 months after surgery. The gray-white-colored tumor measured 13 x 12 x 10 cm, and its border was well defined. The tumor was composed of diffusely growing round or polygonal cells with vesicular nuclei, prominent nucleoli, and ample cytoplasm containing eosinophilic inclusions. Lymph node involvement was widespread. Both vimentin and keratin were clearly demonstrated by immunohistochemical staining. Ultrastructural studies revealed that the MRT cells contained cytoplasmic whorls of intermediate filaments.