A comparison of the metastatic pattern of infiltrating lobular carcinoma and infiltrating duct carcinoma of the breast.

The metastatic sites of infiltrating duct (IDC) and infiltrating lobular carcinoma (ILC) have been compared using both clinical and autopsy data. The following statistically significant differences were found: Lung parenchymal metastases were more common in IDC. Bone trephine biopsies were more likely to be positive in ILC. Carcinomatous meningitis was associated almost exclusively with ILC. Peritoneal/retroperitoneal metastases of distinctive pattern occurred in ILC. There was often associated linitis plastica-like involvement of the stomach wall and diffuse infiltration of the uterus. Hydronephrosis was a common secondary phenomenon.