[Early invasive mucinous carcinoma of the breast].

Cases of early invasive mucinous carcinoma of the breast have been reviewed. Microscopically, a typical lesion exhibits leakage of cancerous mucus into the stromal tissue from an intraductal carcinomatous component which were shown to be mucus-producing and to be lower papillary projection. Among 5,360 primary breast cancers that had been mastectomized at the C.I.H., 11 or 0.21% were determined as being "early" cases. All of these cases exhibited "pure type" mucinous carcinomas which were found to be highly mucus. The average age of these patients was 41 years (range: 34-51 yrs.), and no cases showed a nodal involvement. During an average follow-up of 8 years, no recurrent case were found. Thus, we have found that these "early" cases revealed an early invasion of a mucinous carcinoma that is highly mucus-producing but without an invasive ductal carcinomatous pattern.