Invasive micropapillary breast carcinoma: a retrospective study of classification by pathological parameters.

Micropapillary breast carcinoma has been recognized as a morphologically and biologically distinct form of breast carcinoma. Although data suggest that patient outcomes in cases of micropapillary breast carcinoma do not differ significantly from other breast carcinomas, the impact that a micropapillary component might have on the pathological work-up of a case of breast carcinoma remains an important point of discussion (especially as pertaining to the risk of lymphovascular disease). In this study, we perform an extensive retrospective study of the pathological parameters of seven years of breast surgical pathology cases to explore the relationship that micropapillary morphology might have with other important pathological parameters of a breast cancer case work-up (e.g. tumour size, lymphovascular invasion, lymph node status). We also analyze our data set to see if a micropapillary component would influence hierarchical classification by pathological parameters. Micropapillary features correlated with a higher frequency of ER positivity and lymphovascular invasion; there was no statistical difference between those cases with and without a micropapillary component from the perspective of other clinicopathological parameters, however. The presence of micropapillary features did influence classification, however, and produced a distinct cluster amidst comparison of other pathological variables.