Clinicopathologic and Immunophenotypic Classification of Invasive Lobular Carcinoma with Histiocytoid Features.

Histiocytoid lobular breast carcinoma is a morphologic variant of lobular carcinoma with apocrine features that shows a variable immunohistochemical profile and variable clinical behavior. Further subclassification and stricter diagnostic criteria may be helpful in the distinction between truly indolent tumors and those with more aggressive clinical features.