Mixed metaplastic carcinoma of the breast associated with pregnancy: Diagnostic dilemmas in fine-needle aspiration cytology

Metaplastic carcinoma of the breast represents a rare entity characterized by the simultaneous presence of ductal, squamous, and/or mesenchymal components in several proportions. There are limitations in fine‐needle aspiration diagnosis due to its pathological heterogeneity. When it develops under pregnancy and lactation influence, the cytologic evaluation appears to be more difficult and accurate diagnosis often proves challenging. We describe a case of mixed metaplastic carcinoma with dominant areas of squamous metaplasia, sarcomatoid stroma with spindle cells, and a minor component of cartilaginous metaplasia. We notify our experience in diagnostic approach of this entity focusing on differential diagnosis. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.