Abstract

Invasive micropapillary carcinoma (IMPCa) is a rare variant of invasive ductal carcinoma of the breast. This variant is associated with a set of peculiar cytological findings and aggressive biological behaviors. In most reported cases, IMPCa has involved massive axillary lymph node metastases at the time of diagnosis. We experienced four cases of cytological features of IMPCa, all of which were verified by histological examination. Fine needle aspiration cytology (FNAC) revealed malignant epithelial cells, which formed small, oval to angulated papillary clusters, which lacked central fibrovascular cores. The histological findings of the four cases revealed both pure and mixed forms of IMPCa, composed of cohesive malignant epithelial cells, surrounded by distinctive clear spaces and separated by thin fibrous septa. All patients evidenced axillary lymph node metastases at the time of diagnosis. It is important to identify the peculiar cytological findings which would differentiate IMPCa from other diseases.

• Keywords: Breast;Invasive micropapillary carcinoma;Fine needle aspiration cytology;