Representative cytological findings of invasive ductal carcinoma, scirrhous growing type (SIDC). The cells form small clusters with little atypia on cytological specimens, which hinders attempts to differentiate between benign and malignant cases. This often results in the classification of these cases as indeterminate and/or false-negative. Cases of SIDC are sometimes classified as inadequate when too few cells are collected for evaluation, especially for tumors rich in fibrous components, as these are difficult to sample .
Yamaguchi et al. Diagnostic Pathology 2012 7:53 doi:10.1186/1746-1596-7-53