Cytology of indeterminate cases (C3). Can this diagnostic class be improved?

The aim of this brief report is to emphasize the need for a stronger effort from Pathologists, to reduce the incidence of the "C3", Indeterminate, diagnostic class. The experience derived from immunohistochemistry could be useful also when applied to cytological samples. In this study, based on immunostaining for HMW Cytokeratin 5 (normally present in normal breast cells and absent in malignant cells) on conventional breast nodules aspirates, 21 out of 30 evaluated cases diagnosed as "C3" and with histological control, have been reclassified as "C2", Benign or "C4", Suspicious of malignancy. The Authors conclude that this immunocytochemical algorithm could emprove the diagnosis di "C2" and "C4", avoiding in many cases other presurgical, more invasive diagnostic procedures, with a positive cost/ benefit ratio.