Purpose: Fine needle aspiration cytology (FNAC) is a diagnostic method characterized by high sensitivity, specificity and predictive value. In order to obtain uniformed results of FNAC breast changes, the following categories are introduced: C1 (non-representative), C2 (benign), C3 (atypical), C4 (suspected) and C5 (malignant). The purpose of this study was to establish which pathological processes are most frequently diagnosed as C3 and C4 categories, which carry a malignant tumor risk.
Methods: The frequency of all cytological categories was determined in a retrospective analysis which included 1605 patients, all of whom had undergone FNAC of breast lesions, over a period of 5 years (2012-2016). Furthermore, histopathological diagnoses of 212 patients with cytological categories C3 (77) or C4 (135) were compared.
Results: In the sample of 1605 patients, 212 belonged to C3 or C4 cytological category ( frequency for C3 4.8%, for C4 8.4%). Also, in the group of patients with cytological categories C3 and C4 there were 208 women. The patients with C3 were younger than C4 patients. There was a statistically significant difference between the number of benign and malignant diagnoses in patients diagnosed with C3 or C4 cytological category (p<0.001). In C3 category, in 57.1% of the cases a benign condition was histopathologically diagnosed, while in C4 category, in 90.4% of the cases malignant tumor was histopathologically diagnosed.
Conclusions: After histopathological analysis, C3 category in FNAC breast lesions is most commonly diagnosed as a fibrocystic breast disease or fibroadenoma, while C4 category is diagnosed as well-differentiated malignant tumor.