The diagnostic utility of cell block in fine needle aspiration cytology of palpable breast lesions in a Nigerian tertiary health institution.

Background: Although fine needle aspiration cytology (FNAC) is highly accurate for detecting breast malignancies, concerns remain among cytopathologists about false-positive and false-negative diagnoses. Cell block (CB) preparations have been advocated by some cytopathologists as one of the methods to improve and consolidate the diagnostic accuracy of FNAC. The aim of this study was to determine the diagnostic utility of CB in FNAC of palpable breast lesions among female patients.

Methods: Following FNA, CBs were prepared using 10% neutral-buffered formalin from the residual breast aspirates of 100 consecutive female patients attending the FNAC clinic. The slides of the conventional smears, CB and excisional biopsies were examined, and results were analysed using the SPSS.

Results: Of the 100 patients that had FNAC, 44 (44%) had excisional biopsy performed. An additional 13% diagnostic yield for malignancy was obtained with the use of CB preparations. CB reduced equivocal diagnoses by 25%, corresponding with 90.9% improvement on definitive diagnoses.

Conclusion: In our setting, the addition of CB to smear remarkably improved the diagnostic utility of breast FNAC by minimising atypical and suspicious for malignancy diagnostic categories.