Comparison of Diagnostic Fine-Needle Aspiration of Breast Masses Obtained from Cell Blocks and Conventional Smear Methods Using Prognostic/Predictive Biomarkers for Confirmation

ABSTRACT

Background: Fine-needle aspiration cytology (FNAC), a rapid, minimally invasive technique has been extensively used as the first-line diagnosis of breast lesions. However, sometimes its yield is not adequate for precise diagnosis and the risk of false-negative and indeterminate diagnosis is always present. Objectives: The aim of this study is to compare the diagnostic results of fine needle aspiration cytology (FNAC) of breast mass samples obtained from cell blocks (CB) and smears (CS), using ER, PR, and HER2/neu as objective tumour makers for confirmation. Method: Smears were made from breast aspirates collected from 150 consenting female participants at the FNAC clinic of the Department of Anatomic and Molecular Pathology, Lagos University Teaching Hospital (LUTH), using the conventional smear method. A modified cell block (CB) preparation was also prepared using 10% Neutral Buffered Formalin (NBF) Both smears and sections from the cell block preparations were stained in haematoxylin and 1% aqueous eosin stain and demonstrated for estrogen (ER), progesterone (PR) and human epidermal receptor 2 (HER2) tumour markers using standard immunocytochemical (ICC) methods. A comparison was then made of the final diagnosis of both methods. Results: The CS method showed 6(4%) of the participants were C₅ malignant, 3(2%) were C₄ suspicious for malignancy, 114(76%) C₂ benign lesion, 6(4%) had blood/mucus exudates 15(10%) inadequate smears and were C₁ unsatisfactory, while the remaining 6(4%) had acellular smears. However, the cell block (CB) method showed that 15(10%) of the participants had inadequate cells C₁ unsatisfactory, 6(4%) were inflammatory C₁, 114(74) were C₂ benign, 9(6%) were suspicious/benign, while the remaining 9(6%) were malignant as against 6(4%) of the conventional smear. The IHC method carried out on the additional 3(2%) yield from the cell block method using ER, PR, and HER2/neu antibodies revealed that 1participant was ER, PR, and HER2/neu Positive, while the other 2 were negative for the 3 antibodies used. Conclusion: Cell block method with biomarker gave better architectural patterns, high cellularity, morphological features and an additional yield of malignant cells than the smear method