Supplementary Material for: Cytomorphological assessment in aspirates of ductal carcinoma-in-situ – correlations with histopathologic grade, architectural pattern, and invasion

Introduction
Fine-needle aspiration biopsy (FNAB) of the breast is an effective and widely adopted diagnostic technique. Histopathologic grading of ductal carcinoma-in-situ (DCIS) has prognostic significance. In this current study, FNAB of DCIS were reviewed to identify parameters that predict grading, histopathologic architecture, and presence of invasion in DCIS.

Methods
Aspirates from histopathology-proven cases of DCIS were retrieved and reviewed for cytomorphologic parameters including cellularity, composition, epithelial fragment architecture cellular/nuclear features.

Results
In total 104 aspirates were reviewed. Cytopathologic cellular features – large nuclear size (p = 0.005), prominent nucleoli (p = 0.011), increased nuclear membrane irregularity (p = 0.043), high variation in nuclear size (p = 0.025), and presence of apoptotic figures in epithelial structures (p < 0.001); and background debris (p = 0.033) correlated with a high-grade diagnosis. Cytoplasmic vacuolation (p = 0.034) was seen exclusively in non-high-grade aspirates. Epithelial fragment architecture did not correlate with grading. A predominance (≥ 50%) of solid aggregates and papillary fragments on FNAB correlated with histopathologically solid (p = 0.039, p = 0.005) and papillary (p = 0.029, < p = 0.001) patterns. No parameter showed correlation with invasion.

Conclusion
FNAB is effective in predicting DCIS grading. Epithelial fragment architecture assessment is limited to papillary or solid-types, and FNAB cannot predict focal invasion in DCIS.