Comparative Study of Robinson’s and Mouriquand’s Cytological Grading Systems and Correlation with Histological Grading in Breast Carcinoma

Abstract

Introduction: Fine Needle Aspiration Cytology (FNAC) plays a critical role in the initial evaluation and early diagnosis of breast masses, by providing relevant information on aggressiveness of tumour thus helping in the management. There is no gold standard for cytological grading due to lack of agreement among the pathologists and clinicians to accept them on par with Scarff-Bloom-Richardson (SBR) grading system. Aim: To study cytological grading by fine needle aspirate smears of breast carcinoma using Robinson’s grading and Mouriquand’s grading and to correlate with SBR histopathological grading on excised breast cancer specimens. Materials and Methods: This was a prospective study from March 2016 to August 2017, which included 75 cases of cytologically proven duct cell carcinoma of breast with their corresponding histopathology. They were graded cytologically by Robinson’s and Mouriquand’s methods and correlated histologically with SBR grading method. SPSS version 16.0 was used to calculate sensitivity, specificity and diagnostic accuracy. Concordance and discordance rates were measured by Kappa measurement of agreement. Results: Cases were divided into 3 grades both by Robinson’s and Mouriquand’s cytological grading methods. By Robinson’s method out of 75 cases, 10 cases (13.33%) were Grade I, 57cases (76%) were Grade II and 8 cases (10.66%) were Grade III. According to Mouriquand’s method cases were graded as Grade I-14 cases (18.66%), Grade II-54 cases (72%) and Grade III-7 cases (9.33%). As per histological grading done on surgical specimens according to SBR grading system, we found 23 (30.66%) were Grade I, 41(54.66%) were Grade II and 11 (14.66%) were Grade III. The concordance between the 2 cytological gradings was 85%. The concordance and discordance rates between Robinson’s cytological and Mouriquand’s grading with SBR histological grading was 78.6%, 66.6%, 21.4% and 33.4% respectively. The kappa values of agreement for Robinson’s and Mouriquand’s cytological gradings were k=0.100 (very good agreement) and k=0.118 (fair agreement) respectively. Conclusion: Cytological grading of breast carcinoma can be done by both Robinson’s and Mouriquand’s cytological grading with variable concordance with histological grading. However we observed Robinson’s cytological grading to be superior to Mouriquand’s cytological grading and hence can be preferred for routine cytological grading of breast carcinomas.

Keywords

• nuclear grading
• scarff-bloom-richardson grading
• triple diagnosis