Correlation of histologic grade of breast carcinoma with cytologic features on fine-needle aspiration of the breast.

Histologic grade is an important prognostic factor for breast carcinoma. To determine whether histologic grade could be reproduced on fine-needle aspiration of the breast, we analyzed 50 cases of histologically proven infiltrating ductal carcinomas that had a preoperative fine-needle aspiration. The histologic grade was based on tubule formation, nuclear pleomorphism, and mitotic frequency [a modified Bloom-Richardson (BR) grading system]. Fine-needle aspirations were analyzed for cellularity, cellular arrangements, percentage of single cells, nuclear pleomorphism, mitoses, hyperchromasia, chromatin pattern, nucleoli, and background. The cases in BR Grades 1 and 2 (n = 28) were combined into one category for comparison with those in BR 3 (n = 22). BR 3 was more likely than BR 1 and 2 to be associated with marked nuclear pleomorphism (59 versus 18%, P < 0.05) and vesicular or coarse chromatin (77 versus 43%, P < 0.05). Of the 18 cases that showed both marked nuclear pleomorphism and either coarsely granular or vesicular chromatin on fine-needle aspiration, 13 (72%) were BR Grade 3 on histology. These 13 cases represent 59% of the 22 cases of BR Grade 3 on histology. Aspiration cytology is of some, but limited, use in predicting BR grade. As expected, nuclear features are most easily translated from histology to cytology.