Cytomorphometry as quality control for fine needle aspiration. A study in 321 breast lesions.

Material collected by fine needle aspiration (FNA) in 321 histologically examined primary breast lesions of previously untreated patients was analyzed by morphometry. The mean nuclear area (MNA) and its standard deviation (SD) were calculated for 50 cells in each case. Four subclasses were defined on the basis of the MNA and SD: benign (less than 10% probability of malignancy), doubtful benign (10% to 49%), doubtful malignant (50% to 90%) and malignant (greater than 90% probability of malignancy). FNA samples showing signs of acute inflammation or only apocrine metaplastic cells were not suitable for analysis by this morphometric method and were excluded. In 274 (85.4%) of the cases, the measurements allowed a definite morphometric conclusion, with predictive values of 99.5% and 100% for the histologically malignant and benign aspirates, respectively. The probability of malignancy in the doubtful malignant group was almost 86%. The morphometric method described is quick, easy to perform and well suited for use in routine daily practice; furthermore, it does not require expensive equipment. The ease of the technique and its high predictive value make this method appropriate for use as a quality control procedure in FNA cytology.