Parotid gland tumors: Correlation between routine cytology and cytomorphometry by digital image analysis using conventional and newly introduced cytomorphometric parameters

The objective of this study was to compare qualitative cytomorphology and morphometric characteristics of parotid gland tumor cells, with the aid of a computer-assisted system of image analysis. Routine qualitative cytologic and quantitative morphometric results from 64 parotid gland tumors were compared. Ultrasound (US)-guided fine-needle aspiration (FNA) specimens were taken from 54 patients. Eleven conventionally used morphometric parameters were studied: area, perimeter, convex area, convexity, maximal and minimal radius, length, breadth, form factor (FF), elongation factor, and nuclear- cytoplasmatic (N/C) ratio. Two newly introduced nuclear form factors were also measured: area symmetry factor and perimeter symmetry factor. The following nuclear morphometric parameters were significantly different between malignant and benign tumors: area, perimeter, convex area, convexity, maximal and minimal radius, length, breadth, FF, elongation factor, area symmetry factor, and perimeter symmetry factor. Comparing the cutoff values and receiver operating characteristic (ROC) curves the following nuclear morphometric parameters were found most useful in separating benign from malignant tumors: area, perimeter, convex area, maximal radius, length, and FF. The following whole cell morphometric parameters were significantly different between malignant and benign tumors: minimal and maximal radius, convexity, breadth, FF, and elongation factor. N/C ratio was significantly higher in malignant tumors. The quantitative morphometric analysis is a useful tool in the cytological differentiation between benign and malignant parotid gland tumors. Computerized image analysis may add to morphological evaluation by turning qualitative data into quantitative values. Diagn. Cytopathol. 2013;41:776-784. (c) 2013 Wiley Periodicals, Inc.