FINE-NEEDLE ASPIRATION DIAGNOSIS OF RENAL ONCOCYTOMA - A MATHEMATICALMORPHOLOGIC APPROACH

Differentiation between renal oncocytomas and well-differentiated oxyp hilic cell renal carcinomas from fine needle aspiration cytology smear s may present considerable difficulties. To better define diagnostic c riteria, we used high-resolution architectural characteristics of nucl eus and cytoplasm based on mathematical morphologic concepts. Particul ate structural elements were selected for their size and optical densi ty by the so-called top-hat function. Spatial density, size distributi on and a function of distance between particles were computed. We quan titated cellular samples from fine needle aspirates obtained from 10 r enal oncocytomas and 5 well-differentiated oxyphilic cell renal carcin omas. In two of the former, cytologic diagnosis was doubtful. Subseque nt removal of the tumor and its histologic examination established the final diagnosis in all cases. Stepwise discriminant analysis correctl y classified all cases as oncocytomas or renal carcinomas, although th e results need to be considered with caution due to the necessarily li mited number of observations. Multivariate graphic representation by s tar glyphs clearly depicted the differences between oncocytoma and oxy philic cell renal carcinomas and the abnormal characteristics of two o ncocytoma cases misclassified initially.