DNA image cytometric analysis of paraffin‐embedded sections of small renal cortical neoplasms

DNA ploidy analysis of neoplasms is most frequently performed by flow cytometry of single nuclear suspensions or image analysis of Feulgen-stained cytologic specimens. To assess the prognostic significance of ploidy in renal adenomas (less than 3 cm in diameter), nuclear DNA content of 21 renal cortical neoplasms was analyzed by image cytometry (CAS 200, Cell Analysis Systems, Inc., Elmhurst, IL) on Feulgen-stained 5 microns fixed embedded tissue sections. Five (36%) of 14 small neoplasms (so-called renal adenomas; (mean diameter, 7.2 mm; range, 2-24 mm) were in the aneuploid range. Four (57%) of seven carcinomas (mean diameter, 6.3 cm; range, 3.5-10 cm) were aneuploid, a frequency not significantly different from that in the adenomas (P = 0.4). Mean DNA index (1.38) for aneuploid adenomas and carcinomas was identical. Diploid renal adenomas (mean diameter, 5.9 mm) were smaller, although not significantly so (P > 0.05), than the aneuploid ones (mean, 9.7 mm). Size of diploid (mean, 6.7 cm) and aneuploid (mean, 6.1 cm) renal carcinomas was similar. Clinical follow-up studies to evaluate utility of DNA ploidy and proliferative activity in prognosis and management of small renal cortical neoplasms are indicated.