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.