Wilms' tumor. Role of fine needle aspiration and DNA ploidy by image analysis in prognostication

OBJECTIVE: To evaluate the utility of cytomorphologic features and DNA ploidy estimation in fine needle aspirates (FNAs), from Wilms' tumors for prognostication. STUDY DESIGN: Twenty-three cases of Wilms' tumor having FNA and follow-up data were selected. Cytomorphology was analyzed by two observers. DNA ploidy was determined in 19 cases by image cytometry by destaining Papanicolaou-stained slides and restaining with Feulgen stain. Various parameters and patient outcomes were compared, and statistical evaluation was done. RESULTS: Poor outcome (12/23 cases) was associated with age < 2 years (P = .01), severe pleomorphism of blastemal cells (4/23 cases, P < .05), very large nucleoli (5/23 cases, P = .075), atypical mitosis (6/23 cases, P = .032) and aneuploidy/tetraploidy of tumor cells (6/29 cases, P = .005). Term unfavorable cytology is proposed when a combination of severe pleomorphism, very large nucleoli and atypical mitosis is seen in FNA smears. Four Wilms' tumor FNAs were characterized as showing unfavorable cytology, and all had a poor outcome (P = .0351). Three of the six cases with aneuploid/tetraploid features also showed unfavorable cytology. CONCLUSION: Unfavorable cytology and aneuploidy/tetraploidy in FNA smears of Wilms' tumor are associated with a poor prognosis.