Primary adenocarcinoma of the bladder: favorable prognostic significance of deoxyribonucleic acid diploidy measured by flow cytometry. Flow cytometric nuclear deoxyribonucleic acid ploidy analysis was done successfully on 38 specimens of primary bladder adenocarcinoma treated between 1954 and 1985. Of the specimens 10 (26%) were deoxyribonucleic acid diploid, 8 (21%) were tetraploid and 20 (53%) were aneuploid. Distribution of ploidy patterns between the 14 histological low grade and 24 high grade tumors was similar. Of 38 tumors 35 (92%) showed muscle invasion. One tumor arose in a previously exstrophied bladder, 10 were of urachal origin and 27 arose in an anatomically normal bladder. Of the urachal origin tumors 80% were deoxyribonucleic acid aneuploid. At 5 and 10 years after diagnosis 80 and 70%, respectively, of the patients with diploid tumors were free of disease. By contrast, at 5 and 10 years after treatment only 20 and 12%, respectively, of the patients with nondiploid tumors have not had disease progression (p less than 0.001 log-rank test). None of the 6 patients with diploid, high grade, high stage, muscle invasive tumors had subsequent progression. In contrast, 16 of 17 patients (94%) with high grade, high stage, nondiploid tumors had either local or distant tumor recurrence (p less than 0.0005). Nuclear deoxyribonucleic acid ploidy pattern appears to be the most significant prognostic information currently available to stratify expected prognosis for patients with muscle invasive adenocarcinoma of the bladder. This test probably should be a standard tool in the clinical management of patients with this rare bladder malignancy. 