Abstract

A histologic classification based on tumor differentiation, degree of tubular formation and favorable histology versus unfavorable histology was applied in a retrospective study of 21 patients with Wilms tumor to determine if it might provide an index to prognosis from 1977 through 1987. A comparison of the histologic findings with survival through statistical analysis was undertaken and it was found that the histologic classification was significantly correlated with survival. The results were as follows: 1. Low grade tumors(grade I) with predominance of differentiated tubules & glomeruli were associated with better survival rate than high grade tumorrade III) composed mainly of undiffer- entiated spindle elements: 2-year survival rate was 100% for grade I with 11% for grade III (p< 0.01). 2. Survival rate was lower for the low degree of tubular formation than for the high degree of tubular formation: 2-year survival rate were 14%, 50%, 75%, 100% for group 0, +, ++, and +++ respectively(p < 0.05). 3. 11 patients with the focal or diffuse anaplasia and sarcomatous stroma (unfavorable histology) had poor prognosis, giving 36% of 2-year survival rate but 10 patients with favorable histology had 70% of 2-year survival rate (p<0.05).