[A case of adult Wilms' tumor--review of the literature on histopathological features and prognosis].

A case of Wilms' tumor in a 57-year-old woman is reported. She was with a complaint of a palpable mass on the right upper abdomen. CT scan showed a non-hemogenous mass arising from the lower pole of the right kidney. After transarterial embolization, right transabdominal radical nephrectomy was performed under the diagnosis of renal cancer. Histopathological study revealed Wilms' tumor stage 2. Over the two years after surgery the patient is disease-free. Wilms' tumor is rare in adults. The prognosis of adult Wilms' tumor is recognized to be poorer than that of children. Recently, Wilms' tumors in children are classified into two histopathological groups, that is "favorable histology" and "unfavorable histology" according to the cell differentiation. Based on a collection of the previous Japanese and English reports, we analyzed the relationship between the histopathological features and the prognosis in adult Wilms' tumor. Ten cases of unfavorable histology have very poor prognosis, with the two year survival rate of 22%. In contrast, that of 24 cases of favorable histology was 71%. In particular, all cases of the epithelial predominant type presenting favorable histology, including stag 4 cases, survived over two years. Our case was the epithelial predominent type presenting favorable histology. That is probably one of the chief reasons of the good prognosis. In conclusion, the above-mentioned results show that in adult Wilms' tumor, the prognosis of unfavorable histology is very poor, but that of a low stage or the epithelial type presenting favorable histology is, as in children, relatively good.