Wilms' tumor (WT), also called nephroblastoma, is an embryonic neoplasm of the developing kidney. A previously healthy Japanese female infant had WT in a single kidney without associated congenital malformations. Preoperative chemotherapy was started for the preservation of renal tissue and function. Tumor lysis syndrome, disseminated intravascular coagulopathy, and acute renal failure were accompanying. The infant needed surgical intervention and permanent replacement therapy. At the start of emergency hemodialysis, the infant had posterior reversible leukoencephalopathy syndrome because of severe hypertension. During ongoing peritoneal dialysis, the infant suffered from anemia, dietary and fluid restriction, and restriction of time and mobility. Despite alfacalcidol and calcium supplementation, the infant had secondary hyperparathyroidism and remarkably short stature. After waiting for the completion of chemotherapy, renal transplantation from the mother was completed. Successful kidney transplantation promptly corrected preexisting metabolic abnormalities causing secondary hyperparathyroidism. Subsequently, the infant often complained of headache. Computed tomographic scanning revealed calcification in the cerebellum. Refractory secondary hyperparathyroidism was inferred as the cause. A well-functioning graft provided the infant with a greater sense of well-being and enabled her to enjoy a lifestyle free of dialysis, although the infant must continue taking transplant medications and has retained unresolved issues of short stature and ectopic intracranial calcification.