Adult Wilms' tumor with calcification untreated for 5 years – a case report

BACKGROUND Wilms' tumor is rarely found in adults and there are no established treatment guidelines for such tumors in adults. Whereas calcification is a common finding in neuroblastoma, it is considered uncommon in Wilms' tumor. CASE PRESENTATION We report a case of adult Wilms' tumor with calcification in a 22-year-old man. He had been initially referred to our hospital with a chief complaint of right flank pain 5 years previously, when abdominal computed tomography had revealed focal calcification at the upper pole of the right kidney. Although we planned further assessment, he did not revisit our hospital again until 5 years later, again because of right flank pain. Ultrasound and computed tomography scan revealed a large mass lesion with calcification in the right kidney, invasive to the hepatic lobe. The patient underwent curative right nephrectomy and partial right hepatic lobectomy. Pathological analysis demonstrated a nephroblastoma (Wilms' tumor) with predominant epithelial histology infiltrating the hepatic lobe. The patient has been well without tumor recurrence for 15 months after surgery. CONCLUSIONS Calcification may be a sign of slow tumor growth and possibly a favorable prognosis in cases of adult Wilms' tumor.