Adult Wilms' tumor presenting as acute abdomen with elevated serum lactate dehydrogenase-4 and -5 isoenzymes: case report.

Wilms' tumor, an embryonic neoplasm, is the most frequent renal tumor in childhood but is rare in adults. The prognosis of adult Wilms' tumor is worse than pediatric Wilms' tumor. The preoperative diagnosis of adult Wilms' tumor is extremely difficult to make because diagnostic imaging techniques, such as intravenous pyelography, computed tomography, ultrasound, renal angiography, and nuclear magnetic resonance imaging, only confirm the presence of a renal mass. Diagnosis usually depends on histological characteristics, such as the presence of blastemic, epithelial, and mesenchymal components. A 27-year-old female presented with acute abdomen and with elevated serum lactate dehydrogenase (LDH) at 212 U/l (normal range: 47-140), and 2 of 5 LDH isoenzymes, namely LDH-4 at 13.6% (normal range: 6.8%-10.2%) and LDH-5 at 20% (normal range: 6.5%-9.7%). In this patient, stage I Wilms' tumor was managed by radical nephrectomy. The levels of LDH returned to its normal range. In conclusion, in cases of acute abdomen with a renal mass in young adults, the possibility of Wilms' tumor should be considered. Serum LDH and its isoenzymes, LDH-4 and LDH-5, could be used as tumor markers for either differential diagnosis or monitoring the response of treatment.