Possible associations of rectal carcinoma with Schistosoma japonicum infection and membranous nephropathy: a case report with a review

We report the first case of rectal carcinoma associated with S. japonicum a nd membranous nephropathy. A 57-year-old Japanese man noticed narrowing of his feces. He had lived in Yamanashi prefecture, an endemic area of S. japo nicum. He had suffered from nephrotic syndrome for about 1 year. Barium ene ma study showed a severe stricture in the upper rectum and biopsy specimens from the tumor demonstrated well differentiated adenocarcinoma and many ov a of S. japonicum. Sonography of the liver showed a network pattern and a l inear high echoic area, Low anterior resection with incisional biopsy of th e liver and the right kidney was performed. Histopathological findings show ed well differentiated adenocarcinoma and schistosomal ova. The total numbe r of ova in the resected colon amounted to 15 133, consisting of 2243 insid e and 12 890 outside the carcinoma. The nearer to the carcinoma the area wa s, the higher was the density of ova. The findings of light microscopy and electron microscopy of the biopsy specimen from the kidney were compatible with membranous nephropathy (stage II), This case suggests that schistosoma l ova have some effect on carcinogenesis and nephrotic syndrome. In patient s with nephrotic syndrome of unknown cause, especially in inhabitants of en demic areas of S. japonicum, gastrointestinal malignancy should be ruled ou t as an etiological factor. Sigmoidoscopy would be useful for colorectal ca rcinoma surveillance in S. japonicum patients.