Schistosoma japonicum infection and rectal carcinoid tumour: underreported coincidence or neglected association?

Schistosoma japonicum infection associated with a rectal carcinoid in an asymptomatic 44-year-old female from the Philippines is described. A systematic review of the literature could not identify similar reports, suggesting a rare coincidence. However, epidemiological data on the frequency of both conditions as well as published results of a colorectal screening programme from China indicate that underreporting of this concurrence is likely. Moreover, several studies suggest a causal link between schistosomiasis caused by S. japonicum and more common gastrointestinal malignancies such as colorectal carcinoma. Hence the presented case and the apparent neglect of this observation in the current literature allow speculation on a role of S. japonicum in the pathogenesis of rare gastrointestinal neoplasms such as carcinoid tumours as well. Future reports on similar observations could help to determine the need for systematic investigations and are strongly encouraged.