Case Presentation: A 48 year-old male presented Landstuhl Regional Medical Center with epigastric pain and fevers that had progressed to pain in the right lower quadrant. He lived in Cameroon until 30 years old and had recently deployed to West Africa. Computed Tomography (CT) of his abdomen demonstrated thickening of his right colon with extra-luminal focal air concerning for a contained perforation. He was admitted for intravenous antibiotics however repeat CT showed irregular thickening of the cecum concerning for malignancy. Right hemicolectomy revealed a cecal mass ultimately diagnosed as diffuse large B cell lymphoma (DLBCL). Additionally, mucosal tissue taken from the right colon revealed adjacent eosinophilic granulomas with ova most consistent with Schistosoma mansoni. The patient began chemotherapy with dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab (DA-EPOCH-R) with Ibrutinib. Prior to chemotherapy he was treated with praziquantel for treatment of the S.mansoni as well as ivermectin due to the risk of being co-infected with Strongyloides stercoralis, which can lead to hyperinfection syndrome or disseminated disease in immunocompromised patients.

Discussion: Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin lymphoma. Schistosomiasis is an infectious disease caused by flatworms that affects almost 200 million people. While Schistosoma haematobium is a well-documented cause of bladder cancer, the association between Schistosoma and other forms of cancer is limited to case reports. Humans are infected by Schistosomiasis by swimming in freshwater with infected snails whose larvae penetrate the skin and lodge in tissues producing a granulomatous inflammatory response. Untreated, these eggs can produce long-term sequelae. For example, S. haematobium is associated with bladder cancer. Current research suggests this process is multifactorial, but chronic inflammation plays a major role. The research regarding the carcinogenic potential of S. mansoni is less clear. Although S. mansoni has also been shown to produce chronic inflammation, the association of S. mansoni with malignancy has been limited to case reports.

Conclusions: Development of DLBCL with concomitant S. mansoni infection in particular is a rare phenomenon and our review of the literature uncovered only one other case report of a 19 year-old Nigerian woman. Despite this, an understanding of bladder cancer with S. haematobium infection provides a potential mechanism for S. mansoni leading to DLBCL. Particularly relevant to hospital medicine is the prompt treatment of this infection along with presumed S. stercoralis before beginning chemotherapy in order to prevent hyperinfection syndrome.

IMAGE 1: Granuloma with Schistosoma mansoni

IMAGE 2: Computed Tomography (CT) scan shown here reveals cecal mass