Su2012 A First Case Report of Colorectal Cancer Associated With Chronic Strongyloides Stercoralis Colitis and the Complex Management Decisions That Follow

Abstract

Rarely pathogenic organisms including parasites can act as carcinogens. To our knowledge, there are no reported cases regarding the association between a Strogyloides stercoralis infection and colon cancer. A 47 year old Columbian man with Vitiligo presented to our Emergency Room with fatigue, 25 lb weight loss in 6 months and iron deficiency anemia. He denied diarrhea or blood per rectum and there was no personal or family history of malignancy, celiac or IBD. On admission, the physical exam was notable for vitiligo and a positive guaiac. The hemoglobinwas 3.1 gm/dL and 26.4% eosinophilia was seen. Endomysial Ab, ESR, and CRP were all normal. 5 units of PRBC's were transfused. The patient had a normal EGD and colonoscopy 6 yrs prior for the workup of anemia, but there were no records available to review. Both EGD and colonoscopy were then performed at our institution. The EGD was grossly normal and biopsies of the duodenum were obtained to exclude occult celiac. The colonoscopy, however, demonstrated a severe right sided colitis, with friable granular mucosa, erosions and confluent loss of vascular markings and haustral folds. In addition, a 3cm ulcerated mass was identified in the colitic ascending colon and biopsies confirmed invasive low grade adenocarcinoma. Of interest, the ileal and rectosigmoid mucosa appeared grossly normal. No metastasis were identified on abdominal and chest CT and the surgeons scheduled a total colectomy for presumptive IBD associated dysplasia. The stool studies and duodenal biopsies returned positive for Strongyloides stercoralis. Treatment was initiated with 2 doses of Ivermectin 200mcg/kg/d. At tumor board, the pattern of a colitis secondary to Strongyloides rather than IBD was emphasized with the consensus for an extended right hemicolectomy with ileocolic anastomosis. Intraoperatively the left colon appeared grossly normal, surgical staging confirmed a T3N0M0 tumor, stage 2b. Given the concerns for hypereosinophilic syndrome with immunosuppressive therapies, fecal confirmation of strongyloides eradication was confirmed 12 weeks postop. Adjuvant chemotherapy was offered but the patient declined after explanation of the risks and benefits. To date, the patient remains asymptomatic and surveillance colonoscopies at 6 months and 2 yrs have demonstrated no evidence of gross colitis or dysplasia, reaffirming the infectious etiology. This case illustrates the only known association of chronic colitis and colon cancer due to Strongyloides stercoralis. In atypical chronic colitis, and in populations at risk for Stronyloidiasis, it is essential to exclude this parasite prior to potentially life threatening immunosuppression that one would choose to treat IBD. However, dysplasia surveillance should also be considered given the potential for malignancy as demonstrated in this patient with strongyloides chronic colitis.