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Caught on Colonoscopy: Schistosomiasis Manifesting as a Single Colonic Polyp

A screening colonoscopy identified an unexpected diagnosis in a 64-year-old male patient. He was an asymptomatic landscaper who presented for a first-time screening colonoscopy based on age. His only active medical issue was psoriasis, for which he took apremilast. At the time of colonoscopy, he denied any bright red blood per rectum, melena, changes in stooling habits, abdominal pain, nausea, vomiting, changes in appetite, weight loss, or night sweats. He did not report any family history of colon cancer. He was a lifelong nonsmoker and denied any current alcohol use. He lived in North Carolina in a home with his wife, 3 sons, 3 daughters-in-law, and a 2-year-old granddaughter. There were no pets in the home. He grew up in Luzon, Philippines, where he worked as a rice paddy farmer. He emigrated to the United States in 1995.


Physical examination was grossly unremarkable. Vital signs showed a blood pressure of 118/74 mm Hg, a pulse of 60 beats per minute, and a body mass index of 27.32 kg/m2. Conjunctiva were not pale, and sclera were anicteric. The oropharynx showed no suspicious lesions. No cervical or inguinal lymphadenopathy was noted. Abdominal examination showed a soft, nondistended, nontender abdomen with normoactive bowel sounds. Neither the liver edge nor the splenic tip was palpable. Extremities showed no significant edema. Skin examination was notable for a few scaly, dry patches on bilateral arms and legs, consistent with prior psoriatic lesions.


The patient underwent screening colonoscopy. He had hemorrhoids on perianal examination. A 10-mm flat polyp was found in the cecum (Figure 1) and removed with a saline injection-lift technique. A second 3-mm sessile polyp was found in the cecum and removed. Resection and retrieval were complete for both polyps. Aside from a few small diverticula in the sigmoid colon, no other abnormalities were noted. The quality of the bowel prep was noted to be “excellent.” Microscopic examination of the cecal polyps showed numerous round-to-oval parasite ova in the submucosal tissue. Based on the morphology and size of the ova, the pathologist reported that this was consistent with schistosomiasis. He underwent subsequent stool testing, which was positive for Schistosoma japonicum (Figure 2). Urine microscopy was negative. Complete blood count showed a normal absolute eosinophil count of 0.23 × 109/L. Hepatic function panel was also normal.

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-Jessica Seidelman, MD, Edward F. Hendershot, MD, Nancy Henshaw, PhD, Matthew Rein, MD

This article originally appeared in the November issue of The American Journal of Medicine.

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