Schistosomiasis as a Solitary Sigmoid Nodule

A healthy thirty-year old man, who had emigrated from rural Brazil seven years earlier, presented with one and a half years of chronic diarrhea. Stool evaluation was negative for ova and parasites, negative for fecal leukocytes and had normal flora on culture. Colonoscopy was normal except for one 4mm nodule in the sigmoid colon that had the appearance of a submucosal lipoma (Figure 1). Histologic examination of the sigmoid nodule demonstrated multiple non-necrotizing granulomas in the lamina propria surrounded by a dense inflammatory infiltrate composed of eosinophils (Figure 2, H&E, 100X). The center of some granulomas contained calcified material, morphologically compatible with Schistosoma eggs, approximately 80 microns in diameter (Figure 3, H&E, 200X). In light of these findings, he was given oral Praziquantel 1200mg for three doses with complete resolution of symptoms.

Figure 1.

Figure 2.

Figure 3.