Colonic Strongyloides stercoralis With Multimodality Imaging, Endoscopic, and Histopathologic Correlation

We present a case of symptomatic colonic strongyloidiasis diagnosed in an immunocompetent patient with chronic peripheral eosinophilia, with an absolute eosinophil count ranging from 0.71-1.47 × 10^3/µL since 2013. Initial evaluation for persistent eosinophilia, including random colon biopsies, demonstrated increased eosinophils and mast cells within the biopsy fragments. The patient was subsequently lost to follow-up. In December 2025, the patient presented to the emergency department with left lower quadrant abdominal pain and loose bowel movements. Computed tomography demonstrated diffuse bowel wall thickening. Follow-up colonoscopy performed approximately three months later revealed diverticulosis and flat polyps. Random biopsies obtained from the left colon demonstrated focal Strongyloides stercoralis larvae within eosinophilic abscesses in the lamina propria. The patient received treatment with ivermectin and albendazole, with subsequent resolution of symptoms. This case highlights S. stercoralis infection as a potential consideration in patients with persistent unexplained eosinophilia and illustrates the role of histopathologic evaluation in establishing the diagnosis.