Ectopic Ascariasis Mimicking a Renal Mass: A Review of Aberrant Migration in Ascaris Lumbricoides

ABSTRACT. Ascaris lumbricoides infection is one of the most common helminthiases worldwide and is associated with poor sanitation in tropical and subtropical regions. Although most cases are asymptomatic or present with nonspecific gastrointestinal symptoms, aberrant migration may lead to ectopic disease. We present a case report of a 51-year-old woman with type 2 diabetes mellitus presented with progressive abdominal enlargement, gastrointestinal symptoms, and significant weight loss. Imaging studies revealed a large left perirenal mass initially interpreted as a renal neoplasm. She subsequently developed acute urinary retention and unexpectedly expelled a 30-cm reddish-brown cylindrical helminth with tapered ends, morphologically consistent with Ascaris lumbricoides . Complete symptom resolution and disappearance of the perirenal lesion on follow-up imaging supported the parasitic origin of the condition. This case illustrates a presentation of ectopic ascariasis with possible renal involvement, highlighting abnormal migration mechanisms such as fistulization or retrograde migration.