# Rare Enterobius vermicularis infection of the greater omentum misdiagnosed as schistosomiasis: a case report

## TL;DR

A 12-year-old girl was misdiagnosed with schistosomiasis when she actually had a rare pinworm infection in her omentum, highlighting the need for better parasite identification training.

## Contribution

This case report highlights the misdiagnosis of ectopic enterobiasis as schistosomiasis and emphasizes the need for improved training in parasitic morphology.

## Key findings

- Ectopic enterobiasis in the greater omentum was misdiagnosed as schistosomiasis due to morphological similarities.
- Expert consultation confirmed the presence of an adult Enterobius vermicularis containing eggs in the omental mass.
- The patient had a prior pinworm infection and was successfully treated with albendazole, resolving perineal pruritus.

## Abstract

Enterobiasis, caused by Enterobius vermicularis, is a common intestinal parasitic infection in children. Ectopic migration to extraintestinal sites, such as the greater omentum, is rare and often misdiagnosed due to nonspecific clinical manifestations and limited proficiency in identifying parasitic structures in paraffin-embedded histological sections.

A 12-year-old female presented with a three-day history of lower abdominal pain and a pelvic mass. Emergency laparoscopic resection revealed an ovarian serous cystadenoma and an omental mass. Initial histopathological examination of the omental mass suggested schistosome eggs; however, expert consultation confirmed a section of an adult female E. vermicularis containing eggs measuring up to 50 μm. The patient had no exposure to schistosomiasis-endemic areas but a history of prior pinworm infection, which had been treated with oral albendazole (400 mg once daily for 2 days). Subsequent adhesive tape tests over three consecutive days were negative, and perineal pruritus was resolved, confirming successful cure. The final diagnosis was ectopic enterobiasis of the greater omentum.

This case underscores the critical role of accurate morphological identification in distinguishing parasitic infections. Misdiagnosis, even in non-schistosomiasis-endemic areas, reflects insufficient training in parasitic morphology among healthcare professionals. Enhanced training on the morphology of common parasites and interpretation of paraffin-embedded histological sections is essential to improve diagnostic accuracy.

The online version contains supplementary material available at 10.1186/s40249-026-01429-6.