Enterobius vermicularis infection mimicking liver malignancy

Background

Enterobius vermicularis is a common worm infestation of the bowel lumen; it has rarely been found outside the gastrointestinal tract. We review a case of hepatic enterobiasis mimicking haematologic disease.

Case description

In November 2021 and 2022 a 55 yo man developed two episodes of urticaria treated with steroids. During the first episode groin itching was also reported.

Blood tests showed eosinophilia (WBC 19030/mm3, Eos 67.1%), augmented total IgE (2108 IU/mL) and LFTs (liver function tests) (AST 69 IU/L, ALT 91 IU/L, GGT 127 IU/L) with negative viral hepatitis serologies as well as autoimmunity (ANA, antiDNA AMA, ASMA, antiLKM, ENA, ANCA). No ova nor worms were found in faeces (single sample tested). Sinus and chest CT scan showed no signs of Churg Strauss syndrome.

Liver ultrasound (LUS) showed mild hepatomegaly, non-homogeneous echo pattern with centimetric hypoechoic areas (Dec/2022). Abdomen MRI showed multiple and diffuse subverted structures of the liver (suggestive of lymphoma) and multiple lymph nodes (Apr/2023).

Due to persisting eosinophilia (WBC 8400/mm3, Eos 33.4%) and augmented total IgE (752 IU/mL) with abnormal LFTs (AST 59 IU/L, ALT 51 IU/L, GGT 138 IU/L, ALP 226 IU/L), patient underwent a first liver biopsy, suggestive of infectious etiopathogenesis: massive and confluent necrosis surrounded by histiocytes and numerous eosinophils, mild cholestasis and some eosinophils within the lobules, lymphohistiocytic inflammation with some eosinophils in the pericentral location; PAS, GMS, GROCOTT, WS and ZN stains were negative.

In May 2023 faeces were tested again: 1 out of 3 samples revealed Enterobius vermicularis ova. Serologies for Schistosoma and Trichinella were negative, as well as endoscopic searching for Anisakis.

Albendazole treatment (400mg once/weekly for 8 weeks) was administered, resulting in normalization of eosinophils count (4.8%, 300/mm3) and LFTs (AST 24 IU/L, ALT 27 IU/L, GGT 64 IU/L); moreover, a second liver biopsy showing normal pattern was performed after the aforementioned therapy, 6 months after the first one. Finally, a liver MRI confirmed the complete resolution of the abnormalities previously reported.

Conclusions

Ectopic localization of Enterobius vermicularis is rare. International literature reports six cases of liver infection, only two with modern imaging available, describing liver lesions as ill-defined, while diffuse hypoechoic areas were observed in our imaging. Treatment with albendazole (chronic recurrent course) resulted in normalization of the eosinophil count and LFTs; furthermore, histopathological lesions (necrosis and eosinophils infiltration) were no longer observed on the liver biopsy after appropriate therapy.