Histopathology of gastric and duodenal Strongyloides stercoralis locations in fifteen immunocompromised subjects.

Context: Strongyloidiasis is a worldwide parasitic infection affecting approximately 75 million people. In Italy, it was more prevalent in the past among rural populations of irrigated areas.

Objective: To determine the histopathologic alterations of the gastric and duodenal mucosa associated with the presence of Strongyloides stercoralis parasites.

Design: Fifteen cases of strongyloidiasis were observed in immunocompromised patients during a recent 6-year period in Italy. S. stercoralis was found histologically in gastric biopsies (10 cases), in a gastrectomy (1 case), and in duodenal biopsies (9 cases). In 5 cases the parasite was present both in gastric and duodenal biopsies. Four patients were affected by lymphoma, 2 by multiple myeloma, 2 by gastric carcinoma, 1 by chronic myeloid leukemia, 1 by sideroblastic anemia, 1 by colorectal adenocarcinoma, 1 by chronic idiopathic myelofibrosis, 1 by chronic gastritis, 1 by gastric ulcers, and 1 by rheumatoid arthritis in corticosteroid therapy. No patient was affected by human immunodeficiency virus infection. Strongyloidiasis was not clinically diagnosed.

Results: Histologic examination revealed several sections of S. stercoralis larvae, many eggs, and some adult forms. All the parasites were located in the gastric and/or the duodenal crypts. Eosinophils infiltrating into the lamina propria were found in all cases; their intensity was correlated with the intensity of the infection.

Conclusions: Histologic diagnosis of strongyloidiasis must be taken into consideration when examining both gastric and duodenal biopsies in immunocompromised patients, to avoid the development of an overwhelming infection of the parasite, which is dangerous for the life of the patient.