The objective of this study was to evaluate the relationship between Enterobius vermicularis and the occurrence of acute appendicitis. Over a ten year period of time, all appendix specimens received by the department of pathology were reviewed for pathologic changes and the existence of E. vermicularis. Logistic regression was carried out to determine the odds ratio (OR) of the relationship between E. vermicularis and acute appendicitis. A total of 5048 specimens were reviewed. E. vermicularis was found in 144 (2.9%) cases. After separating by sex and adjusting for age logistic regression analysis showed the OR of E. vermicularis appendiceal infestation was 1.275 (95% CI = 0.42-3.9) for males and 1.678 (95% CI = 0.61-4.65) for females. Age was an independent risk factor for acute appendicitis in males (OR = 1.01, 95% CI = 1.003-1.017) and females (OR = 1.012, 95% CI = 1.005-1.02).

Appendiceal enterobiasis--its incidence and relationships to appendicitis.Folia Parasitol (Praha). 1984;31(4):311-8.

An evaluation was made of a bioptic material (21,916 appendices recovered from 1965 to 1974), in order to disclose relationships of the incidence of Enterobius vermicularis and the origin of appendicitis. A separate evaluation was made of a set of appendectomies (10,619 cases--from 1961 to 1970) for the purpose of detecting changes in pin worm-infested appendices by means of histological methods (683 cases). E. vermicularis was found in 6.03% of appendices. Included in our histological examination was a search for granulomas and eosinophile infiltrations. The former occurred in 1.14% of pin worm-infested appendices, the later in 1.74% and in 0.19%, or 2.18% in pin worm non-infested appendices. The results indicated a statistically highly significant difference in the incidence of granulomas. The incidence of granulomas in the appendix was increased in the present of pin worms in the appendix, and seemed also to be responsible for further pathological changes in it.

Enterobiasis: a histopathological study of 259 patients.Ann Trop Med Parasitol. 1991 Dec;85(6):625-35.

Enterobius worms or their eggs, or both, are present in preserved tissue sections or tissue specimens of 259 patients whose medical records are on file at the Armed Forces Institute of Pathology, Washington D.C., U.S.A. The most common site of infection (86.5%) was found to be the lumen of the appendix, where the worms provoke no reaction. Of the 259 patients 11 (4.2%) had worms and/or eggs in granulomas of the abdominal and pelvic peritoneum, and an equal number had granulomas on the peritoneum of the salphinx or on the surface of the ovary. There were also ectopic worms and/or eggs in granulomas on the peritoneum of the small and large intestines (2.7%). These Enterobius granulomas form around degenerating adult worms, around discrete eggs, around clusters of eggs, and, we believe, also around the tracks of migrating worms. Three patients (1.2%) had worms in perianal abscesses. A necrotic granuloma, removed from the lung of one patient, surrounded a degenerating adult worm. This suggests that the worm, carried to the lung as an embolus, impacted in a pulmonary arteriole. A stool specimen of one patient contains eggs of Enterobius, and that of another patient contains an adult Enterobius. This is the largest recorded histopathological study of enterobiasis in man.