Colonic polyp secondary to Anisakis simplex
Pólipo de colon secundario a Anisakis simplex
Key words: Anisakis. Eosinophilic granuloma.
Palabras clave: Anisakis, granuloma eosinofílico.
]]> Dear Editor,
The nematode Anisakis simplex is a parasite spread world-wide which infects consumers of raw or barely cooked fish. Clinically, it manifests itself in varied ways, from asymptomatic patients to others with allergic or digestive symptoms depending on the part of the digestive tract in which the larva lodges. We here present a case of incidental discovery of colonic eosinophilic granuloma, secondary to anisakiasis in an asymptomatic patient.
Case report
A woman of 47-years of age, with no antecedents of interest, consulted because of rectal bleeding; the patient denied other accompanying symptoms, no abdominal pain, nor any alterations of bowel movements, no loss of weight. Physical examination was normal, except for the presence of hemorrhoids upon anal examination.
Blood counts were strictly normal. A colonoscopy was requested, during which a submucosal polyp was observed (Fig. 1) and removed. Histopathology of the removed lesion demonstrated an eosinophilic granuloma secondary to Anisakis parasite (Fig. 1).
Discussion
]]> Clinical manifestations of anisakiasis are quite varied, mainly of allergic and/or gastrointestinal types, and they are due to two mechanisms: a) immediate hypersensitive reactions measured by IgE: patients develop allergic reactions such as rash few hours after eating fish; and b) local action of the parasite: symptoms develop as a result of an inflammatory reaction, when the larva's head sticks or lodges in the mucous membrane of the digestive tract (2). Clinical manifestations will depend on the area of the digestive tract where the larva is found. The most frequent location is the stomach or the small bowels (3).Gastric anisakiasis is characterized by abdominal pain located in epigastrium, often accompanied by nausea, vomits or even altered bowel function, if it affects the duodenum. When the process is chronic, formation of abscess, or gastric or intestinal granuloma may have symptoms similar to suboclusive episode, acute apendicitis or episodes of inflammatory bowel disease (4). Bibliography (4-9) refers to eosinophilic granulomas secondary to Anisakis located in the stomach or the small bowel, but not in the colon, and always as secondary findings to a set of symptoms which provoked the search. In our case, the patient had no symptoms at any time and the discovery was incidental in a colonoscopy required for another reason. Due to the great consumption of fresh fish, a high prevalence in immunoalergic tests in asymptomatic patients is observed, and for the same reason there may be asymptomatic infestations as in the case we have presented. It is not possible to determine if, in time, the lesion found would have evolved and the patient would have presented suboclusive symptoms or of any other kind.
María Teresa Herranz-Bachiller, Ramón Atienza-Sánchez, Jesús Barrio-Andrés, Noelia Alcaide-Suárez,
Rafael Ruiz-Zorrilla, Lorena Sancho-del-Val, Carlos de-la-Serna-Higuera and Manuel Pérez-Miranda
Hospital Universitario Río Hortega. Valladolid, Spain
References
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