2020 Volume 56 Issue 4 Pages 414-420
A 14-year-old boy who developed left-side abdominal pain three months ago visited a previous clinic owing to repeated pain. Abdominal contrast CT showed a 10 mm mass near the spleen, and it was suspected as a torsion of the accessory spleen. He was referred to our hospital, and contrast MRI showed the same mass near the spleen. The mass was not enhanced, suggesting that an accessory spleen was infarcted. Two months later, laparoscopic resection was performed. During the operation, we found a mass in the greater omentum near the spleen and resected it. It was a white and solid mass measuring 10 × 10 mm. Histopathological examination showed that the mass was a granuloma with neutrophil infiltration, and a necrotized worm was found in the granuloma. The worm had a Y-shaped lateral cord and a renette cell indicating that it was an Anisakis larva; therefore, we diagnosed the patient as having extra-gastrointestinal anisakiasis. In the first infiltration of Anisakis larvae to the body, a few larvae may penetrate the abdominal wall and die in the abdominal cavity. Extra-gastrointestinal anisakiasis develops when the larva forms a granuloma in the abdominal cavity. The occurrence frequency of this disease is only 0.5% of all types of anisakiasis, and the preoperative diagnosis is very difficult. Thus, most cases were found accidentally during the operation, but a few were found because of abdominal pain due to the granulomas. From our experience, clinicians should consider the possibility that the granuloma due to extra-gastrointestinal anisakiasis may also cause abdominal pain.
