Anisakiasis and vanishing tumor of the cecum.

vanishing gastric tumors caused by anisakiasis [1]. The large intestine is rarely affected because the ingested larvae usually do not travel that far down the gastrointestinal tract. Colonic anisakiasis occasionally resembles a colonic tumor, because it leads to edema, acute phlegmonous inflammation, or the formation of granulomas around the larvae in the submucosa of the intestinal wall [2]. A 77-year-old man attended our hospital for a positive fecal occult blood test. He was asymptomatic. He had a history of appendectomy for acute appendicitis at the age of 19 and ate raw fish almost every day. His white blood cell count was normal with no eosinophilia. At colonoscopy, a clearly demarcated, depressed lesion with raised margins (similar to a Borrmann type 2 lesion) was identified in the cecum (●" Fig. 1). The histopathological examination of the biopsy specimens revealed eosinophilic infiltration of the lamina propria mucosae and the submucosa, and necrosis of the epithelium (●" Fig. 2). Malignant cells were not seen. Computed tomography showed wall thickening in the cecum (●" Fig. 3). On repeat colonoscopy after 16 days, the tumour resembling a Borrmann type 2 lesion had disappeared and a reddish scar with small erosion was seen in the cecum (●" Fig. 4). Serum titers of both IgG and IgA antibodies to Anisakis larvae on the day of the second colonoscopy were slightly elevated at 1.61 (cut-off index, normal < 1.50). At another colonoscopy a year later, the tumor had completely disappeared and a whitish scar was seen in the cecum (●" Fig. 5). The vanishing tumor may be considered to be anisakiasis of the cecum. Anisakiasis and vanishing tumor of the cecum