Endoscopic Finding of a Large Vanishing Tumor

A 59-year-old Japanese man was referred to our hospital in March 1998 due to an acute onset of upper abdominal pain, which had occurred a few hours after ingesting raw mackerel. The physical examination showed epigastric tenderness. Upper endoscopy identified a reddish tumor, 65 mm in its largest diameter, in the gastric fundus (Figure [1]). The tumor had a smooth surface, with irregular and shallow ulcers covered by blood coagula. The patient’s abdominal pain subsided immediately, without any treatment. An upper endoscopic examination carried out two weeks later revealed that the tumor had regressed (Figure [2]). At this time, the patient’s serum IgGI-A antibody titer to Anisakis larvae increased to 2.09 (normal: < 1.50). On the basis of these findings, a diagnosis of gastric anisakiasis was established. The patient has been free of any gastrointestinal symptoms during a subsequent follow-up period of 26 months.

Gastric anisakiasis is a condition characterized by infestation of Anisakis larvae in the gastric mucosa after the ingestion of raw or undercooked fish. The clinical, radiological, and endoscopic features of the disease have been well documented [1]. Yamasaki et al. [2] were the first to report a gastric protrusion of obscure origin that rapidly regressed, and described these lesions as “vanishing tumor.” It is presumed that the lesion is caused by penetration of the Anisakis larvae into the gastric wall [3] [4] . The common endoscopic feature of the tumors is a smooth protrusion. As in the case described here, vanishing tumors caused by anisakiasis have also previously been observed in the gastric fundus [3] [4] .

Vanishing tumor is easily diagnosed by endoscopy. However, Anisakis larvae have rarely been confirmed by the procedure [5]. In the present case, increased antibody to Anisakis larvae was the key to the diagnosis. Vanishing tumors should not be misdiagnosed as neoplastic lesions, and serological testing for Anisakis larvae should be considered when there are similar findings.

Figure 1Upper endoscopy reveals a reddish tumor in the gastric fundus. The tumor has a smooth surface and shallow ulcers

Figure 2Upper endoscopy two weeks later shows that the tumor has regressed

References

• 1 Kakizoe S, Kakizoe H, Kakizoe K, et al.. Endoscopic findings and clinical manifestation of gastric anisakiasis.  Am J Gastroenterol. 1995;  90 761-763
• 2 Yamasaki M, Hara K, Shinbo T.. On vanishing tumor of the stomach (in Japanese).  Jpn J Clin Radiol. 1978;  23 919-924
• 3 Matsukuma A, Mori M, Ooiwa T, et al.. Vanishing tumor of the stomach.  Am J Gastroenterol. 1987;  82 1102-1103
• 4 Takeuchi K, Hanai H, Iida T, et al.. A bleeding gastric ulcer on a vanishing tumor caused by anisakiasis.  Gastrointest Endosc. 2000;  52 549-551
• 5 Kinoshita Z, Kinoshita K, Hino K, et al.. Two cases of acute gastric lesion assuming the form of gastric vanishing tumor (in Japanese).  Gastroenterol Endosc. 1984;  26 884-888