OMED E-Newsletter Issue 5, 2009: Brainteaser/image of the month
This lesion was found on the anterior wall of the gastric body in a 52 year old man. Previous surface biopsies had only shown a large number of eosinophils infiltrating the mucosa and immunohistochemistry has been negative when staining for desmin.
What is the likely diagnosis?
- gastric lymphoma
- benign gastic ulcer
- gastro intestinal stromal tumour (GIST)
- early gastric cancer
- inflammatory fibroid polyp
Explanation
The correct answer is e. The Correct answer is E. This is an inflammatory fibroid polyp (eosinophilic granuloma). These are rare benign lesions arising from the submucosa. They can occur throughout the digestive tract, in descending order of frequency; stomach (88%), small intestine, and large intestine. The peak prevalence is in the 60 - 65 year old.
The clinical presentation varies according to the location, frequently they are mistaken as gastrointestinal neoplasias. Abdominal pain and anaemia due to chronic blood loss are the most common presenting features in gastric inflammatory fibroid polyps. Intestinal obstruction is one of the manifestations, mainly when the lesion occurs nearby the ileum caecal region.
Endoscopically, most are smooth, sessile or semi-pedunculated lesions usually found in the antrum (75% of cases). All lesions larger than 1 cm will have a central erythematous depression or ulcer.
On EUS, these lesions are located in the second and/or third sonographic layer of the gastric wall without involvement of the fourth layer.
The characteristic histological feature of these lesions is an eosinophil-containing, loosely structured fibrous tissue comprising an onion-skin-like arrangement of reticular fibers with spindle-shaped nuclei localized in the submucosa and the base of the mucosa. Immunohistochemistry is always positive for vimentine and negative for S 100 and desmin. These lesions are best removed by endoscopic mucosal resection