Difficulty swallowing solid foods; food ‘getting stuck in the chest’
WHAT IS THE DIAGNOSIS?
2. Which is the most likely diagnosis for our patient?
- Fundic gland polyps
- Gastric hyperplastic polyps
- Gastric adenomas
- Mucosa-associated lymphoid tissue (MALT) lymphoma
Fundic gland polyps are small (0.1–0.8 cm), hyperemic, sessile, flat, nodular lesions that have a smooth surface. They occur exclusively in the gastric corpus and are composed of normal gastric corpus-type epithelium arranged in a disorderly or microcystic configuration. 11 This pattern does not match our patient’s findings.
,Gastric hyperplastic polyps are elongated, cystic, and distorted foveolar epithelium with marked regeneration. Other histologic findings are stromal inflammation, edema, and smooth muscle hyperplasia.12 This does not match our patient’s findings.
Adenomas can be flat or polypoid and range in size from a few millimeters to several centimeters. Endoscopically, adenomatous polyps have a velvety, lobulated appearance. Most are solitary (82% of cases), located in the antrum, and less than 2 cm in diameter.13 This does not match our patient’s findings.
MALT lymphoma, the correct answer, is characterized by small cleaved lymphocytes positive for CD4, CD20, and CD43. Although CD5 positivity is not characteristic, rare cases of MALT lymphoma may be CD5-positive and may be more aggressive.14
Other common features of MALT lymphoma are erosions, small nodules, thickening of gastric folds—generally suggesting a benign condition—or hyperemic or even normal gastric mucosa.15 Our patient’s complaint of food sticking in her chest and difficulty swallowing was most likely related to the erosive esophagitis found on endoscopy.
A TYPE OF NON-HODGKIN LYMPHOMA
Normal gastric mucosa contains no lymphoid tissue.16,17 Primary gastric lymphoma, of which MALT lymphoma is a subtype, accounts for around 5% of gastric malignancies, with an annual incidence rate of 0.5 per 100,000 people. 18–20 Although rare, it accounts for 60% to 70% of cases of non-Hodgkin lymphoma of the gastrointestinal tract and can involve the perigastric or abdominal lymph nodes or both.21–23 Although earlier studies suggested that its incidence was increasing, recent data indicate the incidence may be decreasing, thanks to active H pylori treatment.24–26
Two subtypes of primary gastric non-Hodgkin lymphoma commonly described are MALT lymphoma and diffuse large B-cell (DLBC) lymphoma. In the Revised European-American Lymphoma Classification, high-grade MALT lymphoma is comparable to DLBC lymphoma and may have transformed from low-grade MALT lymphoma.27,28 Another reported subtype, mantle cell lymphoma with MALT lymphoma features, should be considered in the differential diagnosis, although it is rare.29
MALT lymphoma is linked to H pylori
H pylori infection is a factor in the development of MALT lymphoma,30 as multiple lines of evidence show:
- H pylori infection has been reported in more than 90% of patients with MALT lymphoma.31–35
- H pylori antibodies have been found in stored serum drawn from patients who subsequently developed MALT lymphoma.35
- In response to H pylori antigens, T cells from MALT lymphoma proliferate and cause an increase in tumor immunoglobulin production.36
- In animals experimentally infected with H pylori, around one-third develop lymphoid follicles and lymphoepithelial lesions including B cells, which are similar to human MALT lymphoma.37
However, only a minority of patients with H pylori develop lymphoma, owing to a host immune response that is not well defined.
Second highlight point
- Gastric MALT lymphoma is associated with H pylori.
Associated genetic translocations
Three translocations, t(11;18), t(1;14), and t(14;18), are specifically associated with MALT lymphoma, and the genes involved have been characterized.
The t(11;18) translocation, seen in gastric and nongastric MALT lymphoma, is not seen in H pylori gastritis.38 This translocation is usually associated with extension of the disease outside the stomach (ie, to regional lymph nodes or distal sites).27 Most cases that do not respond to H pylori eradication involve the t(11;18) and t(1;14) translocations.28
Clinical presentation of gastric MALT lymphoma
The average age at presentation with gastric MALT lymphoma is 54 to 58 years.
The most common complaint is nonspecific abdominal pain in the epigastric region, sometimes accompanied by weight loss, nausea, vomiting, and, in a quarter of cases, acute or chronic bleeding.39–41 Weight loss is common, and its extent is associated with the location and the grade of the disease.
Most cases of MALT lymphoma are found serendipitously during endoscopy, on which the appearance of the lesions ranges from small ulcerations to polypoid masses with infiltrated, thickened folds involving predominantly the antrum or prepyloric region.15,41
