Low-grade gastric mucosa-associated lymphoid tissue lymphoma: correlation of radiographic and pathologic findings

From the radiologic pathology archives: gastrointestinal lymphoma: radiologic and pathologic findings

Gastrointestinal (GI) lymphoma encompasses a heterogeneous group of neoplasms that have a common lymphoid origin but variable pathologic and imaging features. Extranodal marginal zone B-cell lymphoma (ENMZL) and diffuse large B-cell lymphoma (DLBCL) are the most common. ENMZL usually occurs in the stomach, where it is associated with chronic infection by Helicobacter pylori, and is typically a superficial spreading lesion that causes mucosal nodularity or ulceration and mild wall thickening. DLBCL may arise de novo or from transformation of ENMZL or other low-grade lymphomas. This form of lymphoma produces extensive wall thickening or a bulky mass, but obstruction is uncommon. Mantle cell lymphoma is the classic cause of lymphomatous polyposis, but multiple polyps or nodules can also be seen with ENMZL and follicular lymphoma. Burkitt lymphoma is usually characterized by an ileocecal mass or wall thickening in the terminal ileum in young children, often in the setting of widespread disease. Primary GI Hodgkin lymphoma, which is rare, may be manifested by a variety of findings, though stenosis is more common than with non-Hodgkin lymphoma. Enteropathy-associated T-cell lymphoma is frequently associated with celiac disease and is characterized by wall thickening, ulceration, and even perforation of the jejunum. Accurate radiologic diagnosis of GI lymphoma requires a multifactorial approach based on the clinical findings, site of involvement, imaging findings, and associated complications.

Imaging of gastrointestinal lymphoma

The gastrointestinal (GI) tract contains the largest collection of lymphocytes anywhere in the body. GI lymphoma may arise at any site in the GI tract but typically involves the stomach and small bowel in cases of systemic disease. Most cases are non-Hodgkin B-cell type. Enteropathy-associated T cell lymphoma can complicate celiac disease. Less commonly, lymphoma may originate in the GI tract without systemic involvement. This sometimes occurs in response to chronic infections. This article discusses the role of imaging in detecting and staging GI tract lymphomas, using fluoroscopy and cross-sectional imaging, primarily CT.

Hodgkin's and Non-Hodgkin's Lymphomas

The diagnosis and management of lymphoma have undergone significant changes in the past 20 years. For example, new immunophenotypic and molecular methods have replaced traditional histology-based classification schemes for lymphoma. Fluorine-18-deoxyglucose (FDG) positron emission tomography (PET) has evolved into a potent staging tool and prognostic indicator in many kinds of lymphoma. The role of radiation therapy, especially in patients who have early-stage Hodgkin's disease, has changed substantially. The introduction of anti-CD 20 antibody therapy (Rituximab) has improved the treatment of B-cell lymphoma. These changes are linked with higher expectations for imaging, such as detection of more subtle lymphoma manifestations, evaluation of residual changes, and better assessment of early response. This article reviews clinical and radiologic features of both Hodgkin's disease and non-Hodgkin's lymphoma. It also describes the radiologic staging of lymphoma and the emerging role of FDG-PET for assessing lymphoma.

Primary gastrointestinal lymphomas: A radiological-pathological review. Part 1: Stomach, oesophagus and colon

Primary gastrointestinal lymphomas are most common in the stomach, followed by small intestine and then colon. The most frequently used pathology classification of lymphomas is the Revised European and American Lymphoma /World Health Organization classification. The correlation of radiological morphology with histology is relatively poor, although characteristic subtypes will be discussed. In the stomach, the majority of primary lymphomas are of B-cell origin of mucosa-associated lymphoid tissue (MALT) type. Low-grade MALT lymphomas are associated with Helicobacter pylori infection and often respond to eradication of this organism. Radiological features include thickened folds, nodularity, depressed lesions, ulcers, prominent areae gastricae. High-grade (large B-cell) tumour patterns include infiltrative, polypoid, nodular, ulcerated or a combination. Endoscopy, endoscopic ultrasound and CT are important in diagnosis and staging, although appearances on barium studies should be recognized. Primary colonic lymphomas are rare. Most are of B-cell origin. Focal and diffuse forms are seen, the former producing polypoid or nodular or cavitating masses and the latter producing ulcerative or nodular (polyposis) patterns on imaging. Even when circumferential, lymphoma rarely causes obstruction. Small bowel lymphomas will be discussed in the forthcoming part 2 of this review.

Gastric mucosa-associated lymphoid tissue lymphoma

The connection between Helicobacter pylori and gastric mucosa-associated lymphoid tissue (MALT) lymphoma is well established. H. pylori infection causes an immunological response, leading to chronic gastritis with formation of lymphoid follicles within the stomach. These lymphoid follicles resemble nodal tissues found throughout the body and are composed of reactive T cells and activated plasmal cells and B cells. The B cells are responsible for initiating a clonal expansion of centrocyte-like cells that form the basic histology of MALT lymphoma. Early diagnosis of MALT lymphoma is difficult but essential for adequate treatment. Clinical symptoms are vague and varied, with abdominal pain being a common presenting complaint. The endoscopic appearance of this tumor is varied and can be infiltrative, exophytic, or ulcerative. In addition, the tumor can have a multifocal distribution, and therefore aggressive tissue sampling is crucial for diagnosis. Endoscopic ultrasound is essential to document the extent of disease and is more accurate than CT scan in detection of spread to perigastric lymph nodes. Lesions that are confined to the mucosa or submucosa of the gastric wall are believed to be dependent on H. pylori stimulation and therefore can be successfully treated with H. pylori eradication. Those MALT lymphomas that present at more advanced stages require more aggressive management and can be treated with surgical resection, radiation, or chemotherapy. Follow-up is critical in all patients who have been treated with H. pylori eradication and consists of multiple endoscopic biopsies for histological and molecular studies as well as endoscopic ultrasound at 3, 6, and 12 months after treatment. The reappearance of MALT lymphomas has been seen years after treatment, and therefore follow-up of these patients should be indefinite.

Radiographic findings of primary B-cell lymphoma of the stomach: low-grade versus high-grade malignancy in relation to the mucosa-associated lymphoid tissue concept

OBJECTIVE

We undertook this study to assess how well double-contrast radiography and CT allow radiologists to differentiate low-grade from high-grade mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach.

MATERIALS AND METHODS

We retrospectively reviewed the upper gastrointestinal radiographs and contrast-enhanced CT scans of 57 patients with pathologically proven primary gastric lymphoma (low-grade [n = 29] and high-grade [n = 28] MALT lymphoma).

RESULTS

On upper gastrointestinal radiography, ulceration (39%) was the most common finding in low-grade lymphoma, whereas polypoid appearance (38%) was the most common in high-grade lymphoma. In the 29 patients (33 lesions) with low-grade MALT lymphoma, upper gastrointestinal radiography revealed 13 ulcerative lesions (39%), 10 nodular lesions (30%), four infiltrative lesions (12%), two polypoid lesions (6%), and four combined lesions (12%). In the 28 patients (29 lesions) with high-grade lymphoma, upper gastrointestinal radiography revealed 11 polypoid lesions (38%), nine infiltrative lesions (31%), six ulcerative lesions (20%), one nodular lesion (3%), and two combined lesions (7%). On CT, thickening of the gastric wall in low-grade lymphoma (range, 0.3-2.5 cm; mean, 0.8 cm) was much less than that in high-grade lymphoma (range, 0.7-8.0 cm; mean, 2.5 cm). Abdominal lymphadenopathy was less frequent in low-grade lymphoma (14%) than in high-grade lymphoma (75%).

CONCLUSION

Most low-grade lymphomas show superficial spreading lesions, such as mucosal nodularity, shallow ulcer, and minimal fold thickening, on upper gastrointestinal radiography, whereas most high-grade lymphomas show mass-forming lesions or severe fold thickening.

Gastric mucosa-associated lymphoid tissue lymphoma: helical CT findings and pathologic correlation

OBJECTIVE

The purpose of this study was to describe helical CT findings of gastric mucosa-associated lymphoid tissue (MALT) lymphoma and to correlate them with pathologic findings.

MATERIALS AND METHODS

We retrospectively reviewed CT examinations of 58 patients with confirmed gastric MALT lymphomas. Using the histopathologic grade of the MALT lymphomas, we divided the patients into two groups: those with high-grade lymphoma (n = 21) and those with low-grade lymphoma (n = 37). Common CT findings for the two groups were reviewed and compared.

RESULTS

Forty (69%) of the 58 patients showed at least one abnormality of the stomach on CT. Abnormalities included diffuse or segmental gastric wall thickening (66%, 38/58), lymphadenopathy (40%, 23/58), ulcer (22%, 13/58), and gastric mass (3%, 2/58). Eighteen (31%) of 58 patients were found to have no abnormality. The high-grade group had a higher incidence of abnormalities seen on CT than the low-grade group (100% vs 51%, respectively). Gastric wall thickening in the high-grade group was more diffuse (48% vs 8%) and severe (71% vs 14%; severe or moderate) than that seen in the low-grade group. Lymphadenopathy was visualized in 67% of the high-grade group and in 24% of the low-grade group. Gastric ulcer was found in 57% of the high-grade group and in only 5% of the low-grade group. The gastric mass formation was seen in only two patients in the high-grade group.

CONCLUSION

The CT findings of gastric MALT lymphoma that the two groups had in common were gastric wall thickening and lymphadenopathy. Although our results pointed to no specific CT finding for differentiating high-grade from low-grade gastric MALT lymphomas, we found that the absence of abnormality on CT is highly predictive of low-grade MALT lymphoma.

Gastric mucosa-associated lymphoid tissue lymphoma: spectrum of findings at double-contrast gastrointestinal examination with pathologic correlation

Mucosa-associated lymphoid tissue (MALT) is found in the surface epithelium of the stomach. MALT lymphoma is extranodal lymphoma originating from MALT. In the stomach, a strong association with Helicobacter pylori infection has been demonstrated. Low-grade gastric MALT lymphoma has been reported to have variable features at upper gastrointestinal (UGI) examination. Twenty-two patients with low-grade MALT lymphoma had ulcers (n = 11), fold thickening (n = 7), mucosal nodularity (n = 7), masses (n = 6), or prominent areae gastricae (n = 4) at UGI examination. Six patients with high-grade MALT lymphoma had masses (n = 4), fold thickening (n = 3), ulcers (n = 1), or mucosal nodularity (n = 1) at UGI examination. These findings were similar to those in gastric carcinoma or gastritis. Differentiation of low-grade MALT lymphoma from gastritis or gastric carcinoma was more difficult than differentiation of high-grade MALT lymphoma. Lesions of MALT lymphoma associated with H pylori gastritis were diffuse or multiple in 65% of cases; however, lesions of MALT lymphoma without proved H pylori gastritis were focal or solitary in 80% of cases. Therefore, multiplicity of lesions in MALT lymphoma was closely associated with H pylori infection.