Mucosa-associated lymphoid tissue lymphoma: multimodality imaging and histopathologic correlation. AJR Am J Roentgenol. 2010;195:W105-W117. [PMID: 20651169 DOI: 10.2214/ajr.09.4105]

Exploring virulence factors of Helicobacter pylori isolated from gastric biopsy

BACKGROUND

Helicobacter pylori (H. pylori) colonizes human gastric mucosa and is classified as class one carcinogenic bacteria. In this regard, this study aimed to detect major virulence factors in H. pylori strains recovered from gastric biopsy in patients referred to Aras Clinique in Ardabil, northwest of Iran (2019-2021).

MATERIALS AND METHODS

In this descriptive-cross sectional study, 287 dyspeptic patients were included. For bacterial isolation, gastric biopsy specimens (n=287) were taken from gastric antrum, then aseptically were cultured on the selective medium and incubated at 37C in microaerophilic conditions for 3-5 days.

RESULTS

25.18% of all (n = 70) patients were found to be infected with H. pylori upon endoscopy. Of them, 9 patients (12.857%) and 2 patients (2.875%) had peptic ulcer disease and gastric cancer respectively. According to the different patterns of virulence factors, 57 virutypes were identified in which oipA-vacAs1-vacAm2 (3, 4.28% n =) and oipA-vacAs1-vacAs2-vacAm2 (3, 4.28% n =) were the most common patterns. The simultaneous presence of vacAS2, vacAm2 and hopQ2 genes was observed in both patients with gastric cancer. OipA (n = 562.5%), VacAs1 (n = 6.75%), VacAs2 (n = 6.75%), and VacAm2 (n = 787.5%) were found to be the most prevalent virulence factor.

CONCLUSION

According previous studies, it is confirmed that the cagPAI gene cluster and vacA gene alleles are strongly correlated with gastritis and gastrointestinal tract adenocarcinomas. Our study indicated that 50% of the indigenous strains of H. pylori harbor these oncogenic genes and they are hypervirulent.

Radiological and pathological analysis of the galaxy sign in patients with pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma

BACKGROUND

Pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma sometimes presents as large pulmonary nodules composed of small nodular opacities (galaxy sign) on computed tomography (CT). The aim of this study was to assess the presence, usefulness, and pathological characteristics of the galaxy sign on CT of pulmonary MALT lymphoma.

METHODS

From January 2011 to December 2021, chest CTs of 43 patients with pulmonary MALT lymphoma were reviewed by two radiologists for the galaxy sign and various other findings. Interreader agreement to characterize the galaxy sign and factors associated in making a correct first impression on CT prior to pathological diagnosis were assessed. Resected specimens were reviewed by two pathologists, and the proportion of peripheral lymphoma infiltrates was compared between lesions with and without the galaxy sign.

RESULTS

Of 43 patients, 22 patients (44.2%) showed the galaxy sign (κ = 0.768, p < 0.0001). The galaxy sign (p = 0.010) was associated with making a correct first impression on CT prior to pathological diagnosis. On pathological examination, lesions showing the galaxy sign on CT demonstrated a significantly higher proportion of peripheral lymphoma infiltrates (p = 0.001).

CONCLUSION

The galaxy sign can be seen on CT of pulmonary MALT lymphoma with a higher proportion of peripheral lymphoma infiltrates and may be useful in making a correct diagnosis of pulmonary MALT lymphoma.

Ewing sarcoma of the ileum with wide multiorgan metastases: A case report and review of literature

BACKGROUND

Ewing sarcoma (ES) is an aggressive small round cell tumor that usually occurs in younger children and young adults but rarely in older patients. Its occurrence in elderly individuals is rare. ES of the ileum with wide multiorgan metastases is rarely reported and difficult to distinguish radiologically from other gastrointestinal tract tumors.

CASE SUMMARY

A 53-year-old man presented with right lower quadrant pain for 2 wk. Computed tomography results showed a heterogeneous mass within the ileum and widespread multiorgan metastases. This mass was biopsied, and pathological examination of the resected specimen revealed features consistent with an extraskeletal ES.

CONCLUSION

This case emphasizes the importance of recognizing this rare presentation in the small intestine to broaden the differential diagnosis of adult intraabdominal tumors.

Human Gut Microbiota-associated Gastrointestinal Malignancies: A Comprehensive Review

The human gastrointestinal tract houses trillions of microbes. The gut and various types of microorganisms, including bacteria, viruses, fungi, and archaea, form a complex ecosystem known as the gut microbiota, and the whole genome of the gut microbiota is referred to as the gut microbiome. The gut microbiota is essential for homeostasis and the overall well-being of a person and is increasingly considered an adjunct "virtual organ," with a complexity level comparable to that of the other organ systems. The gut microbiota plays an essential role in nutrition, local mucosal homeostasis, inflammation, and the mucosal immune system. An imbalanced state of the gut microbiota, known as dysbiosis, can predispose to development of various gastrointestinal malignancies through three speculated pathogenic mechanisms: (a) direct cytotoxic effects with damage to the host DNA, (b) disproportionate proinflammatory signaling inducing inflammation, and (c) activation of tumorigenic pathways or suppression of tumor-suppressing pathways. Several microorganisms, including Helicobacter pylori, Epstein-Barr virus, human papillomavirus, Mycoplasma species, Escherichia coli, and Streptococcus bovis, are associated with gastrointestinal malignancies such as esophageal adenocarcinoma, gastric adenocarcinoma, gastric mucosa-associated lymphoid tissue lymphoma, colorectal adenocarcinoma, and anal squamous cell carcinoma. Imaging plays a pivotal role in diagnosis and management of microbiota-associated gastrointestinal malignancies. Appropriate use of probiotics, fecal microbiota transplantation, and overall promotion of the healthy gut are ongoing areas of research for prevention and treatment of malignancies. Online supplemental material is available for this article. ^©RSNA, 2021.

Thymic carcinoma metastasize to the small intestine: a case report

BACKGROUND

Thymic carcinoma is a rare mediastinal neoplasm with a high malignant potential. It often shows pleural invasion and distant metastasis. The metastasis of thymic carcinoma to the small intestine is rarely reported and difficult to distinguish from other gastrointestinal tract tumors.

CASE PRESENTATION

An elderly man presented with lower abdominal pain for 2 months. Abdominal CT showed a mass communicated with the small intestinal lumen. After radical resection of the small intestinal tumor, resected specimens showed moderately differentiated squamous-cell carcinoma with lymph nodes metastases. The patient received chest CT and was found to have a mass in anterior mediastinum. Biopsies of the mass revealed thymic squamous-cell carcinoma.

CONCLUSIONS

We highlighted the metastasis of thymic carcinoma to the small intestine is rare and easily misdiagnosed. In patients with a mass communicated with the small intestinal lumen, a suspicion of thymic carcinoma metastasis should not be overlooked and we should make accurate differential diagnosis from the other small intestinal tumors.

Amyloid nodule and primary pulmonary lymphoma in the same lung: Radiologic-pathologic correlation of a rare combination

A 61-year-old man presented for lung cancer screening with low dose CT. A spiculated right apical nodule suspicious for primary lung malignancy and an indeterminate small basilar consolidation were identified. PET/CT was notable for increased FDG uptake in the basilar consolidation. Transthoracic needle biopsy of both lesions was performed which lead to pathologic diagnoses of pulmonary amyloid nodule for the apical nodule and pulmonary extramarginal zone lymphoma of the mucosa associate lymphoid tissue for the basilar consolidation. While incidental findings are common in lung cancer screening CT, exceedingly rare diagnoses or combinations or diagnoses may also be encountered. This case also underscores the value of pathologic diagnosis in cases of indeterminate lung nodules.

Gastrointestinal lymphoma: the new mimic

Background

Gastrointestinal (GI) lymphomas comprise a group of distinct clinicopathological entities of B- or T- cell type, with primary gastrointestinal Hodgkin lymphoma being extremely uncommon. The GI tract is the predominant site of extranodal non-Hodgkin lymphoma accounting for 30–40% of all extranodal lymphomas. In the Western world, the stomach is the most commonly involved site followed by the small bowel. Several chronic inflammatory and immune-mediated disorders which predispose to accelerated cell turnover may lead to the malignant transformation of gut lymphocytes and ultimately manifest as GI lymphoma. The challenge for the clinical gastroenterologist is that these tumors may have varied presentations, ranging from nonspecific symptoms such as dyspepsia or bloating to abdominal pain, nausea, vomiting, GI bleeding, diarrhea, weight loss or bowel obstruction.

Objective

We illustrate the range of presentations of GI lymphoma with examples based on consecutive cases evaluated at our institution over a 6-month period. These cases demonstrate how appropriately directed endoscopic evaluation with biopsies has the potential to provide a definitive diagnosis and allow the patient to proceed to definitive therapy.

Conclusions

The GI tract is the most commonly involved site for extranodal lymphoma with the stomach being most frequently involved organ. Chronic Helicobacter pylori infection, celiac disease, inflammatory bowel disease and autoimmune disorders may predispose to GI lymphoma. This heterogenous group of diseases has varied presentations that may mimic several other GI clinico-pathologic entities. GI lymphomas may be diagnosed with appropriately directed endoscopic evaluation coupled with generous tissue sampling and expert pathologic assessment. Management may range from antibiotic therapy, in the case of Helicobacter pylori-associated gastric MALT lymphoma, to chemotherapy with or without radiation and, in rare instances, surgery. There are presently no guidelines to direct endoscopic surveillance of GI lymphomas following treatment.

Multimodality imaging of indolent B cell lymphoma from diagnosis to transformation: what every radiologist should know

Indolent B cell lymphomas are a group of lymphoid malignancies characterized by their potential to undergo histologic transformation to aggressive lymphomas. While different subtypes of indolent B cell lymphomas demonstrate specific clinical and imaging features, histologic transformation can be suspected on cross-sectional imaging when disproportionate lymph node enlargement or new focal lesions in extranodal organs are seen. On PET/CT, transformed indolent lymphoma may show new or increased nodal FDG avidity or new FDG-avid lesions in different organs. In this article, we will (1) review the imaging features of different subtypes of indolent B cell lymphomas, (2) discuss the imaging features of histologic transformation, and (3) propose a diagnostic algorithm for transformed indolent lymphoma. The purpose of this review is to familiarize radiologists with the spectrum of clinical and imaging features of indolent B cell lymphomas and to define the role of imaging in raising concern for transformation and in guiding biopsy for confirmation.

CT, MRI, and 18F-FDG PET/CT Findings in Untreated Pulmonary and Hepatic B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue (MALT) Over a Five-Year Period: A Case Report

Imaging findings of hepatic lymphoma of mucosa-associated lymphoid tissue (MALT) have been rarely reported before. We present the computed tomography (CT), magnetic resonance imaging (MRI), and fluorine-18-fluorodeoxyglucose (F-FDG) positron emission tomography (PET)/CT findings in a patient with untreated pulmonary and hepatic MALT lymphoma over a 5-year period.On the 1st abdominal MRI scan, the hepatic MALT lymphoma showed multiple hepatic subcapsular masses. On FDG PET/CT, these hepatic tumors showed hypodenisty with FDG uptake similar to the liver on early PET images, and higher than liver on delayed PET images. The patient declined to undergo treatment. Fiver year later, the follow-up MRI and FDG PET/CT showed enlargement and confluence of the hepatic tumors with higher FDG uptake than before. The enlarged hepatic tumors had minimal mass effect. In the hepatic lesions, the blood vessels and bile ducts had no distortion or displacement.The hepatic MALT lymphoma should be taken into consideration when the hepatic tumors have minimal mass effect with the intrahepatic blood vessels and bile ducts normally passing through the tumors. Delayed-time-point FDG PET/CT imaging may be helpful for improving detectability of the hepatic MALT lymphoma.

Primary lymphomas in the gastrointestinal tract

Primary gastrointestinal (GI) lymphomas are uncommon diseases that can involve the whole GI tract. The etiologies of the disease remain unclear, and potential risk factors include celiac disease, Helicobacter pylori infection, use of immunosuppressive agents, human immunodeficiency virus (HIV) or Epstein-Barr virus (EBV) infection and inflammatory bowel disease, etc. Diffuse large B-cell lymphoma (DLBCL) and mucosa-associated lymphoid tissue (MALT) lymphoma are the most common subtypes of GI lymphomas. B-cell lymphomas of the GI tract are more common in Western countries, while in Asia-Pacific region T-cell lymphomas are more frequently reported. In this review, lymphomas in the esophagus, stomach and intestine are described, including their epidemiology, histology, clinical manifestations, endoscopic findings, radiological features and treatment.

Conjunctival MALT lymphoma: utility of FDG PET/CT for diagnosis, staging, and evaluation of treatment response

A 67-year-old woman was referred for staging of a mucosa-associated lymphoid tumor lymphoma involving the left conjunctiva. CT scan had shown paravertebral and pelvic masses, and a breast nodule. FDG PET/CT demonstrated moderately increased uptake in the left ocular conjunctiva and confirmed the paravertebral and pelvic masses and the breast nodule. Moreover, abnormal FDG uptake was shown in 2 breast nodules, the flank, the gluteus maximus, and the gastric cardia. The patient received 6 cycles of rituximab-bendamustine chemotherapy with a complete clinical and metabolic response at the 6-month follow-up PET/CT and remained relapse-free without visual acuity problem after a 36-month follow-up.

Imaging of primary gastrointestinal lymphoma

Primary gastrointestinal (GI) lymphoma most often arises from stomach, small bowel, or colon. The 2 most common subtypes of primary GI lymphoma include low-grade mucosa-associated lymphoid tissue lymphoma, strongly associated with Helicobacter pylori infection, and high-grade diffuse, large B-cell lymphoma. Primary GI lymphoma demonstrates a myriad of imaging manifestations that can commonly mimic other pathologies. Timely and accurate diagnosis remains important because treatment and prognosis of primary GI lymphoma differ significantly from other GI malignancies and even lymphoma of other primary sites.

Role of Helicobacter pylori in gastric mucosa-associated lymphoid tissue lymphomas

Mucosa-associated lymphoid tissue (MALT) lymphoma is an indolent extranodal marginal zone B-cell lymphoma, originating in acquired MALT that is induced in mucosal barriers as part of a normal adaptive immune response to a chronic immunoinflammatory stimulus, most notably chronic infection by Helicobacter pylori (H. pylori). This antigenic stimulation initially leads to lymphoid hyperplasia; the acquisition of additional genetic aberrations culminates in the activation of intracellular survival pathways, with disease progression due to proliferation and resistance to apoptosis, and the emergence of a malignant clone. There are descriptions of MALT lymphomas affecting practically every organ and system, with a marked geographic variability partially attributable to the epidemiology of the underlying risk factors; nevertheless, the digestive system (and predominantly the stomach) is the most frequently involved location, reflecting the gastrointestinal tract’s unique characteristics of contact with foreign antigens, high mucosal permeability, large extension and intrinsic lymphoid system. While early-stage gastric MALT lymphoma can frequently regress after the therapeutic reversal of the chronic immune stimulus through antibiotic eradication of H. pylori infection, the presence of immortalizing genetic abnormalities, of advanced disease or of eradication-refractoriness requires a more aggressive approach which is, presently, not consensual. The fact that MALT lymphomas are rare neoplasms, with a worldwide incidence of 1-1.5 cases per 10⁵ population, per year, limits the ease of accrual of representative series of patients for robust clinical trials that could sustain informed evidence-based therapeutic decisions to optimize the quality of patient care.

Primary malt lymphoma of the common bile duct

Primary mucosa-associated lymphoid tissue (MALT) lymphoma arising in the common bile duct (CBD) is extremely rare. In our case of MALT lymphoma, CT and MRI showed long, segmental, irregular wall thickening of the CBD and minimal dilatation of the upstream bile duct. A preoperative diagnosis of cholangiocarcinoma was made, but histologic evaluation confirmed MALT lymphoma of the CBD. We herein present a rare case of MALT lymphoma of the CBD with CT and MRI findings.