Lymphoproliferative Disorders of the Gastrointestinal Tract

Machine Learning Based on Morphological Features Enables Classification of Primary Intestinal T-Cell Lymphomas

The aim of this study was to investigate the feasibility of using machine learning techniques based on morphological features in classifying two subtypes of primary intestinal T-cell lymphomas (PITLs) defined according to the WHO criteria: monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) versus intestinal T-cell lymphoma, not otherwise specified (ITCL-NOS), which is considered a major challenge for pathological diagnosis. A total of 40 histopathological whole-slide images (WSIs) from 40 surgically resected PITL cases were used as the dataset for model training and testing. A deep neural network was trained to detect and segment the nuclei of lymphocytes. Quantitative nuclear morphometrics were further computed from these predicted contours. A decision-tree-based machine learning algorithm, XGBoost, was then trained to classify PITL cases into two disease subtypes using these nuclear morphometric features. The deep neural network achieved an average precision of 0.881 in the cell segmentation work. In terms of classifying MEITL versus ITCL-NOS, the XGBoost model achieved an area under receiver operating characteristic curve (AUC) of 0.966. Our research demonstrated an accurate, human-interpretable approach to using machine learning algorithms for reducing the high dimensionality of image features and classifying T cell lymphomas that present challenges in morphologic diagnosis. The quantitative nuclear morphometric features may lead to further discoveries concerning the relationship between cellular phenotype and disease status.

MALT Lymphoma of the Tongue in a Patient with Sjögren's Syndrome: A Case Report and Literature Review

Sjögren’s syndrome (SS) is a systemic chronic autoimmune disorder characterized by lymphocytic infiltration of the exocrine glands, as well as oral and ocular dryness. Among the late complications, malignant lymphoma is the most serious complication of SS. The risk of lymphoma in patients with SS has been estimated to be approximately 7–19 times higher than that in a generally healthy population. Although various histologic subtypes of lymphoma can occur in patients with SS, mucosa-associated lymphoid tissue (MALT) lymphoma accounts for 48–75% of malignant lymphomas that are frequently located in the parotid gland. However, MALT lymphoma affecting the tongue in patients with SS is extremely rare. Here, we share our experience with a unique case of MALT lymphoma of the tongue, originating from the minor salivary gland tissue in a patient with SS. Through this case report, we emphasize that MALT lymphoma should be considered in the differential diagnosis of a tongue mass in patients with SS.

Classical Hodgkin Lymphoma Presenting as a Sigmoid Mass

Primary classical Hodgkin lymphoma (CHL) in the colon is exceedingly rare and shares many histologic features with other lymphoproliferative disorders in the gastrointestinal tract. Here we report a case of CHL forming a sigmoid mass. An elderly man with a past medical history of mantle cell lymphoma presented with constipation. Imaging revealed an ulcerated, circumferential mass in the sigmoid colon. Endoscopic biopsy of the mass showed ulcerated colonic mucosa with an underlying diffuse mixed inflammatory infiltrate admixed with Hodgkin and Reed-Sternberg cells. Immunohistochemistry was performed to characterize these cells. They were weakly positive for Pax-5, strongly positive for CD30, variably positive for CD15, and negative for CD45, CD20, CD3, and SOX-11. In situ hybridization was positive for Epstein-Barr virus (EBV) and negative for cytomegalovirus or herpes simplex virus. This immunophenotype is diagnostic for CHL in the clinical context of a large mass. It is not possible in this case to determine whether this is de novo CHL or progression from a precursor lesion like EBV-positive mucocutaneous ulcer. Since diagnosis, this patient underwent colectomy followed by chemotherapy and has remained in complete remission.

Indolent T-Cell Lymphoproliferative Disorders of the Gastrointestinal Tract (iTLPD-GI): A Review

Simple Summary

This review aims to better define the clinical, pathological, and molecular features of the novel lymphoproliferative disease termed “indolent T-cell lymphoproliferative disorder of the gastro-intestinal tract (iTLPD-GI)”, to discuss potential pitfalls in differentiating this entity from other neoplastic and non-neoplastic disorders arising at the same site, and to point out a biomarker-based approach to the diagnosis.

Abstract

iTLPD-GI is a low-grade clonal T-cell lymphoproliferative disease arising in GI organs. It is an uncommon disease, and only recently has it been enlisted as a distinct provisional entity in the current WHO Classification. Data from the literature disclose high heterogeneity in terms of pathological and molecular features; on the other hand, establishing an accurate diagnosis of iTLPD-GI is of pivotal importance, since treatment options are different from that of other, more frequent lymphomas that arise in the gastrointestinal tract. In this review, we aimed to better define this novel entity, and to identify useful diagnostic biomarkers; moreover, we provide a biomarker-based approach to the diagnosis and describe the most common issues in differentiating iTLPD-GI from other neoplastic and non-neoplastic disorders.

Histologic and Cost-Benefit Analysis of Laparoscopic Sleeve Gastrectomy Specimens Performed for Morbid Obesity

CONTEXT.—

Laparoscopic sleeve gastrectomy (LSG) has quickly become the bariatric surgical procedure of choice for patients with obesity who have failed medical management. Laparoscopic sleeve gastrectomy results in a gastric remnant that is routinely subject to pathologic examination.

OBJECTIVE.—

To perform a histologic and cost-benefit analysis of gastric remnants post-LSG.

DESIGN.—

All LSG cases performed at University Health Network, Toronto, Ontario, Canada, between 2010 and 2019 were reviewed. Specimens that underwent routine histopathologic assessment and ancillary immunohistochemical analysis were analyzed. Baseline patient characteristics and surgical outcomes were obtained from our internal database. The total cost of specimen gross preparation, examination, sampling, and producing and reporting a hematoxylin-eosin slide was calculated.

RESULTS.—

A total of 572 patients underwent LSG during the study period and had their specimens examined histologically. A mean of 4.87 blocks generating 4 hematoxylin-eosin slides was produced. The most common histologic findings reported in LSG specimens ranged from no pathologic abnormalities identified together with proton pump inhibitor-related change. A minority of cases demonstrated clinically actionable histologic findings, of which Helicobacter pylori infection was the most common. The total cost for the complete pathologic analysis of these cases amounted to CaD $66 383.10 (US $47 080.21) with a mean of CaD $116.05 (US $82.40) per case. A total of CaD $62 622.75 (US $44 413.30) was spent on full examination of cases that had no further postoperative clinical impact.

CONCLUSIONS.—

There is a broad spectrum of pathologic findings in LSG specimens, ranging from clinically nonactionable to more clinically actionable. The vast majority of histologic findings had no clinical impact, with only a minority of cases being clinically significant. This study therefore recommends that LSG specimens be subject to gross pathologic examination in the vast majority of cases. However, sections should be submitted for microscopic analysis if grossly evident lesions are present and if there is a clinical/known history of clinically actionable findings.

Update on B-cell lymphoproliferative disorders of the gastrointestinal tract

The gastrointestinal (GI) tract is home to a significant portion of the immune system, which interacts daily with the antigenic milieu of its contents. Therefore, the presence of white blood cells within the walls of the GI tract upon histologic examination is a familiar sight on GI biopsies-both in health and disease. The GI tract is the most common site of extranodal lymphomas, most of which are B-cell neoplasms. Here, we review common and uncommon B-cell neoplasms of the GI tract - extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), mantle cell lymphoma, duodenal-type follicular lymphoma, diffuse large B-cell lymphoma, plasmablastic lymphoma, EBV-positive mucocutaneous ulcer, and post-transplant lymphoproliferative disorders - with special focus on literature published during the past five years. Along with the other articles in this edition of Seminars in Diagnostic Pathology, it is the authors' hope that this review proves to be a useful resource in the workup of the array of hematopoietic processes that can involve the GI tract.

Indolent T cell lymphoproliferative disorder of the gastrointestinal tract: an uncommon case with lymph node involvement and the classic Hodgkin's lymphoma

Here we describe an unusual case of an indolent CD8+ T-cell lymphoproliferative disorder in the gastrointestinal tract (ITCLD-GT) accompanied by neck lymph node infiltration and new onset of classic Hodgkin's lymphoma after two years follow-up. Previously, this 42-year-old Asian man suffered from diarrhea and abdominal pain for two years. Intestinal biopsies showed a group of small to intermediate-sized lymphocytes which were monomorphic as well as arranged in a nodular pattern with no clear boundary and were diagnosed as ITCLD-GT. He did not receive chemotherapy or have any disease progression in the gastrointestinal tract (GIT) during the follow-up until a development of neck lymphadenopathy, which led to an eventual mixed cellularity type of Hodgkin's lymphoma, one type of classic HL diagnosis. Interestingly, besides the Hodgkin's cells, the same pathological T-cells in the GIT were present in the Hodgkin's lymphoma lesions. These two pathological T cells in GIT and neck lymph node had the identical histopathological and molecular abnormalities that confirmed the abenteric distant infiltration of ITCLD-GT to the neck lymph node in this patient. This is the first case of ITCLD-GT that has a definite distant lymph node invasion. ITCLD-GT usually has a relatively good prognosis but patients with ITCLD-GT may have abenteric distant infiltration. Thus, long-term follow-up and further study of the underlying mechanisms of this process are necessary.

Indolent T cell lymphoproliferative disorder of the gastrointestinal tract: an uncommon case with lymph node involvement and the classic Hodgkin's lymphoma

Here we describe an unusual case of an indolent CD8+ T-cell lymphoproliferative disorder in the gastrointestinal tract (ITCLD-GT) accompanied by neck lymph node infiltration and new onset of classic Hodgkin's lymphoma after two years follow-up. Previously, this 42-year-old Asian man suffered from diarrhea and abdominal pain for two years. Intestinal biopsies showed a group of small to intermediate-sized lymphocytes which were monomorphic as well as arranged in a nodular pattern with no clear boundary and were diagnosed as ITCLD-GT. He did not receive chemotherapy or have any disease progression in the gastrointestinal tract (GIT) during the follow-up until a development of neck lymphadenopathy, which led to an eventual mixed cellularity type of Hodgkin's lymphoma, one type of classic HL diagnosis. Interestingly, besides the Hodgkin's cells, the same pathological T-cells in the GIT were present in the Hodgkin's lymphoma lesions. These two pathological T cells in GIT and neck lymph node had the identical histopathological and molecular abnormalities that confirmed the abenteric distant infiltration of ITCLD-GT to the neck lymph node in this patient. This is the first case of ITCLD-GT that has a definite distant lymph node invasion. ITCLD-GT usually has a relatively good prognosis but patients with ITCLD-GT may have abenteric distant infiltration. Thus, long-term follow-up and further study of the underlying mechanisms of this process are necessary.

Review of pathological findings in laparoscopic sleeve gastrectomy specimens performed for morbid obesity

BACKGROUND

Bariatric surgical procedures are employed when there is a failure of lifestyle modification in arresting obesity. Laparoscopic sleeve gastrectomy (LSG) is quickly becoming the bariatric surgical procedure of choice. LSG results in a gastric remnant that is subject to pathological examination. The objective of this paper is to review the literature in regard to histological findings identified in gastric remnants post-LSG and identify the most pertinent histological findings.

MATERIALS AND METHODS

A literature search was performed to identify relevant case series. Data gathered from relevant case series then underwent statistical analysis.

RESULTS

The most common histological findings in an LSG specimen were clinically indolent findings such as no pathological abnormalities identified followed by non-specific gastritis. A minority of cases demonstrated clinically actionable findings for which Helicobacter pylori represented the majority of these findings.

CONCLUSION

There is a broad spectrum of pathological findings in LSG specimens, ranging from clinically indolent to clinically actionable. The most common histological findings are clinically indolent and only a small portion are of clinical significance and, hence, actionable.

Practical Approach to the Histologic Diagnosis of Gastrointestinal Lymphomas Through the First-line Marker Battery of CD20, CD3, CD30, and Epstein-Barr Virus-encoded RNAs

The gastrointestinal (GI) tract is a prevalent site for extranodal lymphomas. Some subtypes of GI tract lymphomas are aggressive and have dismal clinical outcomes. Therefore, prompt histopathologic detection of such types can be very important. We thus introduce a practical approach in the histopathologic diagnosis of GI lymphomas according to the revised World Health Organization (WHO) classification. When lymphocyte proliferation is found in the GI tract, a stepwise approach can help narrow down the differential diagnoses. When considering subtype incidence, macroscopic findings, and microscopic patterns, applying a first-line marker battery of CD20, CD3, CD30, and Epstein-Barr virus-encoded RNAs can effectively narrow down the top differential diagnoses at the initial step. Generally, the most common subtype among GI tract lymphomas is B-cell non-Hodgkin lymphoma identified by CD20 expression, followed by T-cell and NK-cell non-Hodgkin lymphomas identified by the CD3 expression, and some subtypes are defined by Epstein-Barr virus infection or CD30 expression. Macroscopically, lymphomas present as various gross types, such as large masses, small lesions, superficial and shallow lesions, polyp-like or polyposis-like features, or ulcer/necrosis/perforation. Microscopically, large pleomorphic cells or small to medium-sized tumor cells grow with various architectures and tumor microenvironments. Incorporation of macroscopic and microscopic features and the stepwise immunophenotyping may be a practical approach to the differential diagnosis of aggressive lymphoma, indolent/low-grade lymphoma, or benign to indolent lymphoproliferative disease. Exceptions always exist; this approach focuses on the relatively prevalent circumstances of lymphomatous lesions initially encountered in the GI tract.

New/Revised Entities in Gastrointestinal Lymphoproliferative Disorders

The gastrointestinal tract is a common extranodal site of involvement by lymphomas. These may be diagnostically challenging because they can mimic a variety of benign conditions and may be difficult to subclassify when malignant. The classification of gastrointestinal lymphomas is an evolving area with some recent changes. Although some of these entities are rare, they are important to recognize because of the variable clinical presentations, comorbidities, and treatment implications. This article explores new and revised entities in gastrointestinal lymphoproliferative disorders.