Primary follicular lymphoma of the small intestine: alpha4beta7 expression and immunoglobulin configuration suggest an origin from local antigen-experienced B cells

The 2008 WHO classification of lymphomas: implications for clinical practice and translational research

The 4(th) edition of the WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues published in 2008 builds upon the success of the 2001 3(rd) edition; new entities are defined, and solutions for problematic categories are sought. Recent studies have drawn attention to the biological overlap between classical Hodgkin lymphoma (CHL) and diffuse large B-cell lymphomas (DLBCL). Similarly, there is a greater appreciation of the borderlands between Burkitt lymphoma and DLBCL. Strategies for the management of these borderline lesions are proposed. Additionally, age-specific and site-specific factors play an important role in the definition of several new entities, which also have biological underpinnings. Among the peripheral T-cell lymphomas (PTCL), more precise definitions were introduced for several entities, including anaplastic large cell lymphoma, angioimmunoblastic T-cell lymphoma, enteropathy-associated T-cell lymphoma, and subcutaneous panniculitis-like T-cell lymphoma. Several new variants of primary cutaneous T-cell lymphomas are proposed. Finally, the subclassification and categorization of the most common lymphoma subtypes, follicular lymphoma (FL) and DLBCL, were altered to enhance diagnostic accuracy and aid in clinical management. The 2008 WHO classification also draws attention to early events in lymphomagenesis. These lesions help delineate the earliest steps in neoplastic transformation and generally mandate a conservative therapeutic approach. The 2001 classification was rapidly adopted for clinical trials and successfully served as a common language for scientists comparing genetic and functional data. The modifications made in the 2008 classification are the result of this successful partnership among pathologists, clinicians, and biologists, but are only a stepping stone to the future.

The 2008 WHO classification of lymphomas: implications for clinical practice and translational research

The 4th edition of the WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues published in 2008 builds upon the success of the 2001 3rd edition; new entities are defined, and solutions for problematic categories are sought. Recent studies have drawn attention to the biological overlap between classical Hodgkin lymphoma (CHL) and diffuse large B-cell lymphomas (DLBCL). Similarly, there is a greater appreciation of the borderlands between Burkitt lymphoma and DLBCL. Strategies for the management of these borderline lesions are proposed. Additionally, age-specific and site-specific factors play an important role in the definition of several new entities, which also have biological underpinnings. Among the peripheral T-cell lymphomas (PTCL), more precise definitions were introduced for several entities, including anaplastic large cell lymphoma, angioimmunoblastic T-cell lymphoma, enteropathy-associated T-cell lymphoma, and subcutaneous panniculitis-like T-cell lymphoma. Several new variants of primary cutaneous T-cell lymphomas are proposed. Finally, the subclassification and categorization of the most common lymphoma subtypes, follicular lymphoma (FL) and DLBCL, were altered to enhance diagnostic accuracy and aid in clinical management. The 2008 WHO classification also draws attention to early events in lymphomagenesis. These lesions help delineate the earliest steps in neoplastic transformation and generally mandate a conservative therapeutic approach. The 2001 classification was rapidly adopted for clinical trials and successfully served as a common language for scientists comparing genetic and functional data. The modifications made in the 2008 classification are the result of this successful partnership among pathologists, clinicians, and biologists, but are only a stepping stone to the future.

The majority of cutaneous marginal zone B-cell lymphomas expresses class-switched immunoglobulins and develops in a T-helper type 2 inflammatory environment

Extranodal marginal zone B-cell lymphomas (MZBCLs) arise on a background of chronic inflammation resulting from organ-specific autoimmunity, infection, or by unknown causes. Well-known examples are salivary gland MZBCL in Sjögren's sialadenitis and gastric MZBCL in Helicobacter pylori gastritis. MZBCLs express CXCR3, a receptor for interferon-γ–induced chemokines highly expressed in the chronic inflammatory environment. The immunoglobulin (Ig) variable heavy/light chain (IgVH/IgVL) gene repertoire of salivary gland and gastric MZBCL appears restricted and frequently encodes B-cell receptors with rheumatoid factor reactivity. Primary cutaneous marginal zone B-cell lymphomas (PCMZLs) are regarded as the skin-involving counterparts of extranodal MZBCLs. Although PCMZLs have been associated with Borrelia burgdorferi dermatitis, PCMZLs generally arise because of unknown causes. We studied an extensive panel of PCMZLs and show that PCMZLs do not conform to the general profile of extranodal MZBCL. Whereas most noncutaneous MZBCLs express IgM, PCMZLs in majority express IgG, IgA, and IgE and do not show an obvious immunoglobulin repertoire bias. Furthermore, the isotype-switched PCMZLs lack CXCR3 and seem to arise in a different inflammatory environment, compared with other extranodal MZBCLs.

Primary gastrointestinal follicular lymphoma: a clinicopathologic study of 13 cases from Taiwan

GOALS

Follicular lymphoma (FL) is a common nodal lymphoma. Primary gastrointestinal follicular lymphoma (GIFL) is rare and most commonly occurs in the elder women with indolent clinical course, mainly in the duodenum and terminal ileum. We conducted this study to characterize GIFL in Taiwan.

STUDY

A total of 13 cases were retrospectively collected in 4 hospitals in southern and eastern Taiwan up to 2006. Pathology review and immunohistochemistry were performed and the clinical data were obtained from chart review.

RESULTS

There were 5 men and 8 women with a median age of 58 years (range, 31 to 74; mean, 55). The most frequent site was ileum (7/13, 54%) with 4 tumors in the terminal ileum and the most common symptom was abdominal pain (8/13, 62%). Multiple lymphomatous polyposis was present in 6 patients (46%). Five (45%) of 11 tumors with surgical resection showed transmural involvement. Most of the cases revealed a predominantly follicular pattern (7/13, 54%) and low-grade disease (grades 1 and 2; 10/13, 77%). The tumors expressed CD10 (62%), Bcl-2 (77%), Bcl-6 (77%), and MUM1 (38%). Five patients (38%) were at stage IE and 8 (62%) at stage IIE. Treatment included surgery with or without chemotherapy. All patients achieved complete remission and relapse occurred in 3 patients. At a median follow-up time of 51 months (range, 3 to 180; mean, 63), 11 patients (85%) were disease free and no patient died of lymphoma.

CONCLUSIONS

We characterized the clinicopathologic features of the first series of GIFL in Taiwan. These tumors frequently involved ileum with a favorable prognosis.

Extranodal lymphoma

Lymphomas arising in extranodal sites are intriguing. The types of lymphomas encountered vary widely from one extranodal site to another. For many types of extranodal lymphomas, there are distinctive clinicopathologic features, sometimes including association with an underlying immunodeficiency syndrome, autoimmune disease, infection, or other immunologic disorder, or a predilection to affect patients of certain ethnic origins. Presented below is a review of lymphomas that are encountered most often in extranodal sites.

Primary duodenal follicular lymphoma successfully treated with rituximab

Non-Hodgkin's lymphoma (NHL) of the gastrointestinal (GI) tract is the most common extranodal lymphoma, accounting for approximately 40% of all extranodal NHLs. Initial treatment of duodenal lymphoma includes surgery, chemotherapy and radiotherapy, alone or in combination. Here, we present a case of stage I primary duodenal follicular lymphoma (FL) showing a complete response after rituximab therapy. Rituximab alone can be an effective alternative treatment for duodenal FL.

Primary small-bowel non-Hodgkin's lymphoma: a study of clinical features, pathology, management and prognosis

The records of 34 patients diagnosed with primary small bowel non-Hodgkin's lymphoma during a 10-year period between January 1996 and December 2005, including 27 cases for which complete follow-up records were available, were studied. Abdominal pain (70.6% of patients) was the main presenting symptom, followed by intestinal obstruction (38.2%). The most common primary site was the ileum (58.8%), followed by the jejunum (26.5%) and duodenum (17.6%); one case had tumours at two sites in the small bowel. Twenty-seven patients had small bowel B-cell lymphoma (24 diffuse large B-cell lymphoma; three mucosa-associated lymphoid tissue B-cell lymphoma) and seven patients had small bowel T-cell lymphoma. Cumulative survival in patients with small bowel B-cell lymphoma was higher than that in patients with small bowel T-cell lymphoma. Data on 16 male and eight female patients with diffuse large B-cell lymphoma showed that 62.5% of these patients presented with disease stages I or II and 37.5% with stages III or IV. Cumulative survival in patients at stages IE or IIE was significantly higher than that of patients at stages IIIE or IVE. Four of five patients who died from diffuse large B-cell lymphoma had abnormal levels of lactate dehydrogenase and serum albumin.

Primary adrenal adult T-cell leukemia/lymphoma: a case report and review of the literature

Primary adrenal lymphoma (PAL) is very rare; the majority of cases reported previously were of B-cell origin. We report a rare case of primary adrenal adult T-cell leukemia/lymphoma (primary adrenal ATLL). ATLL is a highly aggressive T-cell type non-Hodgkin's lymphoma and etiologically associated with human T-cell lymphotropic virus 1 (HTLV-1). Most ATLL patients present with leukemia and widespread lymphadenopathy. A 37-year-old Japanese woman presented with back pain in January 2004. Examination showed no peripheral lymphadenopathy, circulating lymphoma cells, hepatosplenomegaly, and skin lesions. Imaging studies demonstrated large adrenal masses bilaterally. Subsequently, she underwent open adrenal biopsy and pathological diagnosis was confirmed as T-cell lymphoma. The serum antibody to HTLV-1 was positive. Southern blot analysis detected monoclonal integration of proviral DNA of HTLV-1 into host genome in the biopsy specimen. The diagnosis of ATLL arising in adrenal glands was established. Despite repeated systemic chemotherapy, the patient died of progressive disease in December 2004. ATLL could primarily involve the adrenal gland and this disease entity should be included in the differential diagnosis of adrenal mass lesions.

Lymphoma dissemination: the other face of lymphocyte homing

The orchestration of systemic immune responses is critically dependent on coordinated lymphocyte migration and recirculation. This "homing" guides lymphocytes to the microenvironments that control their differentiation and survival, disperses the immunologic repertoire, and targets effector lymphocytes to sites of antigenic insult. Lymphocyte homing is a multistep process that requires chemotaxis and cell adhesion coupled with strategies to overcome physical barriers. At the molecular level, it is regulated by adhesion molecules and chemokines, and facilitated by intrinsic molecular programs that allow "ameboid" shape change, allowing highly effective lymphocyte traffic between different tissue compartments. In case of malignant transformation, however, the fact that lymphocytes are "licensed to move" forms a serious threat to the organism, because it permits rapid tumor dissemination irrespective of the conventional anatomic boundaries limiting early spread in most types of cancer. Thus, unlike the metastatic spread of other cancers, lymphoma dissemination generally is not a reflection of tumor progression but of conserved physiological behavior. The dissemination patterns often reflect basic rules of lymphocyte homing, explaining the strikingly tissue-specific dissemination of, for example, mucosal lymphomas, cutaneous lymphomas, and multiple myeloma. Understanding the molecular mechanisms underlying this behavior may provide novel targets for treatment of lymphoma patients.

Primary Follicular Lymphoma of the Testis and Epididymis in Adults

Primary testicular lymphomas typically occur in patients over 60 years of age. Most are diffuse large B-cell lymphomas with frequent dissemination and a poor prognosis. Primary follicular lymphoma of the adult testis has not been well characterized. However, a small number of primary testicular follicular lymphomas have recently been described in children. These showed stage 1E disease, a lack of BCL2 gene rearrangement and Bcl-2 protein expression, and a good clinical outcome. Here, we describe 5 cases of primary follicular lymphoma of the testis and epididymis in adults. These presented as unilateral testicular masses 12 to 40 mm in diameter and were characterized histologically by small neoplastic follicles in a sclerotic background. The neoplastic cells expressed CD10 and Bcl-6, but not Bcl-2 and lacked t(14;18)(q32;q21)/IGH-BCL2 and BCL6 gene rearrangements. Four of the five patients were 35 years old or younger, and 4 presented with stage 1EA disease. Although follow-up is 12 months or less in 2 of the 5 patients, to date each has followed an indolent clinical course. These features are different from those of most adult nodal follicular lymphomas but are very similar to those of the pediatric primary testicular follicular lymphomas. Together, the pediatric and adult cases represent a discrete clinicopathologic entity of t(14;18)(q32;q21)/IGH-BCL2-negative primary follicular lymphoma of the testis and epididymis, which typically present as clinically indolent localized disease in young males and should be distinguished from the diffuse large B-cell lymphoma more frequently seen in the testes of older adults.

Small follicular lymphoma arising near the ampulla of vater: a distinct subtype of duodenal lymphoma?

A 49-yr-old Japanese woman underwent upper gastrointestinal endoscopy because of nonspecific dyspepsia. Endoscopy revealed a flat elevated lesion about 15 mm in diameter adjacent to the duodenal papilla, the surface of which was uneven and covered with whitish granules. Based on the results of histological examination with immunohistochemistry (positive for CD10, CD20, CD79a, and bcl-2 protein, negative for CD5 and cyclin D1), a diagnosis of grade 1/3 follicular lymphoma was established. Systemic staging examinations suggested the lymphoma was restricted to the mucosa and superficial portion of the submucosa in the duodenal wall. The patient was treated with a combination of CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisolone) and monoclonal anti-CD20 antibody (rituximab), in addition to radiotherapy. After six courses of this combination chemotherapy, complete regression of the lymphoma was observed. Although reports of small duodenal lymphoma (<20 mm or localized to the mucosa or submucosa) are extremely rare, the features of this case are characteristic of small duodenal lymphoma in terms of evolution around the ampulla of Vater, low-grade follicular type, occurrence in a women, occurrence in the fourth decade of life, and favorable outcome, and this type of tumor may need to be distinguished by pathogenesis and clinical behavior from various other gastrointestinal lymphomas.

Small Lymphoid Proliferations in Extranodal Locations

Context.—Low-grade non-Hodgkin lymphomas frequently involve extranodal sites including the gastrointestinal tract, skin, and lung, either selectively or as part of widespread dissemination. Differentiation from inflammatory or infectious conditions requires knowledge of specific histologic characteristics of the various entities as well as ancillary techniques.

Objective.—To describe the key features and provide diagnostic clues to the identification of specific extranodal low-grade lymphomas of T-cell and B-cell types including small lymphocytic lymphoma, follicular lymphoma, mantle cell lymphoma, extranodal marginal zone B-cell lymphomas of mucosal-associated lymphoid tissue, and hairy cell leukemia. Histologic and cytologic features are highlighted, as well as appropriate integration of results of ancillary diagnostic studies including flow cytometry, immunohistochemistry, molecular features, and cytogenetics.

Data Sources.—The published literature as well as personal experience from a specialized hematopathology practice at a large university medical center.

Conclusions.—Correct identification of extranodal low-grade lymphomas and differentiation from hyperplastic and inflammatory or infectious processes require the ability to distinguish each of the specific entities discussed. Ancillary studies are often indispensable in reaching a correct diagnosis.

Molecular pathways in follicular lymphoma

Follicular lymphoma (FL) is one of the most common B-cell non-Hodgkin's lymphomas. The initiating genetic event found in approximately 90% of FL is the t(14;18), causing constitutive expression of the antiapoptotic BCL-2 protein. The exact secondary alterations leading to full FL development are still poorly defined. In this review, we address (i) the genetic pathways associated with tumorigenesis and progression of FL, (ii) the role of micro-environmental factors with emphasis on B-cell receptor ligands and (iii) lymphoma models in mice and what they teach us about lymphomagenesis in man.

BCL2 gene abnormalities define distinct clinical subsets of follicular lymphoma

AIMS

Follicular lymphoma (FL) arising primarily in the skin has recently been proposed as a distinct entity on the basis of a low incidence of t(14;18)(q32;q21) and bcl-2 expression, with a very high percentage of patients surviving more than 5 years. However, cases of t(14;18)(q32;q21)-positive primary cutaneous FL (PCFL) and examples of t(14;18)(q32;q21)-negative FL at nodal and other extranodal sites, are well documented. The aim of this study was to test the hypothesis that there is a subtype of FL lacking t(14;18)(q32;q21), which preferentially involves certain sites but is not restricted by anatomical location.

METHODS AND RESULTS

A cohort of 47 stage 1 FL was stratified according to the presence or absence of t(14;18)(q32;q21) using conventional cytogenetics, polymerase chain reaction and interphase fluorescence in situ hybridization. Compared with t(14;18)(q32;q21)-positive cases, FL lacking the translocation were less likely to express CD10 or bcl-2 (P<0.01), made up a significantly greater proportion of cases arising at extranodal sites (P<0.001) and had a significantly better overall and disease-specific 5-year survival (P<0.01).

CONCLUSIONS

These results support the concept of a subtype of FL lacking t(14;18)(q32;q21), characterized by low-intensity bcl-2 expression, a predilection for extranodal sites, particularly the skin, and a more favourable outcome than t(14;18)(q32;q21)-positive FL.

Proteomic Analysis of Apoptotic Pathways Reveals Prognostic Factors in Follicular Lymphoma

Follicular lymphoma (FL) is the second most common non-Hodgkin's lymphoma and generally is incurable. Reliable prognostic markers to differentiate patients who progress rapidly from those who survive for years with indolent disease have not been established. Most cases overexpress Bcl-2, but the pathogenesis of FL remains incompletely understood. To determine whether a proteomic approach could help overcome these obstacles, we procured lymphoid follicles from 20 cases of FL and 15 cases of benign follicular hyperplasia (FH) using laser capture microdissection. Lysates were spotted on reverse-phase protein microarrays and probed with 21 antibodies to proteins in the intrinsic apoptotic pathway, including those specific for posttranslational modifications such as phosphorylation. A panel of three antibodies [phospho-Akt(Ser473), Bcl-2, and cleaved poly(ADP-ribose) polymerase] segregated most cases of FL from FH. Phospho-Akt(Ser473) and Bcl-2 were significantly increased in FL (P = 0.001 and P < 0.0001, respectively). Additionally, the Bcl-2/Bak ratio completely segregated FL from FH. High ratios of Bcl-2/Bak and Bcl-2/Bax were associated with early death from disease with differences in median survival times of 7.3 years (P = 0.0085) and 3.8 years (P = 0.018), respectively. Using protein microarrays, we identified candidate proteins that may signify clinically relevant molecular events in FL. This approach showed significant changes at the posttranslational level, including Akt phosphorylation, and suggested new prognostic markers, including the Bcl-2/Bak and Bcl-2/Bax ratios. Proteomic end points should be incorporated in larger, multicenter trials to validate the clinical utility of these protein microarray findings.

One patient, two lymphomas. Simultaneous primary gastric marginal zone lymphoma and primary duodenal follicular lymphoma

We report the case of a 73-year-old man who presented with a 2- to 3-month history of epigastric discomfort and guaiac-positive stool. An upper gastrointestinal endoscopy revealed a diffuse erythematous nodular mucosa and submucosal thickening in the stomach. Diffuse mucosal nodularity was also found in the second portion of the duodenum. A complete workup with histologic, immunohistochemical, and molecular studies revealed 2 distinct, apparently unrelated lymphomas, namely, a gastric marginal zone B-cell lymphoma (mucosa-associated lymphoid tissue type) in a background of Helicobacter pylori gastritis and a grade 1/3 duodenal follicular lymphoma. The patient was then treated with an H pylori eradication regimen. No therapy was given for his duodenal follicular lymphoma because his symptoms were thought to be due to the gastric disease and because the duodenal lesion was small. A 6-month follow-up with upper gastrointestinal endoscopy revealed only focal biopsy scarring in the stomach and an apparently normal duodenum. The follow-up biopsies revealed significant regression of his mucosa-associated lymphoid tissue lymphoma, but persistence of his duodenal follicular lymphoma. The combination of these 2 lymphomas in the same patient and the different clinical responses to antibiotic treatment make this case unique.

Adult T-cell leukemia predominantly involving exocrine glands

OBJECTIVES

We describe a rare case of adult T-cell leukemia (ATL) presenting with dry mouth and swelling of bilateral parotid and submandibular glands. The unusual involvement of these exocrine glands by malignant cells prompted us to conduct a detail characterization of these infiltrating and circulating leukemic T cells, which may provide insight to the pathogenesis of exocrine involvement in ATL.

METHODS

Immunophenotyping of peripheral ATL cells and microscopic examinations of various organs prepared by autopsy were performed. Analysis of the repertoire of T-cell receptor (TCR) of parotid gland-infiltrating ATL cells using molecular and immunohistochemical examinations were also performed.

RESULTS

Microscopic examinations of various organs prepared by autopsy revealed the predominant and specific exocrine gland infiltration of ATL cells. Reverse transcription-polymerase chain reaction (RT-PCR) followed by both TCR spectratyping and complementary determining region (CDR)-3 sequencing analysis of TCR Vbeta of parotid gland-infiltrating T cells revealed a relatively restricted but not single usage of TCR Vbeta. Immunohistochemical analyses of parotid gland specimens detected only a small number of TCR Valphabeta-positive cells in parotid gland-infiltrating ATL cells.

CONCLUSIONS

The predominant infiltration of ATL cells in exocrine glands implied that these T cells recognized exocrine gland-specific antigen. However, the absence of both TCR Vbeta mRNA transcripts and TCR Valphabeta protein expression in most ATL cells suggested that antigen recognition via TCR may not have played a major role in adhesion and subsequent infiltration into the exocrine glands in this patient. These results provide important background information to further elucidate the pathogenesis of exocrine gland-specific inflammation.

Extranodal follicular lymphoma: a clinicopathological and genetic analysis of 15 cases arising at non-cutaneous extranodal sites

AIMS

Recent studies of primary cutaneous follicular lymphoma suggest that it represents a clinicopathological entity distinct from nodal follicular lymphoma (FL). The purpose of this study was to determine if FL arising at other extranodal sites is more closely related to FL occurring in the skin or in lymph nodes.

METHODS AND RESULTS

Fifteen cases of non-cutaneous extranodal follicular lymphoma (ENFL) were identified from the Scotland and Newcastle Lymphoma Group (SNLG) database. All were stage 1E at presentation and involved the tonsil (n = 3), palate (n = 3), skeletal muscle (n = 2), ileum (n = 2), duodenum (n = 1), stomach (n = 1), thyroid gland (n = 1), submandibular gland (n = 1) and fallopian tube (n = 1). Polymerase chain reaction for t(14;18) using primers to the major breakpoint cluster region was performed on 14 cases of ENFL and the incidence of the translocation compared with that found in 16 cases of stage 1 nodal FL. Clinical and follow-up data were obtained from the SNLG database for the 15 cases of ENFL and 87 cases of stage 1 nodal FL, and a comparison of outcomes made. Only 2/14 cases of ENFL had detectable t(14;18) compared with 9/16 stage 1 nodal FL (P < 0.01). Freedom from progression and disease-specific survival was similar for the 15 cases of ENFL and 87 cases of stage 1 nodal FL. However, 13/15 patients with ENFL were disease free at the end of follow-up compared with 49/87 stage 1 nodal FL (P < 0.02).

CONCLUSIONS

The low incidence of t(14;18) and favourable outcome encountered in ENFL in this study is similar to that previously found for primary cutaneous FL. These results support the concept of a subtype of FL lacking t(14;18) involving the major breakpoint cluster region, and with a propensity to arise at extranodal sites. Despite a high relapse rate, patients with ENFL are more likely to achieve complete remission and may ultimately have a more favourable long-term prognosis than those with equivalent nodal disease.