CD5+ extranodal marginal zone B-cell (MALT) lymphoma. A low grade neoplasm with a propensity for bone marrow involvement and relapse

Leukemic-phase mucosa-associated lymphoid tissue lymphoma

A 78-year-old man presenting with leukocytosis was admitted to our hospital. The patient was asymptomatic and showed no lymphadenopathy. Peripheral blood flow cytometry revealed a leukemic-phase B-cell lymphoma with medium-to-large abnormal cells with reticulum. Positron emission tomography/computed tomography revealed abnormal uptake in the right orbit, bone marrow, and spleen. We performed immunological staining and fluorescence in situ hybridization on tissues extracted from the right orbit and bone marrow, which led to the diagnosis of mucosa-associated lymphoid tissue (MALT) lymphoma. Polymerase chain reaction analysis of immunoglobulin heavy chain rearrangements in the right orbital mass and bone marrow suggested that they were identical clones. Based on these collective findings, the diagnosis of leukemic-phase MALT lymphoma was confirmed, with sites of involvement including the bone marrow, peripheral blood, right orbit, and spleen. This is a highly rare case of leukemic MALT lymphoma.

Breast MALT Lymphoma: A Clinical, Histomorphologic, and Immunophenotypic Evaluation

Introduction. Primary breast extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is rare and understudied. Embryonically, mammary glands are developed as specialized skin appendages. It is possible that overlapping features exist between breast MALT lymphoma and primary cutaneous marginal zone lymphoma. Methods. We studied 5 primary and 6 secondary breast MALT lymphomas diagnosed in our institution during a 20-year period. Clinical and pathologic features of these lymphomas were analyzed and compared. Results. Most primary and secondary breast MALT lymphomas had similar clinical presentations as unilateral breast lesions without axillary lymphadenopathy. However, primary lymphomas tended to be diagnosed in older patients (median: 77 years old) than secondary lymphomas (median: 60 years old). Thyroid abnormality was a common finding in both primary (3/5) and secondary (5/6) lymphomas. Hashimoto's thyroiditis was diagnosed in one primary lymphoma. No distinct histopathologic findings were found in primary lymphomas. Features for primary cutaneous marginal zone lymphoma, including overexpression of IgG and IgG4 and high IgG4/IgG ratio, were absent in all primary but present in one secondary lymphoma with cutaneous origin. This secondary lymphoma also had expansion of CD30-positive cells. Conclusion. Primary breast MALT lymphoma does not share the distinctive features of primary cutaneous marginal zone lymphoma that set it apart from other extranodal marginal zone lymphomas. Having increased IgG- and IgG4-positive cells with a high IgG/IgG4 ratio in breast MALT lymphoma may indicate cutaneous origin. CD30 overexpression may be a feature seen in marginal zone lymphoma of cutaneous origin, which needs further studies to prove.

Lymphoma of the Lacrimal Sac: The Massachusetts Eye and Ear Experience With a Comparison to the Previously Reported Literature

PURPOSE

To describe the frequency, clinical features, and histologic subtypes of biopsy proven lacrimal sac lymphomas, and to compare these results to the previously published literature.

METHODS

A retrospective chart review was performed at a single institution from 2004 to 2017. Pathology reports, operative notes, and patients' medical charts were reviewed.

RESULTS

Of 566 lacrimal sacs submitted for routine histopathologic evaluation, 16 cases of lymphoma were identified. All were low-grade, non-Hodgkin B-cell lymphomas, biopsied at an average age of 71 years. Thirteen patients (81.25%) had a pre-existing lymphoma diagnosis; the average interval between the diagnosis of systemic or nonocular adnexal lymphoma and lacrimal sac lymphoma was 7.9 years (range 2-26 years; median 5.5 years). Three cases of primary lacrimal sac lymphoma were identified. Histopathology showed 3 cases (18.75%) of follicular lymphoma, 3 (18.75%) of extranodal marginal zone lymphoma, and 10 (62.5%) of chronic lymphocytic leukemia/small lymphocytic lymphoma. Primary cases presented with epiphora and nasolacrimal duct obstruction, while secondary cases predominantly manifested as dacryocystitis. All lacrimal sac neoplasms were locally responsive (without local recurrence) to chemotherapy, radiation, or both.

CONCLUSIONS

Lacrimal sac lymphoma is uncommon but should be suspected among patients with known lymphoma who develop dacryocystitis. In this series, primary lacrimal sac lymphoma most often presented as a mass or nasolacrimal duct obstruction. Chronic lymphocytic leukemia/small lymphocytic lymphoma was the most commonly identified cause of secondary lacrimal sac lymphoma. Distinguishing primary from secondary lacrimal sac lymphomas is important, as the extent of disease and histopathologic subtypes differ, which may affect patient management.

Primary oral mucosa-associated lymphoid tissue (MALT) lymphoma in patient with monoclonale gammopathy: a rare case report

Background

Monoclonal gammopathy is a biological reality encountered in approximately 1% of the general population. In the absence of clinical and biological signs, it is considered of undetermined significance; however, it can be a biological signature of a monoclonal lymphocytic or plasma-cell proliferation. Their localisation to the oral mucosa remains rare and difficult to diagnose, particularly in indolent forms that escape imaging techniques.

Case presentation

Here, we report the case of a 73-year-old woman with a history of IgM kappa gammopathy followed for 13 years. The patient did not have a chronic infection or an autoimmune disease, and all the biological investigations and radiological explorations were unremarkable during this period. The discovery of a submucosal nodule in the cheek led to the diagnosis of MALT lymphoma and regression of half of the IgM kappa level after resection. The review of the literature shows the dominance of clinical signs (i.e., a mass or swelling) in the diagnosis of primary MALT lymphomas of the oral cavity after surgical resection.

Conclusions

Our case illustrates the role of examination of the oral cavity in the context of a monoclonal gammopathy. The absence of clinical and radiological evidence in favor of lymphoplasmacytic proliferation, does not exclude a primary indolent MALT lymphoma of the oral mucosa.

MALT lymphoma of the tongue: An unusual site that may present a diagnostic challenge

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a low-grade B cell lymphoma that can affect any organ, usually preceded by acquisition of MALT in response to antigenic stimulus provided by infections or autoimmune diseases. Most often, MALT lymphoma involves the stomach (about 35% of cases), followed by the ocular adnexal region, skin, lungs, and salivary glands, but virtually any extranodal site can be involved. MALT lymphomas are less common at sites of normal MALT tissue, such as Waldeyer ring and the ileocecal region of the gastrointestinal tract. Lymphomas involving the tongue are extremely rare and represent approximately 3% of all lymphomas involving the head and neck region. In this study, we discuss potentially challenging diagnostic aspects of MALT lymphoma involving the tongue and review and summarize the available literature about this topic.

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.

CD5 expression in marginal zone lymphoma predicts differential response to rituximab or bendamustine/rituximab

We examined outcomes of 244 patients with marginal zone lymphoma (MZL) diagnosed in 2010-2020, of which 25 (10%) expressed CD5. CD5 expression was present in 22% of splenic, 8% of nodal, and 5% of extranodal MZL, and showed frequent blood/bone marrow involvement, elevated lactate dehydrogenase, and TP53 deletions. CD5 expression was not associated with progression-free or overall survival, but it conferred a significantly higher risk of histologic transformation (22% versus 4% at 5 years, p = 0.002). Among patients receiving first-line rituximab monotherapy, CD5 expression was associated with lower response rate (30% versus 77%, p = 0.006), PFS (25% versus 45% at 3 years, p = 0.003) and OS (44% versus 77%, p = 0.010), whereas CD5 status did not significantly affect outcomes of patients receiving bendamustine with rituximab (P for interaction = 0.012 for progression-free survival). CD5-positive MZL may have a propensity to leukemic dissemination, histologic transformation, and may derive benefit from first-line bendamustine/rituximab rather than rituximab alone.

Primary Pleural Extranodal Marginal Zone Lymphoma Presenting as Bilateral Chylothorax

Here we describe a case of pleural extranodal marginal zone lymphoma presenting as bilateral chylothorax which has not been reported in the literature prior to this. Primary pleural lymphomas are a rare entity most commonly associated with chronic infections, autoimmune conditions or long-standing pyothorax which were not seen in this case. Chylous pleural effusions in this patient were successfully managed with chemotherapy for the underlying lymphoma.

CD5 expression correlates with inferior survival and enhances the negative effect of p53 overexpression in diffuse large B-cell lymphoma

De novo CD5-positive diffuse large B-cell lymphoma (CD5+ DLBCL) is increasingly recognized as a distinct pathologic phenomenon with a specific clinical picture. However, CD5+ DLBCL has not been studied on a large scale in China. In this study, we show that CD5+ DLBCL occurs at a low frequency (9.2%). Comparison of clinical characteristics of CD5+ vs CD5- DLBCL showed that CD5+ DLBCL was more frequently elderly (>60 years) and had B symptoms, high-performance status, stage III-IV, an IPI score >2 and bone marrow involvement. Patients with CD5+ DLBCL had tumours with a higher prevalence of BCL-2 and p53 overexpression than CD5- DLBCL. Patients with CD5+ DLBCL had inferior progression-free survival (PFS) and overall survival (OS) than did patients with CD5- DLBCL. For CD5+ DLBCL, the patients who were treated with rituximab showed significantly better PFS and OS than those treated without rituximab. However, patients treated with RCHOP showed similar PFS and OS when compared with the group treated with intensive therapy. In addition, patients with p53 and CD5 co-expression had the worst PFS and OS. In conclusion, CD5+ DLBCL was associated with unfavorable clinicopathologic variables and with inferior survival. CD5+ DLBCL has a high frequency of p53 overexpression, and CD5 augments the negative effect of p53 overexpression in DLBCL.

Clinicopathologic characteristics and outcomes of transformed diffuse large B-cell lymphoma in hepatitis C virus-infected patients

Hepatitis C virus (HCV) causes a chronic but curable infection associated with the development of marginal zone lymphoma (MZL) and diffuse large B-cell lymphoma (DLBCL). Preliminary data have shown frequent transformation of indolent lymphoma to DLBCL in HCV-infected patients. To compare their clinicopathologic characteristics and oncologic outcomes, we reviewed the medical records and pathology reports of HCV-infected and uninfected patients with DLBCL that transformed from indolent lymphoma seen at The University of Texas MD Anderson Cancer Center (June 2004 to May 2015). To identify predictors of DLBCL relapse, patients with relapse after first-line chemotherapy were compared with those without it using univariate and logistic regression analyses. Compared with the uninfected patients (n = 63), HCV-infected patients (n = 21) were younger (median age =54 years [interquartile range= 49-62 years] vs. 62 years [53-66 years]; p = 0.01) and more often had advanced DLBCL (Ann Arbor stage 3-4; 95% vs. 76%; p = 0.05). Immunophenotypically, more HCV-infected than uninfected patients had CD10-negative B cells (76% vs. 43%; p = 0.008), CD5-positive B cells (39% vs. 7%; p = 0.004) and activated B-cell phenotypes (57% vs. 31%; p = 0.07). Comparison of the patients who had relapse after first-line chemotherapy (n = 42) and those who did not (n = 40) revealed that having CD5-positive B cells was the only factor associated with DLBCL relapse in multivariate analysis (odds ratio= 10.7; p = 0.02). HCV-infected patients with transformed DLBCL have unique clinicopathologic characteristics that make their lymphoma difficult to treat, potentially leading to unfavorable outcome. The impact of HCV eradication should be explored in such patients.

A Case Presenting with Splenic Infarct Diagnosed as Primary Bone Marrow CD5 Positive DLBCL: A Clinicopathological Correlation

De novo CD5+ Diffuse large B cell lymphoma (DLBCL) is a rare and aggressive subtype of DLBCL. It is a distinct clinicopathologic entity with complex molecular profile and poor prognosis. A 59 year old female presented with pyrexia of unknown origin since 1 month. On examination, there was severe pallor, hepatosplenomegaly and no palpable lymphadenopathy. Complete blood count revealed bicytopenia with normal total leucocyte count. Liver and renal function tests were normal. Ultrasonography abdomen revealed splenic enlargement with two focal lesions attributed to either splenic abscess or infarcts. Patient was being managed as splenic infarct but continued to have bicytopenia. Further investigation showed elevated serum ferritin, triglycerides and LDH. With a clinical suspicion of infection and haemophagocytic lymphohistiocytosis bone marrow aspiration (BMA) and biopsy (BMBx) was done. BMA showed extensive haemophagocytosis and ~7.4 % large lymphoma-like cells. On this basis PET-CT was suggested which showed enlarged spleen with diffuse uptake. BMBx showed nodular and intrasinusoidal collection of abnormal lymphoid cells. On immunohistochemistry, these cells were positive for CD20, CD5, MUM1, BCL-2, BCL-6 and negative for CD3, CD10 and CD23. CD34 highlighted focal intrasinusoidal pattern. The complete clinicopathological profile suggested the diagnosis of de novo CD5+ DLBCL, with primary hepatosplenic pattern of involvement. CD5+ DLBCL presenting as splenic infarct is very rare. This case was unusual as the diagnosis of a primary aggressive lymphoma with haemophagocytosis was established in a patient who presented with fever and splenic infarct without lymphadenopathy. This indicates the importance of good morphological assessment of a bone marrow aspirate and biopsy to make a correct diagnosis.

Issues in diagnosis of small B cell lymphoid neoplasms involving the bone marrow and peripheral blood. Report on the Bone Marrow Workshop of the XVIIth meeting of the European Association for Haematopathology and the Society for Hematopathology

Small B cell lymphoid neoplasms are the most common lymphoproliferative disorders involving peripheral blood (PB) and bone marrow (BM). The Bone Marrow Workshop (BMW) organized by the European Bone Marrow Working Group (EBMWG) of the European Association for Haematopathology (EAHP) during the XVIIth EAHP Meeting in Istanbul, October 2014, was dedicated to discussion of cases illustrating how the recent advances in immunophenotyping, molecular techniques and cytogenetics provide better understanding and classification of these entities. Submitted cases were grouped into following categories: (i) cases illustrating diagnostic difficulties in chronic lymphocytic leukaemia (CLL); (ii) cases of BM manifestations of small B cell lymphoid neoplasms other than CLL; (iii) transformation of small B cell lymphoid neoplasms in the BM; and (iv) multiclonality and composite lymphomas in the BM. This report summarizes presented cases and conclusions of the BMW and provides practical recommendations for classification of the BM manifestations of small B cell lymphoid neoplasms based on the current state of knowledge.

MALT lymphoma of the base of the tongue: a rare case entity

Lymphoma is a malignant tumour arising from lymphoid tissue, with the majority of cases being in the lymph nodes, however, in 1/4th of cases, these tumours are found in extralymphoid tissue. Lymphoid tissue is also found in organs having mucosa, such as the digestive tract, salivary gland and in tracheal tissue. This collection of lymphoid tissue is known as mucosa-associated lymphoid tissue (MALT), and non-Hodgkin lymphoma involving this extralymphoidal lymph tissue is known as MALT lymphoma. It was first reported by Isaacson and Wright in 1983, however, it was not included as a working diagnosis in clinical use until it was reclassified as 'marginal zone B-cell lymphoma' in a 1994 Revised European American Lymphoma (REAL) classification. It is rarely seen in the head and neck region, and we report the sixth case of MALT lymphoma of the base of the tongue. A 61-year-old man presented with dysphagia and the feeling of a lump in his throat for 5 months.

Acute pancreatitis as the first manifestation of duodenal MALT lymphoma

BACKGROUND

Possibly any tumor that can cause mechanical obstruction of the distal bile duct can induce acute pancreatitis. However, acute pancreatitis as the first clinical manifestation of duodenal lymphoma is extremely rare.

OBJECTIVE

To report the case of a patient with acute pancreatitis as an extremely rare first manifestation of duodenal MALT lymphoma and possible association with erythema nodosum.

METHODS

Case report of a 66-year-old woman who was diagnosed with acute pancreatitis caused by infiltration with duodenal lymphoma.

RESULTS

Acute pancreatitis was confirmed by CT imaging. Detailed investigation revealed a duodenal mass causing pancreatic injury. Histological analysis established the diagnosis of MALT lymphoma. The patient's medical history also included erythema nodosum. Complete remission of the malignancy was achieved with chemotherapy.

CONCLUSION

This is the first published case report of acute pancreatitis caused by the growth of duodenal MALT lymphoma. An association with erythema nodosum is possible.

Clinicopathological Analysis of Ocular Adnexal Extranodal Marginal Zone B-Cell Lymphoma with IgG4-Positive Cells

This study aims to analyze clinical and pathological characteristics of ocular adnexal extranodal marginal zone B-cell lymphoma (EMZL) accompanying IgG4-positive cells. Fifty patients with a diagnosis of primary non-conjunctival ocular adnexal EMZL were enrolled in this study. The number of IgG4-positive cells and the ratio of IgG/IgG4 were evaluated by immunohistochemistry in the biopsy specimens. The patients were divided into two groups based on the absolute number and the ratio of IgG4-positive cells (IgG4-posivite vs IgG4-negative groups). The demographic data, clinical staging at diagnosis, histopathological characteristics, and response to initial treatment were comparatively analyzed between the 2 groups. Five (10%) of 50 patients were defined as IgG4-positive group, and all the cases showed characteristic histological features such as extensive plasma cell infiltration and dense fibrosis. Most of these patients (4 of 5 patients) had lymphoma of the lacrimal gland. The patients from the IgG4-positive group showed a lower response rate to initial treatment (87.5 vs 33%, p = 0.03) than IgG4-negative group with a median follow-up period of 38 months. A part of the ocular adnexal EMZLs were accompanied with IgG4-positive cells. Significantly, most IgG4-positive ocular adnexal EMZLs occurred in the lacrimal gland, and can be related with a more frequent treatment failure.

Lymphoplasmacytic lymphoma and marginal zone lymphoma in the bone marrow: paratrabecular involvement as an important distinguishing feature

OBJECTIVES

The differential diagnosis between bone marrow involvement by lymphoplasmacytic lymphoma (LPL) and marginal zone lymphoma (MZL) is challenging because histology and immunophenotype of both diseases overlap. We revisited the diagnostic pathology features of both diseases in the bone marrow.

METHODS

We studied a series of bone marrow trephine biopsy specimens from 59 patients with Waldenström macroglobulinemia without extramedullary involvement and bone marrow biopsy specimens from 23 patients with well-characterized MZL who also had bone marrow involvement. H&E- and immunoperoxidase-stained sections of bone marrow trephine biopsy specimens as well as flow cytometry and classic cytogenetics performed on aspirations were reviewed. The study was complemented with MYD88 L265P mutation analysis of all samples.

RESULTS

The most distinguishing features of LPL with respect to MZL were focal paratrabecular involvement (P < .001), the presence of lymphoplasmacytoid cells (P < .001) and Dutcher bodies (P < .001), increased numbers of mast cells (P < .001), and the MYD88 L265P mutation (P < .001).

CONCLUSIONS

LPL can be reliably distinguished from MZL in the bone marrow by using a combination of pathology characteristics. Our findings stress the diagnostic importance of using the combination of the following parameters for a correct LPL diagnosis: paratrabecular infiltration, the presence of lymphoplasmacytoid cells and cells with Dutcher bodies, and an increased number of mast cells in addition to the presence of MYD88 mutation.

Disseminated Gastric MALT Lymphoma with Monoclonal Gammopathy, t(11;18)(q21;q21), and Subsequent Development of T-Large Granular Lymphocytic Leukemia: A Case Report and Review of the Literature

Background. Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) is a well-characterized entity that may share clinical and morphological findings with other low-grade non-Hodgkin's lymphomas. Dissemination of MALT-type lymphoma to bone marrow and peripheral blood simultaneously with the presence of T-large granular cell leukemia (T-LGL) has rarely been reported. Case Presentation. This is the case of a 42-year-old male who presented with a gastric MALT-type lymphoma, disseminated to the bone marrow and the peripheral blood with high serum IgM levels and t(11;18)(q21;q21). The morphological, immunophenotypical and, immunohistochemical studies of the successive bone marrow and peripheral blood samples had revealed the coexistence of two distinct lymphoma cell populations: a B-cell, marginal zone type population expressing CD19, CD20, CD22, CD79b, IgM, and kappa light chain, and a T-large granular cell population, developed after treatment with rituximab expressing CD3, CD8, CD5, CD7, and CD45. Conclusion. Based on the analysis of this unusual case we performed an extensive review of the literature to elucidate the relationship between T-LGL and B-cell lymphomas and to emphasize the importance of paraprotein analysis at diagnosis of gastric MALT lymphoma.

Clinicopathologic features of CD5-positive nodal marginal zone lymphoma

OBJECTIVES

To describe the clinicopathologic findings of seven patients with CD5-positive nodal marginal zone lymphoma (NMZL).

METHODS

We searched cases of NMZL over a 10-year interval and identified seven cases of CD5-positive NMZL. The clinical, histologic, and immunophenotypic findings of this group were reviewed, and the frequency of dissemination in this group was compared with that of 66 patients with CD5-negative NMZL.

RESULTS

Other than CD5 expression, the histologic and immunophenotypic findings were typical of NMZL. Six (86%) of seven patients had lymphadenopathy above and below the diaphragm, and all six patients assessed had bone marrow involvement. In the CD5-negative group, 28 (42%) patients had lymphadenopathy above and below the diaphragm, and 36 (55%) had bone marrow involvement (P = .045 and P = .037, respectively). Six of seven patients were alive at last follow-up, with a median follow-up of 32 months (3-154 months).

CONCLUSIONS

CD5 expression in NMZL correlates with a higher frequency of dissemination, but patients have an indolent clinical course and excellent overall survival.

Blastic marginal zone lymphoma: a clinical and pathological study of 8 cases and review of the literature

INTRODUCTION

Blastic transformation (BT) of marginal zone lymphoma or mucosa-associated lymphoid tissue lymphoma has been mainly reported in the spleen and stomach. Primary cutaneous marginal zone lymphoma that undergoes BT is rare and not well documented. We describe 8 patients with blastic primary cutaneous marginal zone lymphoma and compare the clinical, pathologic, and molecular findings of these patients with 10 cases previously reported in the literature.

RESULTS

The cases of blastic marginal zone lymphoma could be categorized into cases of de novo blastic marginal zone lymphoma and large-cell transformation arising in a background of a history of biopsy proven marginal zone lymphoma. The cases of de novo blastic marginal zone lymphoma occurred in elderly patients without any medical history. In each of the cases, the lesions were radiated, not treated, or treated with complete excision without any death due to lymphoma nor was there any evidence of extracutaneous dissemination. Large-cell transformation arising in background of marginal zone lymphoma typically occurred in patients who were younger; 2 of the 4 cases were immunocompromised. The clinical course in each of the cases was aggressive with 3 of the 4 patients succumbing to disseminated disease while 1 patient developed extracutaneous nodal disease. Phenotypically, there was an expression of CD5 in a total of 3 of the 8 cases and CD23 in 3 of the 8 cases. Commonality of B-cell clones was demonstrated in 2 cases where biopsies were available of both the less aggressive appearing marginal zone lymphoma and the transformed biopsies. Cytogenetic abnormalities associated with BT included a deletion of chromosome 7q in all cases tested.

CONCLUSION

Large-cell transformation arising in a patient with a history of marginal zone lymphoma portends a worse prognosis, including death from disseminated disease, whereas a de novo presentation of blastic marginal zone lymphoma may define a clinical course similar to other forms of low-grade cutaneous B-cell lymphoma. The expression of CD5 and CD23 may define a phenotypic profile associated with BT. It is possible that marginal zone lymphomas associated with CD5 and CD23 positivity should be followed more closely and/or treated with radiation and/or complete excision.

Selective immunophenotyping for diagnosis of B-cell neoplasms: immunohistochemistry and flow cytometry strategies and results

Determining the immunophenotype of hematologic malignancies is now an indispensable part of diagnostic classification, and can help to guide therapy, or to predict clinical outcome. Diagnostic workup should be guided by morphologic findings and evaluate clinically important markers, but ideally should avoid the use of overly broad panels of immunostains that can reveal incidental findings of uncertain significance and give rise to increased costs. Here, we outline our approach to diagnosis of B-cell neoplasms, combining histologic and clinical data with tailored panels of immunophenotyping reagents, in the context of the 2008 World Health Organization classification. We present data from cases seen at our institution from 2004 through 2008 using this approach, to provide a practical reference for findings seen in daily diagnostic practice.

Extranodal and splenic small B-cell lymphoma

Although almost any non-Hodgkin lymphoma can involve the spleen or an extranodal site as part of more widely disseminated disease, there is a group of small B-cell lymphomas that specifically arise in these locations. These are important to recognise as some appear to have a behaviour and prognosis that is distinct from their nodal counterparts. In addition, there are entities that are specific to extranodal locations (such as extranodal marginal zone lymphoma) and to the red or white pulp of the spleen. In this review, the characteristics of these entities will be presented as well as clues to help distinguish lymphoma from reactive infiltrates in extranodal sites and measure to distinguish between small B-cell lymphomas encountered in the spleen and at extranodal locations.

CD5-positive mucosa-associated lymphoid tissue (MALT) lymphoma: a clinicopathologic study of 14 cases

Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a B-cell neoplasm that is typically CD5 negative. We describe the clinicopathologic, immunophenotypic, and cytogenetic features of 14 cases of CD5+ MALT lymphoma. There were 9 men and 5 women (median age, 68 years; range, 34-87 years). MALT lymphoma was initially diagnosed in salivary glands (n = 4), nasopharynx (n = 2), and 1 case each in conjunctiva, thyroid, stomach, colon, skin, lung, kidney, and retroperitoneum. Two patients had localized disease; 9 had disseminated disease with generalized lymphadenopathy (n = 8), multifocal lymphoma (n = 6), or bone marrow involvement (n = 5). No staging information was available for the remaining patients. None presented with B symptoms, splenomegaly, cytopenias, lymphocytosis, monoclonal gammopathy, or elevated serum lactate dehyrogenase. Serum β2-microglobulin was elevated in 6. Morphologically, the neoplasms had features typical of MALT lymphoma being composed of small- to medium-sized cells with round to slightly irregular nuclear contours and moderate amount of cytoplasm. Lymphoepithelial lesions were noted in 4 cases. CD5 was positive in all cases by immunohistochemistry (n = 12) and/or flow cytometry (n = 11). All cases assessed were negative for cyclin D1 (13/13) and CD10 (11/11). Conventional cytogenetics in 7 cases showed trisomy 3 in 3 and diploid in 4. With a median follow-up of 71 months (range, 2-131 months), overall survival at 5 years was 100%, although 5 patients required chemotherapy. Our results show that CD5 expression is rare in MALT lymphoma, and is often associated with nongastric disease and an increased tendency to present with disseminated disease. Overall survival is excellent with appropriate therapy.

CD5-positive marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) of the lung

CD5-positive marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) of the lung is very rare. An 82-year-old Japanese woman was found to have an abnormal lung shadow on chest X-ray photography, and was admitted to our hospital. Imaging modalities including X-ray photography, computed tomography, and magnetic resonance imaging showed a small (2 × 1 × 1 cm) opacity of the right upper lobe. Transbronchial lung biopsy was performed. It showed severe proliferation of small lymphocytes. The small lymphocytes were centrocytes-like, and minor plasma cell differentiation was recognized. Lymphoepithelial lesions were scattered. Immunohistochemically, the tumor cells were positive for CD5, CD20, CD43, CD45, CD79α, bcl-2, and κ-chain, but negative for CD2, CD3, CD10, CD21, CD23, CD35, CD45RO, CD56, IgA, IgG, IgM, IgD, λ-chain, TdT, and cyclin D1. The Ki-67 labeling was 10%. CD3-positive and CD45RO-positive inflammatory T-cells were scattered in small amount. The pathological diagnosis was CD5-positive marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) of the lung. The patient was treated with chemotherapy (CHOP: cyclophosphamide, hydroxydaunorbicin, vincristine, and predonisone), and the lung tumor disappeared. The patient is now free of the lymphoma 10 years after the first manifestation.

Immunohistochemical comparison of CD5, lambda, and kappa expression in primary and recurrent buccal mucosa-associated lymphoid tissue (MALT) lymphomas

Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of extranodal marginal zone B-cell lymphoma and is a distinct subtype of non-Hodgkin's lymphoma.

Primary MALT lymphomas can also occur in the oral cavity, although their appearance in this location is rare. The neoplastic cells of which MALT lymphomas are composed express B-cell antigens and show monotypic immunoglobulin expression with light-chain restriction.

Although neoplastic MALT lymphoma cells do not express CD5, previous studies have shown that CD5 positive MALT lymphomas are more prone to dissemination than those that do not express CD5. Moreover, there are some reports that describe kappa- and lambda- dual light chain expression in B cell malignant neoplasms.

A 66-year-old Japanese woman with swelling of the right buccal mucosa was referred to our hospital. The lesion was excised and was pathologically diagnosed as a MALT lymphoma tumor with a t(11;18)(q21;q21) chromosome translocation.

Swelling of the right buccal mucosa recurred 2 years later. The recurrent tumor was then excised and pathologically diagnosed as MALT lymphoma.

Immunohistochemical examination of CD5, lambda, and kappa expressions revealed that the primary tumor was positive for CD5, kappa, and lambda, but the recurrent tumor was weakly positive for CD5 and kappa.

With respect to lambda positivity, the recurrent tumor showed negativity.

Our study suggests that immunohistochemical expression of CD5, kappa, and lambda in oral MALT lymphoma have the risk of recurrence.

We first described the recurrence of CD5 positive MALT lymphoma in the oral cavity and compared the immunohistochemical expressions of CD5, lambda, and kappa between the primary and recurrent tumors.

Chronic Lymphocytic Leukemia, Small Lymphocytic Lymphoma, and Monoclonal B-Cell Lymphocytosis

Chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), and monoclonal B-cell lymphocytosis (MBL) are clonal proliferations of small, mature B cells. CLL and SLL are considered neoplastic, although they are indolent and many patients with these lymphomas never require treatment. Most MBL cases share immunophenotypic and genetic features with CLL and SLL but have a small burden of clonal cells. This review focuses on the pathologic features of CLL, SLL, and MBL and their differential diagnoses. Guidelines are provided to separate the entities from one another and to avoid pitfalls in distinguishing these entities from other lymphomas and from reactive lymphoid proliferations.

Primary ocular adnexal mucosa-associated lymphoid tissue lymphoma (MALT): single institution experience in a large cohort of patients

Extranodal marginal zone B-cell lymphoma is the most common orbital tumour. We conducted a retrospective analysis to examine: (i) the impact of initial presentation and staging on outcome and (ii) response to various treatment modalities and the effect of the latter on recurrence. Ninety patients with primary ocular adnexal marginal zone lymphoma (POAML) diagnosed at our institution between 1984 and 2009 were studied. POAML was associated with monoclonal gammopathy (13%) at presentation. Most POAML patients (86%) presented with Ann-Arbor stage I disease. Radiotherapy led to excellent local control, but relapses occurred in 18% of Ann-Arbor stage I patients during a median follow-up of 5 years. Local relapses, including secondary central nervous system (CNS) involvement, were observed in patients receiving radiation doses <30·6 Gy. No differences in relapse rate and survival were observed between patients who did or did not undergo staging bone marrow biopsy. Ann-Arbor stage II-IV disease and high lactate dehydrogenase levels were associated with shorter freedom from progression. In conclusion, POAML is an indolent lymphoma with continuous risk for relapse. Radiation doses of at least 30·6 Gy should be given in Ann-Arbor stage I disease, since lower doses may be more frequently associated with relapses, including CNS relapses.

Ocular adnexal lymphomas: a review

Ocular adnexal lymphomas comprise 1% to 2% of all non-Hodgkin lymphomas and about 8% of extranodal lymphomas. They are a heterogeneous group of malignancies, the majority of which are primary extranodal lymphoma with most (up to 80%) of the marginal zone of mucosa associated lymphoid tissue type (MALT lymphoma). This review will encompass the incidence, histology, immunophenotyping, recent advances in molecular and cytogenetics, clinical features including outcome, and prognostic factors. The association with Chlamydia psittaci and the very recently recognized occurrence in the context of IgG4-related sclerosing disease will be discussed. Finally, traditional (surgery, radiotherapy, chemotherapy) and newer forms of therapy (immunotherapy and radioimmunotherapy) will be reviewed.

CD5 expression identifies a subset of splenic marginal zone lymphomas with higher lymphocytosis: a clinico-pathological, cytogenetic and molecular study of 24 cases

BACKGROUND

Classically, splenic marginal zone B-cell lymphoma is characterized by the absence of CD5 expression. Cases of apparent splenic marginal zone B-cell lymphoma showing CD5 expression, as diagnosed by blood studies, have been described; however, in the absence of histological evidence, the correct diagnosis of these cases is controversial because of possible confusion with other CD5-positive small B-cell neoplasms.

DESIGN AND METHODS

We report a series of 24 CD5-positive, t(11;14)-negative cases of splenic marginal zone B-cell lymphoma diagnosed by flow cytometry studies of blood and histologically proven on spleen sections. Clinical data as well as morphological, immunological, cytogenetic and molecular characteristics were assessed to evaluate the similarities and differences of these cases with those of classical CD5-negative splenic marginal zone B-cell lymphoma.

RESULTS

The CD5 expression detected in blood by flow cytometry was confirmed in most cases by immunohistochemistry on spleen sections. In general, cases of CD5-positive and CD5-negative splenic marginal zone B-cell lymphoma did not appear different and, in particular, they showed similar karyotypic changes such as 7q deletion, trisomy 3, trisomy 18 and biased IGHV usage (i.e. VH1-2). The main differences were a higher lymphocyte count at diagnosis (8.15x10(9)/L versus 3.90x10(9)/L; P=0.005) and more frequent diffuse bone marrow infiltration (34% versus 8%; P=0.03) in the CD5-positive group. A tendency to a more mutated IGHV status in the CD5 positive cases was observed (80% versus 54.5%; (P=0.11). No significant differences in outcome were found in relation to CD5 expression.

CONCLUSIONS

This study confirms the existence of cases of CD5-positive splenic marginal zone B-cell lymphoma and shows that these cases are closely related to classical splenic marginal zone lymphoma. Whether or not CD5-positive splenic marginal zone B-cell lymphoma constitutes a true subset obviously requires the study of more cases.

Diffuse blastoid B-cell lymphoma: a histologically aggressive variant of t(14;18)-negative follicular lymphoma

Among the diffuse lymphomas of B-cell origin, we have encountered one variant displaying blastoid features that morphologically mimic lymphoblastic lymphoma, the blastoid variant of mantle cell lymphoma, and the so-called blastoid transformation of follicular lymphoma. To better characterize this entity, we studied eight cases morphologically, immunohistochemically, and by fluorescence in situ hybridization (FISH) for cytogenetic abnormalities commonly associated with follicular lymphoma and B-cell lymphomas exhibiting high-grade histological features. All eight cases were presented as de novo neoplasms, and displayed an entirely diffuse (five cases) or only minimal follicular (three cases) growth pattern. The neoplastic lymphoid cells were of medium size with round nuclei, fine chromatin, inconspicuous nucleoli, and high mitotic rate; they expressed CD10, BCL6, and BCL2-a phenotype consistent with follicle center cell origin. A proportion of cases expressed MUM1. Their lack of TdT and CYCLIN D1 distinguished them from lymphoblastic lymphoma and the blastoid mantle cell lymphoma, respectively. The neoplastic lymphoid cells consistently expressed CD43 (seven of eight cases) and occasionally other T-cell-associated antigens, including CD5, CD7, CD8, and CD57. Although all cases overexpressed BCL2, t(14;18) was not detected in any of the five cases examined by FISH; instead, extra copies of chromosome 18 were found in four of five cases. Finally, other cytogenetic abnormalities, including structural abnormalities of BCL6 (allelic loss/gain, rearrangement), monosomy 7, del(13)(q14), and MYC allelic loss, were frequently detected. The combination of a B-cell CD10+ BCL6+ BCL2+ phenotype in the presence of structural abnormalities of BCL6 is consistent with a follicular center cell derivation for our cases. The lack of t(14;18) seen in our cases, although rare in most cases of follicular lymphoma, has been nevertheless reported in cases of follicular lymphoma with a predominantly diffuse growth pattern. The molecular pathogenesis, clinical manifestations, and prognostic significance of these lesions remain to be elucidated.

Secondary CD5+ diffuse large B-cell lymphoma not associated with transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma (Richter syndrome)

Few cases of secondary CD5+ diffuse large B-cell lymphoma (DLBCL) that are not Richter syndrome have been reported previously. We report 9 cases of non-Richter syndrome secondary CD5+ DLBCL. Among 529 cases of DLBCL, 38 (7.2%) were CD5+ DLBCL, including 9 of secondary CD5+ DLBCL. Five cases gained CD5 expression during the clinical course of DLBCL (group 1). Three cases showed transformation from CD5- low-grade B-cell lymphoma to CD5+ DLBCL (group 2). The remaining case showed coexistence of CD5+ DLBCL and CD5+ follicular lymphoma. The clonal relationships of CD5- and CD5+ tumors were confirmed in all 4 available cases. Cases of secondary CD5+ DLBCL that were not Richter syndrome were classifiable into 3 groups. Groups 1 and 2 showed the gain of CD5 during the clinical course or transformation of the tumors, suggesting that CD5 expression is closely associated with the progression of B-cell lymphoma.

Small B-cell neoplasms with typical mantle cell lymphoma immunophenotypes often include chronic lymphocytic leukemias

Mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) are CD5+ small B-cell neoplasms (SBCNs) with overlapping features. Flow cytometric immunophenotyping is often used to help differentiate CLL from MCL, and a characteristic CLL phenotype is considered essentially diagnostic. However, previous studies have not specifically examined how well a typical MCL immunophenotype distinguishes MCL from CLL. We identified 28 cases of SBCN with typical flow cytometry-determined MCL immunophenotypes consisting mostly of peripheral blood and bone marrow specimens. Fluorescence in situ hybridization analysis indicated that 57% (16/28) had t(11;14) translocations consistent with MCL, while 32% (9/28) lacked t(11;14) translocations but harbored other cytogenetic abnormalities commonly found in CLL. There were no significant morphologic or immunophenotypic differences between the t(11;14)-positive and t(11;14)-negative cases. Our findings suggest that many blood-based SBCNs with typical MCL immunophenotypes likely represent cases of phenotypically atypical CLL, which would have important clinical implications.

Lymphomas involving the breast: a study of 106 cases comparing localized and disseminated neoplasms

Lymphomas involving the breast account for approximately 2% of extranodal and <1% of all non-Hodgkin lymphomas. Our aim in this study was to classify breast lymphomas using the World Health Organization classification and then compare this classification with clinical, histologic, and radiologic findings as well as survival. The study group included 106 patients with breast lymphoma (105 women and 1 man). The neoplasms were divided into 2 groups based on extent of disease at initial diagnosis: localized disease (n=50) and disseminated disease (n=56). The follow-up period ranged from 4 to 252 months (median, 49 mo). Almost all (97%) patients presented with a palpable breast mass or masses. In the localized group, diffuse large B-cell lymphoma (DLBCL) was most frequent (n=32, 64%). In the disseminated group, follicular lymphoma was most frequent and exclusive to this group (P=0.0004). Mucosa-associated lymphoid tissue lymphomas occurred in both groups without a significant difference in frequency. A variety of other types of B-cell and T-cell non-Hodgkin lymphomas and classical Hodgkin lymphoma involved the breast at much lower frequency; most of these neoplasms involved the breast as part of disseminated disease. The clinical presentation correlated with radiologic findings: localized lymphomas presented as solitary masses, whereas disseminated lymphomas commonly presented as multifocal masses. There was a significant difference in the disease-free survival between patients with localized and disseminated DLBCL (P=0.003). In the disseminated group, patients with DLBCL had a worse disease-free survival compared with patients with mucosa-associated lymphoid tissue lymphoma or follicular lymphoma (P=0.01).

Systemic CD5+ MALT lymphoma: presentation with Waldenstrom syndrome

We report a case of extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) in a 75-year-old woman with a neuropathy related to high levels of serum immunoglobulin M and a history of rheumatoid arthritis and polymyositis. The patient developed a mass in the right submandibular salivary gland, and this mass demonstrated histopathologic features that are typical of MALT lymphoma, including infiltrates of small monocytoid B cells in the epithelium (forming "lymphoepithelial lesions"), a reactive background of florid germinal center hyperplasia, and follicular colonization by the monocytoid B cells. Many plasma cells in the background expressed cytoplasmic immunoglobulin M lambda, matching the serum spike. Flow cytometric analysis confirmed the presence of clonal mature B cells; however, unlike most MALT lymphomas, these cells coexpressed dim CD5. Clinical staging revealed evidence of systemic distribution with documented disease involving the bone marrow, the lung, and a paratracheal lymph node. Analysis of this unusual systemic MALT lymphoma, and a comparison with similar examples from the literature, illuminates relationships among MALT lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, and Waldenstrom macroglobulinemia.

Primary cutaneous CD5+ marginal zone B-cell lymphoma resembling the plasma cell variant of Castleman's disease. Case report

Marginal zone B-cell lymphoma (MZBL) is occasionally associated with prominent plasma cell differentiation. However, MZBL rarely exhibits histological features that resemble plasmacytoma arising from a localized plasma cell variant of Castleman's disease (PCCD). We here report a histologically similar case that was associated with primary cutaneous tumor. The patient was a 57-year-old woman with a 5-year history of cutaneous nodules. Histologically, a prominent proliferation of plasma cells occupied the interfollicular area of the central portion of the cutaneous tumor, whereas various numbers of CD5+ centrocyte-like (CCL) cells, which were arranged in a marginal zone distribution pattern, occupied the peripheral region of the tumor. The majority of the lymphoid follicles had atrophic or regressive germinal centers resembling hyaline-vascular Castleman's disease. CCL cells were observed to have colonized a few of the lymphoid follicles. Immunohistochemistry revealed that these cells had a monotypic intracytoplasmic kappa chain. Without treatment, the patient was quiescent, but 2 years later, there was a transformation to the large cell type. These observations suggest that MZBL needs to be distinguished from PCCD, and that untreated cutaneous MZBL may undergo a high-grade blastic transformation similar to other indolent lymphoproliferative disorders.

Application of Immunohistochemistry in the Diagnosis of Non-Hodgkin and Hodgkin Lymphoma

Context.—Beginning with the immunologic classifications of Lukes and Collins and Kiel and culminating in the Revised European-American Lymphoma and World Health Organization classifications, the diagnosis of lymphoid tumors relies heavily on the determination of cell lineage, maturation, and function, based on antigen expression in addition to morphology and clinical features. Technologic advances in immunology, antibody production, genetic analysis, cloning, and the identification of new genes and proteins by microarray and proteomics have provided pathologists with many antibodies to use in routine diagnosis.

Objective.—To provide guidance to the practicing pathologist in the appropriate selection of an antibody panel for the diagnosis of lymphoma based on morphology and relevant clinical data and to avoid pitfalls in the interpretation of immunohistochemical data. Attention is given to some of the newer antibodies, particularly against transcription factors, that are diagnostically and prognostically useful.

Data Sources.—The information presented in this article is based on review of the literature using the OVID database (Ovid MEDLINE 1950 to present with daily update) and 20 years of experience in diagnostic hematopathology.

Conclusions.—Immunophenotyping is required for the diagnosis and classification of lymphoid malignancies. Many paraffin-reactive antibodies are available to the pathologist but most are not specific. To avoid diagnostic pitfalls, interpretation of marker studies must be based on a panel and knowledge of a particular antigen's expression in normal, reactive, and neoplastic conditions.

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue arising in the extracranial head and neck region: a high rate of dissemination and disease recurrence

Nongastrointestinal mucosa-associated lymphoid tissue (MALT) lymphoma, although generally indolent in nature, has variable and heterogeneous clinical course and biologic behavior. We have evaluated the clinical features and follow-up of patients with MALT lymphomas involving the head and neck in our institution. Forty-four new patients with MALT lymphomas arising in ocular adnexa (24 patients, group A) and other head and neck sites (20 patients, group B) of the salivary gland (13), thyroid gland (3) and other regions (4) were retrospectively analyzed. At initial diagnosis, 21 patients had solitary lesions (16/24 in the group A vs. 5/20 in the group B, P=.008); 23 had disseminated disease at multiple sites (11 patients) and/or lymph node involvement (15 patients: 3/24 in the group A vs. 12/20 in the group B, P=.025). Treatment consisted of local therapy, consisting of surgical resection and/or radiotherapy, in 34 patients and systemic chemotherapy with/without local therapy in 10 patients. Eight patients experienced tumor recurrence: four patients died of disease, two were alive with disease, and two were disease-free at last follow-up. With a mean follow-up of 46 months, the 5-year overall survival and relapse-free rates were 83% and 74%, respectively, which did not differ between the two groups (P>.5). Patients with MALT lymphomas of the head and neck are at relatively high risk for multifocal or lymph node involvement. Recurrence at prolonged times after therapy indicates the need for close long-term monitoring, and for prospective trials to prevent recurrence.

Flow cytometric immunophenotyping for hematologic neoplasms

Flow cytometric immunophenotyping remains an indispensable tool for the diagnosis, classification, staging, and monitoring of hematologic neoplasms. The last 10 years have seen advances in flow cytometry instrumentation and availability of an expanded range of antibodies and fluorochromes that have improved our ability to identify different normal cell populations and recognize phenotypic aberrancies, even when present in a small proportion of the cells analyzed. Phenotypically abnormal populations have been documented in many hematologic neoplasms, including lymphoma, chronic lymphoid leukemias, plasma cell neoplasms, acute leukemia, paroxysmal nocturnal hemoglobinuria, mast cell disease, myelodysplastic syndromes, and myeloproliferative disorders. The past decade has also seen refinement of the criteria used to identify distinct disease entities with widespread adoption of the 2001 World Health Organization (WHO) classification. This classification endorses a multiparametric approach to diagnosis and outlines the morphologic, immunophenotypic, and genotypic features characteristic of each disease entity. When should flow cytometric immunophenotyping be applied? The recent Bethesda International Consensus Conference on flow cytometric immunophenotypic analysis of hematolymphoid neoplasms made recommendations on the medical indications for flow cytometric testing. This review discusses how flow cytometric testing is currently applied in these clinical situations and how the information obtained can be used to direct other testing.

The critical role of histology in an era of genomics and proteomics: a commentary and reflection

The role of histologic examination in lymphoma diagnosis has been called into question by proponents of new technologies, such as genomics and proteomics. We review the history and salient features of morphologic evaluation in lymphoid diseases, and discuss the general and specific limitations of mature ancillary techniques, such as immunohistochemistry, flow cytometry, and molecular studies. We then speculate on the future relationship between morphology and the new genomic and proteomic technologies as they become integrated into clinical practice.