Rituximab monotherapy as a first-line treatment for pulmonary mucosa-associated lymphoid tissue lymphoma

A Rare Case of Primary Pulmonary Diffuse Large B-Cell Lymphoma Transformed from Marginal Zone Mucosa-Associated Lymphoid Tissue Lymphoma

Primary pulmonary lymphoma is a rare neoplasm characterized by the proliferation of lymphoid tissue affecting the lungs. The most common subtype is marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT). Rarely, a MALT lymphoma transforms into a diffuse large B-cell lymphoma (DLBCL). Treatment options include chemotherapy, radiotherapy, immunotherapy, and surgery. Here, we describe a patient with a primary pulmonary MALT lymphoma transforming into DLBCL. The purpose of this case report is to raise awareness of the relevant clinical and imaging features and to emphasize the need for a multidisciplinary approach to optimal management. In addition, we screened the PubMed and Embase databases for similar reports with a confirmed presence of transforming lymphoma within the lungs.

A Case of Persistent Lung Masses After Treatment of Hodgkin Lymphoma

CASE PRESENTATION

The patient is a 49-year-old woman who had never used tobacco with a history of relapsing polychondritis and episcleritis. She sought treatment at our clinic for evaluation of multiple lung masses. She originally received a diagnosis by chest radiography performed to rule out sarcoidosis as the cause of episcleritis showing an abnormal findings. She had no contributory surgical, family, or social history. The autoimmune markers were notable for positive rheumatoid factor (153 IU/mL) and elevated erythrocyte sedimentation rate (97 mm/h) and C-reactive protein (65.5 mg/L). Pertinent studies with negative results included antineutrophilic cytoplasmic antibody, antinuclear antibody, cyclic citrullinated peptide antibody, Sjogren syndrome-related antigen A, and Sjogren syndrome-related antigen B tests.

Primary pulmonary mucosa-associated lymphoid tissue lymphoma: A case report

Primary pulmonary lymphoma (PPL) is a rare entity with the most common presentation as mediastinal lymphadenopathy. The most common form of PPL is Mucosa-Associated Lymphoid Tissue Lymphoma (MALToma) which is an extranodal B-cell lymphoma originating from the mucosal layers involving different organs such as the gastrointestinal tract as well as the lung. Herein, we present a case of a 51-year-old woman with progressive dyspnea for 6 months and no prior medical history. The computed tomography (CT scan) revealed bilateral multifocal consolidation and ground-glass opacities as well as interlobular septal thickening. Bronchoscopy was normal and CT-guided biopsy of lung consolidations was conclusive of MALToma. Complete extrapulmonary evaluations inducing bone marrow aspiration were unremarkable. The primary pulmonary MALToma is an extremely rare entity that presents with non-specific symptoms and a wide variety of CT findings such as mediastinal, hilar lymphadenopathy, and single or multiple lung nodules ranging from 2 to 8 cm. the disease has a favorable prognosis, so prompt diagnosis is essential.

Extranodal localization of non-Hodgkin's lymphoma in systemic sclerosis: A diagnostic challenge and review of the literature

Background

Systemic sclerosis is associated with an increased incidence of malignancies, in particular solid neoplasms. Hematological cancers have been also observed in autoimmune diseases, though rarely present with lung involvement. The latter may be misdiagnosed in systemic sclerosis patients, due to the frequent concomitant interstitial lung disease.

Case description

Here, we present the case of a 63-year-old man affected by systemic sclerosis presenting with an atypical lung imaging and splenomegaly, who was diagnosed with splenic marginal zone lymphoma, thus raising the suspicion of lung secondarism. We discuss the diagnostic challenge of differential diagnosis in interstitial lung presentation and briefly review the available literature on this topic.

Conclusion

Several reports have demonstrated an increased risk of malignancy in patients with systemic sclerosis. Still, the lack of concretely defined guidelines for systemic sclerosis, along with systemic sclerosis multifaceted organ involvement at presentation, may challenge diagnosis and management. Here, we remark the importance of clinical work-up and a multidisciplinary approach in systemic sclerosis, to early detect and treat concomitant hematological malignancies, especially during the first years of the disease.

Surgery and chemotherapy cannot improve the survival of patients with early-stage mucosa-associated lymphoid tissue derived primary pulmonary lymphoma

Background

To date, there is no treatment consensus on mucosa-associated lymphoid tissue (MALT) derived primary pulmonary lymphoma (PPL).

Methods

We identified patients with early-stage MALT-type PPL from the National Cancer Institute’s Surveillance, Epidemiology, and End Results program database. The patients were divided into four groups according to treatment modalities: None of surgery or chemotherapy (None) group, Surgery alone group, Chemotherapy alone (Chemo alone) group, and Surgery plus chemotherapy (Surgery + chemo) group. Overall survival (OS) and cancer-specific survival (CSS) were study endpoints. We performed Cox regression analyses, propensity score-matched analyses (PSM) and Kaplan-Meier (KM) survival curves to compare the survival among different groups.

Results

A total of 953 patients were included in our analysis with 302, 403, 175, and 73 cases in the None, Surgery alone, Chemo alone, and Surgery + chemo groups, respectively. In this cohort, the estimated 3-year, 5-year and 10-year OS rates were 86.95%, 78.91%, and 55.89%, respectively. Meanwhile, the estimated 3-year, 5-year and 10-year CSS rates were 96.71%, 93.73%, and 86.84%, respectively. Multivariate Cox regression analyses demonstrated that increasing age, tumors located in the lower lobe, and stage II were significant predictors of poorer OS while increasing age and tumors located in the bilateral lungs were associated with lower CSS. After PSM analyses, the KM survival curves showed no significant differences in OS or CSS among the four groups.

Conclusion

Early-stage MALT-type PPL is indolent in nature. Neither surgery, chemotherapy nor a combination of surgery and chemotherapy can improve OS and CSS, suggesting that “watch and wait” may be a reasonable alternative.

Extranodal Marginal Zone Lymphoma: Pathogenesis, Diagnosis and Treatment

Simple Summary

Extranodal marginal zone lymphoma (EMZL) is an indolent lymphoproliferative disease morphologically composed of small heterogeneous B lymphocytes. It generally occurs with a localized stage and can arise in various organs, the most frequent being the stomach, lung, and ocular adnexa. Depending on the presentation and the possible association with infectious agents, different therapeutic approaches are to be undertaken. The purpose of this review is to describe the biology underlying this pathology, the diagnostic, and therapeutic approach.

Abstract

Extranodal Marginal Zone Lymphoma (EMZL lymphoma) is an indolent B-cell lymphoma with a median age at diagnosis of about 60 years. It accounts for 7–8% of all B-cell lymphomas. It can occur in various extranodal sites, including stomach, lung, ocular adnexa, and skin; furthermore, the disseminated disease can be found in 25–50% of cases. Several infectious agents, such as Helicobacter pylori (H. Pylori) in the case of gastric Mucosa Associated Lymphoid Tissue (MALT) Lymphoma, can drive the pathogenesis of this cancer, through the autoantigenic stimulation of T cells, but there may also be other factors participating such autoimmune diseases. Initial staging should include total body computed tomography, bone marrow aspirate, and endoscopic investigation if indicated. Fluorescence in situ hybridization (FISH), should be performed to detect the presence of specific chromosomal translocations involving the MALT1 and BCL10 genes, which leads to the activation of the NF-κB signaling pathway. Depending on the location and dissemination of the disease, different therapeutic choices may include targeted therapy against the etiopathogenetic agent, radiotherapy, immunochemotherapy, and biological drugs. The purpose of this review is to illustrate the complex biology and the diagnosis of this disease and to better define new treatment strategies.

Watch-and-wait or immediate immunotherapy/immunochemotherapy in patients with phase IE primary pulmonary MALT lymphoma? A multicenter retrospective study

Primary pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma is rare, and the optimal frontline treatment has not taken shape so far. It is still debatable whether the watch-and-wait (W&W) policy is beneficial to patients, especially in the early stage. This study was to compare the efficacy of W&W with rituximab single agent or combined chemotherapy (R/R-Chemo) on primary pulmonary MALT patients with localized disease. Clinical characters and effect on 28 patients with primary pulmonary MALT (IE phase) were analyzed. Among the 28 patients, 14 were grouped into W&W cohort, and 14 were immediately treated with R/R-Chemo. The median follow-up duration was 62 months. The estimated median time to treatment failure (TTF) in the W&W cohort and immediate R/R-Chemo cohort was 29 months and 59 months, which were not significantly different (P = 0.667). The estimated median time of overall survival (OS) in the W&W cohort and immediate R/R-Chemo cohort was 78 months and 76 months, which were also not statistically significant (P = 0.696). Concerning prognosis, there is no difference between patients with primary pulmonary MALT (IE phase) treated with W&W and with timely R/R-Chemo.

Primary Pulmonary B-Cell Lymphoma: A Review and Update

Simple Summary

The group of B-cell lymphomas primarily involving the lung encompasses different histological entities with distinct biological aspects, while sharing some clinical and radiological features related to their common anatomic site of occurrence. Recent molecular advances in the molecular genetics of these lesions have substantially improved of our understanding of the mechanisms of lymphomagenesis, adding novel information to histology in order to better characterize and manage these diseases. This review summarizes the available clinical, radiological, pathological, and molecular data on primary pulmonary B-cell lymphomas, discusses the mechanisms of lymphomagenesis, and highlights the role of a multi-disciplinary management in overcoming the diagnostic and therapeutic challenges in this setting.

Abstract

Primary pulmonary B-cell lymphomas (PP-BCLs) comprise a group of extranodal non-Hodgkin lymphomas of B-cell origin, which primarily affect the lung without evidence of extrapulmonary disease at the time of diagnosis and up to 3 months afterwards. Primary lymphoid proliferations of the lung are most often of B-cell lineage, and include three major entities with different clinical, morphological, and molecular features: primary pulmonary marginal zone lymphoma of mucosa-associated lymphoid tissue (PP-MZL, or MALT lymphoma), primary pulmonary diffuse large B cell lymphoma (PP-DLBCL), and lymphomatoid granulomatosis (LYG). Less common entities include primary effusion B-cell lymphoma (PEL) and intravascular large B cell lymphoma (IVLBCL). A proper workup requires a multidisciplinary approach, including radiologists, pneumologists, thoracic surgeons, pathologists, hemato-oncologists, and radiation oncologists, in order to achieve a correct diagnosis and risk assessment. Aim of this review is to analyze and outline the clinical and pathological features of the most frequent PP-BCLs, and to critically analyze the major issues in their diagnosis and management.

Treatment and prognosis of primary pulmonary lymphoma: A long-term follow-up study

Primary pulmonary lymphoma (PPL) is a rare disease with not well-defined optimal treatment. Outcomes and follow-up are variable in published data.

OBJECTIVES

To define the outcome and optimal treatment strategies in PPL.

METHODS

We reviewed the medical records of 49 patients with PPL treated in three Italian Hematological Institutions between 2002 and 2018.

RESULTS

Thirty-eight (77.5%) cases were indolent PPL, and 11 (22.5%) cases were aggressive PPL. The majority of patients were asymptomatic at diagnosis, early stages (stages IE-IIE), normal serum LDH, no bone marrow involvement, and low or low-intermediate risks of IPI. Local therapy ± immunotherapy or immuno-chemotherapy was possible in 18/49 (37%) patients. Twenty-eight (57%) patients were treated with immuno-chemotherapy after biopsy. Waiting and watching were reported in 3 (6%) patients. Overall, the CR and ORR were 83.7% and 95.9%. With a median follow-up of 62.5 months (range 0.8-199 months), the estimated 5- and 10-year OS rates were 85% and 72.3% for all patients, 89.2% and 80.3% for indolent PPL, and 70.7% and 47.1% for aggressive PPL. Aggressive PPL tended to have a high risk of progression in the first months (P = .056). No advantages were found for indolent PPL who received immuno-chemotherapy or more conservative approaches.

CONCLUSION

Our studies confirm the epidemiological and favorable survival of patients with PPL, suggesting a very conservative approach, particularly in indolent subtypes.

Clinical and radiological characteristics of patients with pulmonary marginal zone lymphoma: A single center analysis

Pulmonary marginal zone lymphoma (PMZL) is the most common non‐Hodgkin lymphoma affecting the lung. PMZL is usually an indolent disease. Clinical and radiological variables associated with shorter survival are largely unknown and no consensus exists on preferred treatment strategy in PMZL. Herein we aimed to identify clinical and radiological features associated with shorter survival and inferior treatment outcomes. Forty patients with PMZL were analyzed. FDG‐avid disease was evident in most patients (93%) with staging PET/CT (n = 15). With a median follow‐up in treated patients (n = 38) of 8.4 years (range 0.07‐18.44), the median progression‐free survival (PFS) and overall survival (OS) were 7.5 years (95% CI 1.8‐9.5) and 15.7 years (95% CI 9.3‐NE) respectively. Shorter PFS was observed in patients who presented at diagnosis with elevated LDH, B symptoms, advanced stage and failed to achieve complete response (CR) after initial treatment. Patients with multifocal lung disease, extrapulmonary MZL and cavitary lesions on CT scans exhibited shorter PFS. Nevertheless, no clinical or radiologic findings were associated with shorter OS. All patients treated with surgery (n = 4) and radiation therapy (n = 3) achieved and remained in CR. No higher grade transformations occurred during the follow‐up period. PMZL exhibited excellent outcomes with a 15‐year PMZL‐related OS of 94.9% (95% CI: 81.25%‐98.7%). Radiation therapy and surgery are potentially curative strategies in localized PMZL.

Clinical characteristics, diagnosis, treatment, and prognostic factors of pulmonary mucosa-associated lymphoid tissue-derived lymphoma

Primary pulmonary mucosa‐associated lymphoid tissue‐derived (MALT) lymphoma is a rare disease with a favorable prognosis. However, its clinical characteristics, diagnosis, treatment, and prognoses remain unclear. We retrospectively analyzed 80 patients with pathologically confirmed MALT lymphoma from 2006 to 2018. The clinical characteristics, diagnosis, treatments, and prognoses of all the 80 patients were recorded. Patients were stratified into surgery and biopsy groups, respectively, to evaluate the role of surgery in the diagnosis and treatment of MALT lymphoma. The prognoses were compared between different clinical characteristics and treatments. Pathological diagnoses were confirmed by surgery, bronchoscopy, and percutaneous biopsy. Thirty patients were treated by surgery. While MALT lymphoma was only diagnosed by bronchofiberoscopy or bercutaneous biopsy in four of 18 patients in the surgery group who underwent the procedure. Six patients received adjuvant chemotherapy and one patient received involved‐field radiotherapy in surgery group. Thirty‐one patients were treated with chemotherapy alone, one patient was treated with radiotherapy, one patient received only symptomatic and supportive treatment, and waiting and watching without treatment were recommended in 17 patients in biopsy group. Eight patients died during follow‐up and the 5‐year survival rate was 87.1%. Tumor number, treatment, and age were prognostic factors for overall survival (OS), but age was the only independent prognostic factor according to multivariate analysis. While, tumor number was the only prognostic factor in the analysis about progression‐free survival (PFS). No significant difference was found in OS or PFS between patients treated with and without surgical resection. MALT lymphoma is an indolent disease with favorable treatment outcome. Tumor number is associated with PFS and age is the only significant prognostic factor for pulmonary MALT lymphoma patients because of its indolent nature, but surgery still plays an important role in the diagnosis and treatment of MALT lymphoma.

Rare Primary Pulmonary Marginal Zone Lymphoma Presenting with Incidental Pulmonary Nodules

Pulmonary malignancies carry a significant morbidity and mortality and are one of the leading causes of cancer-related deaths worldwide. Primary pulmonary lymphoma is a rare malignancy which should be considered in the differential of solitary pulmonary nodule or lung mass especially in a low-risk patient presenting with constitutional symptoms. Here, we describe a case of an elderly male who presented to our clinic with incidental pulmonary nodules and subsequent workup revealed low grade B cell non-Hodgkin's lymphoma consistent with diagnosis of primary pulmonary marginal zone lymphoma.

Primary mucosa-associated lymphoid tissue (MALT) lymphoma of the lacrimal drainage system in two pediatric patients

Primary non-Hodgkin lymphoma (NHL) of lacrimal drainage system (LDS) is quite rare in children, but it is important to expedite early diagnosis in an effort to alter possible life-threatening disease since they are usually misdiagnosed as chronic dacryocystitis. In the literature, there are few examples of tumors of LDS in children. The authors herein report two pediatric cases of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) originating from lacrimal sac in an attempt to increase the knowledge about the clinical course of NHL of LDS. Considerable care must be taken since tumors of lacrimal drainage can mimic dacryocystitis clinically and macroscopically. Two patients both attended with painless swelling in the left lacrimal sac region and epiphora of the left eye. Orbital magnetic resonance imaging showed a tumoral lesion in the left lacrimal sac region and histopathological examination of excisional biopsy specimen demonstrated MALT lymphoma in both patients. The treatment regimen comprises lacrimal sac excision within the tumor, canalicular dacryocystorhinostomy (DCR) with bicanalicular silicone intubation (BSI) combined with chemotherapy and regional radiotherapy in one case, whereas the second case received only radiotherapy after canalicular DCR with BSI. Both of them maintained clinical remission along follow-up.

Retrospective Analysis of 9 Cases of Primary Pulmonary Mucosa-Associated Lymphoid Tissue Lymphoma and Literature Review

Background

Primary pulmonary mucosa-associated lymphoma tissue lymphoma is rare and is often misdiagnosed because of its diverse and nonspecific clinical features. The aim of this study was to raise awareness among clinicians and to share our experience of treating and managing such patients.

Material/Methods

This retrospective study was conducted between 1 January 2009 and 31 October 2017 at the First Affiliated Hospital of Guangxi Medical University. All cases were confirmed via pathology and immunohistochemistry. In addition, we reviewed all relevant literature.

Results

Altogether, 21 patients (7 female, 14 male) with a median age of 54 (range, 19–84) years were diagnosed with primary pulmonary mucosa-associated lymphoma. Expiratory dyspnea, repeated cough and expectoration, and weight loss were the most common symptoms. Pulmonary lesions were found via physical examination in 10 patients who had no obvious symptoms. Chest computed tomography showed nodules, pulmonary consolidation, bronchial bronchogram, ground-glass opacity, and mediastinal lymph node enlargement. Some patients were misdiagnosed with tuberculosis and pneumonia, while others were initially diagnosed with cancer. Tumor pathology and immunocytochemistry indicated primary pulmonary mucosa-associated lymphoma tissue lymphoma. Six patients underwent chemotherapy, 5 underwent surgery, 4 underwent surgery and chemotherapy, 3 were only observed, and 3 refused treatment.

Conclusions

The development of primary pulmonary mucosa-associated lymphoid tissue lymphoma is slow and insidious. Having no specific clinical symptoms and imaging findings, it is easily misdiagnosed. Final diagnosis is made via pathologic evaluation and immunohistochemistry. Surgery and chemotherapy are the primary treatment modalities and yield a good prognosis.

Pulmonary extranodal marginal zone lymphoma that presented with macroglobulinemia and marked plasmacytic cell proliferation carrying the t(14;18)(q32;q21)/MALT1-immunoglobulin heavy-chain fusion gene in pleural fluid

An 80-year-old man presented with the accumulation of pleural fluid in the right thoracic cavity. Serum electrophoresis revealed an M-component and immunofixation confirmed IgM/λ. The level of IgM was 1,526 mg/dL. Imaging studies showed an infiltrative condition of the ipsilateral lung parenchyma. The fluid contained abundant neoplastic cells with the morphological and immunophenotypic features of plasma cells, which expressed IgM/λ monoclonal immunoglobulins on the cell surface and in the cytoplasm. The karyotype was 48,XY,+3,add(9)(p13),+12,add(14)(q32),del(16)(q22),−18,+mar, and a series of fluorescence in situ hybridization studies demonstrated that the add(14) chromosome represented der(14)t(14;18)(q32;q21), at which the MALT1-immunoglobulin heavy-chain (IGH) fusion gene was localized. A long-distance polymerase chain reaction amplified the fragment encompassing the two genes, showing that the junction occurred at the J6 segment of IGH and 3.7-kb upstream of the MALT1 breakpoint cluster. We propose that this case represents an extreme form of the plasmacytic differentiation of extranodal marginal zone lymphoma that developed in the lung.

A single center experience: rituximab plus cladribine is an effective and safe first-line therapy for unresectable bronchial-associated lymphoid tissue lymphoma

BACKGROUND

Bronchial-associated lymphoid tissue (BALT) lymphoma is a relatively rare form of B-cell non-Hodgkin lymphoma (B-NHL). To date, the standard systemic treatment for this disease is still under debate, and few data are accessible for newly diagnosed unresectable BALT lymphoma presented with advanced disease. The combination of rituximab (R) and cladribine (2-CdA) has shown some activity in indolent B-NHL, but its usage has not been tested in disseminated BALT lymphoma so far.

METHODS

An observational retrospective study was performed on homogeneous data of 8 patients with biopsy-proven stage IV BALT lymphoma to assess the efficacy and the safety of R-2-CdA therapy. All but one of the patients received six courses of R-2-CdA regimen consisted of rituximab 375 mg/m² IV day 1 and cladribine 0.1 mg/kg IV days 1-4 every 21 days; one patient completed 4 cycles and received additional R maintenance.

RESULTS

A high overall response rate (ORR) was observed (100%), with 2 patients (25%) achieved a complete remission (CR), the remaining (75%) a partial response. Improvement of pulmonary function was observed in all tested patients. Grade 3 and 4 toxicities were leukocytopenia and neutropenia in 3 patients (37.5%), diarrhea in one (12.5%). Estimated two-year progression-free survival (PFS) and 2-yr overall survival (OS) were 80.0% (95% CI, 20.3-96.7%) and 100%, respectively.

CONCLUSIONS

R-2-CdA therapy demonstrated high activity and tolerable toxicity in chemotherapy-naïve patients with unresectable BALT lymphoma of advanced stage. Although further large-scale study is needed for consolidation, R-2-CdA regimen could be a good first-line therapy option for patients with unresectable BALT lymphoma.

Primary rectal mucosa-associated lymphoid tissue lymphoma in a patient with previously identified primary biliary cirrhosis and secondary Sjögren's syndrome

An 83-year-old female began treatment with prednisolone and ursodeoxycholic acid at 62 years of age, following a diagnosis of primary biliary cirrhosis (PBC) and secondary Sjögren’s syndrome (SjS). With persisting bloody stools, the patient underwent colonoscopy at 83 years of age. Histopathological evaluation revealed mucosa-associated lymphoid tissue (MALT) lymphoma. The elevated rectal lesion resolved with rituximab treatment. We report this case because although patients with SjS are at increased risk of malignant lymphoma, primary rectal MALT lymphoma is very uncommon in association with PBC and secondary SjS.

Update in primary pulmonary lymphomas

PURPOSE OF REVIEW

Despite the fact that primary pulmonary lymphoma (PPL) is a rare lung tumour, significant advances addressing clinical features, histological diagnosis, prognostic criteria and therapeutic management of this disease have been made within the past decade.

RECENT FINDINGS

Monoclonality and phenotyping of alveolar lymphocytes are suggestive of mucosa-associated lymphoid tissue (MALT). Detection of MALT-1 gene rearrangements in bronchoalveolar fluid cells using fluorescence in-situ hybridization techniques helps to confirm the diagnosis of MALT PPL. Fine needle aspiration-computed tomography guided biopsies as well as transbronchial/cryobiopsies provide adequate tissue material for histological evaluation. Recent publications also provide a better appreciation of newer chemotherapeutic approaches, including fludarabine and mitoxantrone with or without ritubximab for the treatment of MALT, as well as complete surgical resection if local disease is present. Prognostic factors influencing survival and optimal therapy for MALT have not been well defined, but the use of tumour microvascular density appears promising.

SUMMARY

This review outlines the implications of recent findings for clinical practice and research progress of PPL. Larger, multicentre and well designed studies are imperative to optimize the current diagnostic and therapeutic approach for this disease.

Rituximab-induced Acute Thrombocytopenia in High Tumor Burden Follicular Lymphoma

Rituximab-induced acute thrombocytopenia (RIAT), a rare complication of rituximab administration, has not yet been described in follicular lymphoma (FL). A 65-year-old man received rituximab for the treatment of high tumor burden follicular lymphoma in the leukemic phase. The next day, his platelet count abruptly dropped from 85,000 to 5,000/μL, which spontaneously recovered in a few days without specific treatment. We speculate that the occurrence of infusion-related cytokine release syndrome in rituximab-sensitive high tumor burden FL contributed to the development of RIAT. Frequent monitoring of the platelet count is advisable for select patients considered to be at a high risk for RIAT.

Primary Pulmonary Lymphomas

Primary lung lymphoma (PLL) is a rare disease that comprises <0.5% of all primary lung tumors. It is defined as lymphoma confined to the lung with or without hilar lymph node involvement at the time of diagnosis or up to 3 months thereafter. Patients with PLL may be asymptomatic or manifest nonspecific clinical symptoms, for example, cough, chest pain, and dyspnea. Some individuals may be immunosupressed or have an autoimmune disorder. Radiologically, PLL can mimic pneumonia, lung carcinoma, or metastasis, and therefore, histologic confirmation is mandatory for definitive diagnosis. Primary lung marginal zone lymphoma of mucosa-associated lymphoid tissue type comprises 70% to 80% of cases. Less common B-cell lymphomas include diffuse large B-cell lymphoma, lymphomatoid granulomatosis (LyG), plasmacytoma, and other small lymphocytic lymphomas. PLLs of T-cell origin, largely represented by anaplastic large cell lymphoma, are extremely rare. LyG is an Epstein-Barr virus (EBV)-driven B-cell lymphoid neoplastic proliferation rich in T cells that produces vasculitis. The disease may present at different stages of progression. Differential diagnosis of PLL varies according to the lymphoma subtype: pulmonary mucosa-associated lymphoid tissue lymphoma should be distinguished from reactive inflammatory conditions, whereas high-grade lymphomas may resemble poorly differentiated lung carcinoma, metastatic disease, and other lymphomas. LyG can resemble inflammatory, infectious, and other lymphoid neoplastic processes. A panel of immunohistochemical markers, flow cytometry, and molecular methods are necessary to confirm the diagnosis in the majority of cases. In this article we review the clinical, radiologic, pathologic, and molecular characteristics of several B-cell and T-cell PLLs with exception of Hodgkin lymphoma and posttransplant lymphoproliferative disorder.