Pyothorax-associated lymphoma (PAL): a western case with marked angiocentricity and review of the literature

EBV-positive pyothorax-associated lymphoma expresses CXCL9 and CXCL10 chemokines that attract cytotoxic lymphocytes via CXCR3

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma associated with chronic inflammation (DLBCL-CI) develops in the setting of long-standing inflammation. This type of lymphoma may have specific expression profiles of chemokines involved in the pathogenesis of DLBCL-CI. EBV-positive pyothorax-associated lymphoma (PAL) is a prototype of DLBCL-CI and represents a valuable model for the study of this disease category. Using a panel of PAL cell lines, we found that PAL cells expressed and secreted C-X-C motif chemokine ligands 9 and 10 (CXCL9 and CXCL10), the ligands of CXCR3, in contrast to EBV-negative DLBCL cell lines, which did not. Culture supernatants from PAL cell lines attracted CXCR3-expressing CD4⁺ T cells, CD8⁺ T cells, and CD56⁺ natural killer cells from human peripheral blood mononuclear cells. PAL cells injected into mice also attracted CXCR3-positive cytotoxic lymphocytes that expressed interferon-γ. The expression of CXCL9 and CXCL10 was detected in PAL tumor biopsy samples from patients, and CXCR3-positive lymphocytes were abundant in the tissue samples. Collectively, these findings suggest that CXCL9 and CXCL10 are produced by PAL cells and can elicit cytotoxic responses via CXCR3. This chemokine system is also likely to contribute to tissue necrosis, which is a signature histological feature of DLBCL-CI. Further studies are warranted to determine whether the CXCL9-CXCL10/CXCR3 axis exerts antitumor effects in DLBCL-CI.

Metagenomic next-generation sequencing for pleural effusions induced by viral pleurisy: A case report

BACKGROUND

Viral pleurisy is a viral infected disease with exudative pleural effusions. It is one of the causes for pleural effusions. Because of the difficult etiology diagnosis, clinically pleural effusions tend to be misdiagnosed as tuberculous pleurisy or idiopathic pleural effusion. Here, we report a case of pleural effusion secondary to viral pleurisy which is driven by infection with epstein-barr virus. Viral infection was identified by metagenomic next-generation sequencing (mNGS).

CASE SUMMARY

A 40-year-old male with a history of dermatomyositis, rheumatoid arthritis, and secondary interstitial pneumonia was administered with long-term oral prednisone. He presented with fever and chest pain after exposure to cold, accompanied by generalized sore and weakness, night sweat, occasional cough, and few sputums. The computed tomography scan showed bilateral pleural effusions and atelectasis of the partial right lower lobe was revealed. The pleural fluids were found to be yellow and slightly turbid after pleural catheterization. Thoracoscopy showed fibrous adhesion and auto-pleurodesis. Combining the results in pleural fluid analysis and mNGS, the patient was diagnosed as viral pleuritis. After receiving Aciclovir, the symptoms and signs of the patient were relieved.

CONCLUSION

Viral infection should be considered in cases of idiopathic pleural effusion unexplained by routine examination. mNGS is helpful for diagnosis.

Epstein-Barr virus-positive pyothorax-associated lymphoma expresses CCL17 and CCL22 chemokines that attract CCR4-expressing regulatory T cells

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphomas associated with chronic inflammation (DLBCL-CI) develop in patients with chronic inflammation but without any predisposing immunodeficiency. Given the expression of the EBV latent genes, DLBCL-CI should have mechanisms for evasion of host antitumor immunity. EBV-positive pyothorax-associated lymphoma (PAL) is a prototype of DLBCL-CI and may provide a valuable model for the study of immune evasion by DLBCL-CI. This study demonstrates that PAL cell lines express and secrete CCL17 and/or CCL22 chemokines, the ligands of C-C motif chemokine receptor 4 (CCR4), in contrast to EBV-negative DLBCL cell lines. Accordingly, culture supernatants of PAL cell lines efficiently attracted CCR4-positive regulatory T (Treg) cells in human peripheral blood mononuclear cells. PAL cells injected into mice also attracted CCR4-expressing Treg cells. Furthermore, this study confirmed that CCR4-expressing Treg cells were abundantly present in primary PAL tissues. Collectively, these findings provide new insight into the mechanisms of immune evasion by PAL, and further studies are warranted on whether such mechanisms eventually lead to the development of DLBCL-CI.

Primary diffuse large B-cell lymphoma as a chest-wall mass: A case report

RATIONALE

Primary diffuse large B-cell lymphoma of the chest wall is extremely rare. A majority of the pleural lymphomas develop in patients with chronic tuberculous pyothorax. The underlying mechanism might be attributed to the sustained stimulation of chronic inflammation. Surgery followed by adjuvant chemotherapy can improve the outcome in some patients with lymphoma localized only in the chest wall. Thus, an early diagnosis of pyothorax-associated lymphoma is essential as it is a malignant, life-threatening condition.

PATIENT CONCERNS

A 79-year-old male complained of left-side chest pain for more than 2 months, which was not alleviated with nitrates and aspirin. The patient presented an intermittent low fever, anorexia, and marasmus, accompanied by tuberculosis 40 years ago and chronic left-side pyothorax. Also, ANCA (antineutrophil cytoplasmic autoantibody)-associated vasculitis occurred for >3years.

DIAGNOSIS

Computed tomography scan showed a solid mass in the left lateral chest wall. The patient underwent ultrasonic-guided biopsy of the lesion. A diagnosis of primary diffuse large B-cell lymphoma of the chest wall was established after histological examination.

INTERVENTION

Due to advanced age and poor physical condition, the patient received CHOP chemotherapy at a reduced dose.

OUTCOMES

The patient died 5 days after the first cycle of chemotherapy with severe dyspnea and high fever.

LESSONS

The chronic inflammation stimulation might result in the development of lymphoma in the chest wall of patients with long-term pyothorax, vasculitis, or other autoimmune diseases associated with malignancies. The fever, chest pain, or other nonspecific clinical symptoms in these patients should be under intensive focus as it might indicate the development of malignant lymphoma. Thus, histological examination in these patients is essential for accurate early diagnosis.

Fibrin-associated EBV-positive Large B-Cell Lymphoma: An Indolent Neoplasm With Features Distinct From Diffuse Large B-Cell Lymphoma Associated With Chronic Inflammation

Incidental cases of localized fibrin-associated Epstein-Barr virus (EBV)+ large B-cell proliferations have been described at unusual anatomic sites and have been included in the category of diffuse large B-cell lymphoma associated with chronic inflammation (DLBCL-CI) in the WHO Classification. We describe 12 cases and review the literature to define their clinicopathologic spectrum and compare features with typical cases of DLBCL-CI. Median age was 55.5 years with a M:F ratio of 3. In all 12 cases, the lymphoma was an incidental microscopic finding involving atrial myxomas (n=3), thrombi associated with endovascular grafts (n=3), chronic hematomas (n=2), and pseudocysts (n=4). All cases tested were nongerminal center B-cell origin, type III EBV latency, and were negative for MYC rearrangements and alternative lengthening of telomeres by FISH. Most showed high CD30, Ki67, and PD-L1, and low to moderate MYC and p53 expression. Among 11 patients with detailed follow-up, 6 were treated surgically, 3 with cardiac or vascular lesions had persistent/recurrent disease at intravascular sites, and 4 died of causes not directly attributable to lymphoma. Reports of previously published fibrin-associated cases showed similar features, whereas traditional DLBCL-CI cases with a mass lesion had significantly higher lymphoma-associated mortality. Fibrin-associated EBV+ large B-cell lymphoma is clinicopathologically distinct from DLBCL-CI, warranting separate classification. Most cases, particularly those associated with pseudocysts, behave indolently with the potential for cure by surgery alone and may represent a form of EBV+ lymphoproliferative disease rather than lymphoma. However, primary cardiac or vascular disease may have a higher risk of recurrence despite systemic chemotherapy.

EBV-Positive B-Cell Proliferations of Varied Malignant Potential: 2015 SH/EAHP Workshop Report-Part 1

OBJECTIVES

The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review B-cell proliferations of varied malignant potential associated with immunodeficiency.

METHODS

The Workshop Panel reviewed all cases of B-cell hyperplasias, polymorphic B-lymphoproliferative disorders, Epstein-Barr virus (EBV)-positive mucocutaneous ulcer, and large B-cell proliferations associated with chronic inflammation and rendered consensus diagnoses. Disease definitions, boundaries with more aggressive B-cell proliferations, and association with EBV were explored.

RESULTS

B-cell proliferations of varied malignant potential occurred in all immunodeficiency backgrounds. Presentation early in the course of immunodeficiency and in younger age groups and regression with reduction of immunosuppression were characteristic features. EBV positivity was essential for diagnosis in some hyperplasias where other specific defining features were absent.

CONCLUSIONS

This spectrum of B-cell proliferations show similarities across immunodeficiency backgrounds. Localized forms of immunodeficiency disorders arise in immunocompetent patients most likely due to chronic immune stimulation and, despite aggressive histologic features, often show indolent clinical behavior.

Recent Advances in Aggressive Large B-cell Lymphomas: A Comprehensive Review

Diffuse large B-cell lymphoma (DLBCL) is an aggressive disease with considerable heterogeneity reflected in the 2008 World Health Organization classification. In recent years, genome-wide assessment of genetic and epigenetic alterations has shed light upon distinct molecular subsets linked to dysregulation of specific genes or pathways. Besides fostering our knowledge regarding the molecular complexity of DLBCL types, these studies have unraveled previously unappreciated genetic lesions, which may be exploited for prognostic and therapeutic purposes. Following the last World Health Organization classification, we have witnessed the emergence of new variants of specific DLBCL entities, such as CD30 DLBCL, human immunodeficiency virus-related and age-related variants of plasmablastic lymphoma, and EBV DLBCL arising in young patients. In this review, we will present an update on the clinical, pathologic, and molecular features of DLBCL incorporating recently gained information with respect to their pathobiology and prognosis. We will emphasize the distinctive features of newly described or emerging variants and highlight advances in our understanding of entities presenting a diagnostic challenge, such as T-cell/histiocyte-rich large B-cell lmphoma and unclassifiable large B-cell lymphomas. Furthermore, we will discuss recent advances in the genomic characterization of DLBCL, as they may relate to prognostication and tailored therapeutic intervention. The information presented in this review derives from English language publications appearing in PubMed throughout December 2015. For a complete outline of this paper, please visit: http://links.lww.com/PAP/A12.

Cutaneous Lymphoma at Injection Sites

Feline primary cutaneous lymphomas (FPCLs) account for 0.2% to 3% of all lymphomas in cats and are more frequently dermal nonepitheliotropic small T-cell tumors. Emergence of FPCL seems unrelated to feline leukemia virus (FeLV) serological positivity or to skin inflammation. A total of 17 cutaneous lymphomas with a history of vaccine injection at the site of tumor development were selected from 47 FPCLs. Clinical presentation, histology, immunophenotype, FeLV p27 and gp70 expression, and clonality were assessed. A majority of male (12/17), domestic short-haired (13/17) cats with a mean age of 11.3 years was reported. Postinjection time of development ranged from 15 days to approximately 9 years in 5 cats. At diagnosis, 11 of 17 cats had no evidence of internal disease. Lymphomas developed in interscapular (8/17), thoracic (8/17), and flank (1/17) cutaneous regions; lacked epitheliotropism; and were characterized by necrosis (16/17), angiocentricity (13/17), angioinvasion (9/17), angiodestruction (8/17), and peripheral inflammation composed of lymphoid aggregates (14/17). FeLV gp70 and/or p27 proteins were expressed in 10 of 17 tumors. By means of World Health Organization classification, immunophenotype, and clonality, the lesions were categorized as large B-cell lymphoma (11/17), anaplastic large T-cell lymphoma (3/17), natural killer cell–like (1/17) lymphoma, or peripheral T-cell lymphoma (1/17). Lineage remained uncertain in 1 case. Cutaneous lymphomas at injection sites (CLIS) shared some clinical and pathological features with feline injection site sarcomas and with lymphomas developing in the setting of subacute to chronic inflammation reported in human beings. Persistent inflammation induced by the injection and by reactivation of FeLV expression may have contributed to emergence of CLIS.

Epstein-Barr Virus-Positive Pyothorax-Associated Lymphoma Arising from a Posttraumatic Empyema

Pyothorax-associated lymphoma (PAL) develops from a pyothorax caused by an artificial pneumothorax created during the treatment of pulmonary tuberculosis or tuberculous pleuritis. We report the first case of Epstein-Barr virus (EBV)-positive PAL arising from a posttraumatic empyema. A 75-year-old woman with chronic posttraumatic empyema presented with a tumor, which was connected to the wall of a pyothorax in the right thoracic cavity. She had a history of trauma to the right chest, which had occurred at the age of 45 years and had caused the chronic posttraumatic empyema. Pathological features of the resected tumor were conclusive for a diagnosis of EBV-positive PAL. Although neither postoperative chemotherapy nor radiotherapy was performed, remission was maintained for 3 years until recurrence in the liver. Combination chemotherapy led to complete remission, and 9 years after the initial diagnosis of PAL, the patient is still alive. An intriguing finding is the phenotypic alteration during the disease course. Although the primary tumor was negative for CD20 and CD3, the recurrent tumor expressed both of these molecules. We discuss this case of PAL, which was not a complication of lung tuberculosis, and the aberrant chronological phenotypic change observed in the lymphoma cells, and compare it with a usual case of PAL.

Recurrent primary cardiac lymphoma on aortic valve allograft: implications for therapy

Primary malignant cardiac lymphomas associated with grafts are extremely rare: to our knowledge, only 6 cases of prosthesis-associated B-cell lymphoma have been reported. Ours is the first report of recurrent diffuse large B-cell lymphoma associated with aortic valve allografts. We treated a 60-year-old man who presented in early 2007 with aortic valve endocarditis. He underwent aortic valve replacement with an allograft; the resected native valve showed active endocarditis without tumor. In January 2011, the patient underwent repeat aortic valve replacement because of symptomatic aortic regurgitation. The explanted valve specimen displayed diffuse large B-cell lymphoma. In September 2011, the patient presented with fever and a mass around the aortic valve. He died in January 2012. On autopsy, the explanted replacement valve displayed recurrent diffuse large B-cell lymphoma. The recurrent lymphoma on a new graft leads us to believe that this tumor is more aggressive than had been thought. We propose early systemic chemotherapy, in addition to tumor resection, for the possibility of a better prognosis. We discuss our patient's case and review the relevant medical literature.

Pleuropulmonary angiosarcoma involving the liver, the jejunum and the spine, developed from chronic tuberculosis pyothorax: Multidisciplinary approach and review of literature

Pleuropulmonary angiosarcomas are very rare, with less than fifty cases reported in the literature. In most cases, the etiology is unknown but the presence of a chronic tuberculous pyothorax has been reported in several Asian case reports as a possible risk factor. We report the case of a Caucasian 68-year old man who presented with a pleuropulmonary angiosarcoma that arose from a chronic tuberculous pyothorax and which involved the ribs and the vertebrae, the psoas muscle, and the jejunum. The patient received adapted anti-tuberculosis treatment, embolization of the mass in the small bowel, palliative external beam radiotherapy on the spine and systemic chemotherapy with liposomal non-pegylated doxorubicin and ifosfamide. With this multidisciplinary approach the patient's symptoms were well controlled and he achieved a complete metabolic response after six cycles of chemotherapy. Unfortunately, the patient died after eight months from the beginning of chemotherapy due to an acute lung injury secondary to extensive bilateral interstitial infiltrates. Opportunistic pathogens or drug-induced lung toxicity were the most probable causes. Treatment with liposomal non-pegylated doxorubicin and ifosfamide could be a reasonable option in pleuropulmonary angiosarcoma but it should be validated in clinical trials. Chronic pyothorax seems to be a predisposing factor for the development of pleural angiosarcoma but further investigations are required to assess a causal association.

Viral diseases affecting the pleura

BACKGROUND

Viruses affect the human body in multiple ways producing various disease states. The infections of the pulmonary parenchyma have been well described. However, there has been no current review of the literature pertaining to the pleura.

AIM

To review the available literature pertaining to diseases of the pleura that are caused by viral infections.

METHODS

A Medline search was performed and available research and review articles relating to viral infections that resulted in pleural effusions, pleural masses, pleural thickening, and pleural nodularity were reviewed.

CONCLUSION

There are numerous viruses that cause diseases of the pleura. Pleural effusions and lesions within the pleura are the most common presentation of the disease state. Polymerase chain reaction has the potential to further diagnose viral infections and expand our knowledge base in this field.

Herpesvirus-Associated B-cell Proliferations

This article reviews the spectrum of Epstein-Barr virus and Kaposi sarcoma herpesvirus (KSHV/HHV-8)-associated B-cell lymphoid proliferations, their pathologic features and clinical presentation, diagnostic criteria, and pathogenetic aspects. Emphasis is on the differential diagnosis issues and difficulties that the pathologist may face for the correct identification and interpretation of these lesions.

Murine gammaherpesvirus 68 infection of IFNgamma unresponsive mice: a small animal model for gammaherpesvirus-associated B-cell lymphoproliferative disease

Gammaherpesviruses are tightly controlled by the host immune response, with gammaherpesvirus-associated malignancies prevalent in immune-suppressed individuals. Previously, infection of IFNgamma-unresponsive mice with gammaherpesvirus 68 (gammaHV68) showed that IFNgamma controlled chronic infection, limiting chronic diseases including arteritis and pulmonary fibrosis. Here, we show that gammaHV68-infected IFNgamma receptor-deficient (IFNgammaR(-/-)) mice uniformly develop angiocentric inflammatory lesions in the lung. Prolonged infection revealed a range of outcomes, from spontaneous regression to pulmonary lymphoma. By 12 months of infection, 80% of mice had lymphoid hyperplasia or pulmonary lymphoma; 45% of infected mice developed frank tumors between 5 and 12 months postinfection, with some mice showing systemic involvement. Lymphomas were composed of B lymphocytes and contained latently infected cells. Although IFNgammaR(-/-) mice control chronic gammaHV68 infection poorly, both early and late pathologies were indistinguishable between wild-type and reactivation-defective virus infection, indicating that, in contrast with other previously described gammaHV68-associated pathologies, these chronic diseases were not dependent on the reactivation of latent infection. This distinct combination of latent infection and defined host defect led to a specific and consistent lymphoproliferative disease. Significantly, this mouse model of virus-associated pulmonary B-cell lymphoma closely mimics the full spectrum of human lymphomatoid granulomatosis, an EBV-associated malignancy with no effective treatment.

A left knee wound complication by non-Hodgkins lymphoma in bilateral total knee arthroplasties

A 70-year-old woman with a history of bilateral primary knee osteoarthritis presented with a left knee wound complication, a non-Hodgkins lymphoma, after bilateral total knee arthroplasties. After exploring several etiologies, the evidence in this unusual case suggests a coincidental preexisting lymphoma.

Primary chest wall lymphoma with no history of tuberculous pyothorax: diagnosis and treatment

OBJECTIVE

Primary chest wall neoplasm represents only 5% of chest wall neoplasm and among them primary chest wall lymphoma is uncommon.

METHODS

A 28-year-old man had no history of tuberculous pyothorax or artificial pneumothorax therapy but did have a 4-month history of dyspnea, fever, chills, and night sweats. On physical examination, a mass about 10 x 10 cm was noted on the anterior chest wall on the right side, and computed tomographic scan demonstrated that it originated from the pleural wall. A 42-year-old man was admitted with intermittent left hemithoracic pain from about 6 months before his visit. A 5 x 5-cm tender mass in the posterior wall of the left hemithorax was palpated. Computed tomography showed mild plural effusion and erosion in the posterior segment of the left ninth rib. Surgery was performed for histologic diagnosis.

RESULTS

With the diagnosis of large B cell lymphoma, chemotherapy was prescribed for the first patient, and the patient has been in complete remission for more than 5 months. For the second patient, the left ninth rib along with the originated mass was completely resected and chemotherapy was prescribed. The patient has been in complete remission for more than 8 months.

CONCLUSION

Treatment of primary chest wall lymphoma was not clear and various treatment strategies were considered. Remission of considerable duration in our patients leads us to suggest that surgery followed by adjuvant chemotherapy can provide a reasonable outcome in patients in whom the chest wall lymphoma is the only site of disease.

Primary pleural neoplasia: entities other than diffuse malignant mesothelioma

CONTEXT

Overwhelmingly, the most common neoplasm involving the pleura is metastatic carcinoma. In contrast, diffuse malignant mesothelioma occurs relatively rarely; however, it is nonetheless the most common neoplasm primary to the pleura. Metastatic carcinoma and diffuse malignant mesothelioma each have their own prognostic and therapeutic characteristics. Other primary pleural neoplasms occur uncommonly or rarely, with their own prognostic and therapeutic characteristics.

OBJECTIVE

To review primary pleural neoplasms other than diffuse malignant mesothelioma, to better ensure correct diagnosis and optimal assessment of prognosis and treatment.

DATA SOURCES

Literature review and primary material from the authors' institutions.

CONCLUSIONS

A nonexhaustive group of uncommon to rare benign and malignant primary pleural neoplasms--other than diffuse malignant mesothelioma--are presented, of which one must be aware in order to maintain an appropriate index of suspicion to include them in the differential diagnosis of a pleural tumor.

[Primary pleural lymphoma: a late complication of pleural decortication for tuberculosis: two cases in western countries]

Pleural lymphomas after a long standing pyothorax due to pleuropulmonary tuberculosis are now well identified, but rarely observed in Europe. We report two new cases in a non-immunocompromised patients. The two cases occurred 5455 years following artificial pneumothorax for pulmonary tuberculosis. The patients presented with a localized pleural tumor mass. Histology revealed high-grade lymphomas, diffuse large B-cell lymphoma and anaplastic lymphoma. Serology for Epstein-Barr virus was positive. Pleural lymphomas are an established complication of artificial pneumothorax. Epstein-Barr virus is known to play a crucial role in the pathogenesis, but despite the large number of artificial pneumothorax operations, these lymphomas remain rare, suggesting additional oncogenic factors.

Pyothorax-associated lymphoma: a case showing transition from T-cell-rich polymorphic lesion to diffuse large B-cell lymphoma

Pyothorax-associated lymphoma was found in a man who had a history of collapse therapy for pulmonary tuberculosis about 50 years ago. An autopsy specimen revealed histology of diffuse large B-cell lymphoma with latency III Epstein-Barr virus (EBV) infection. However, an open biopsy 2 years and 7 months before death showed a polymorphic appearance with abundant T-lymphocytes. Most of the EBV-infected atypical lymphocytes did not express either B- or T-cell markers as far as examined in the paraffin-embedded biopsy specimen, and rearrangements of immunoglobulin and T-cell receptors were not found. It seemed difficult to diagnose a B-cell lymphoma at the time of biopsy. However, retrospectively considered, if a phenotype of EBV-infected atypical lymphocytes is uncertain in cases showing polymorphic appearance, it might be better to consider the future evolution to overt B-cell lymphoma. Since pyothorax-associated lymphoma shows latency III infection of EBV, at least the immunohistochemistry of EBNA-2 and LMP-1 seems helpful for the diagnosis to prove which cells are infected by EBV.

Clinicopathological features of pyothorax-associated lymphoma; a retrospective survey involving 98 patients

To investigate clinicopathological features of pyothorax-associated lymphoma (PAL), we examined medical records of 98 patients (88 males and 10 females) with PAL at a median age of 70 years (range 51-86). Seventy-nine patients had a history of artificial pneumothorax. Median interval between diagnosis and artificial pneumothorax was 43 years (range 19-64). At diagnosis, performance status (PS) was 0-1 (n=56) and 2-4 (n=42). Clinical stages were I (n=42), II (n=26), III (n=8) and IV (n=22). Pathological diagnosis comprised diffuse large-B-cell (n=78) and peripheral T-cell lymphoma (n=1). Seventeen were treated supportively. The other 81 received aggressive treatments; chemotherapy (n=52), radiotherapy (n=7), surgery (n=4) and combination (n=18). Five-year overall survival (OS) was 0.35 (95% confidence interval, 24% to 45%). Causes of deaths were PAL (n=39), respiratory failure (n=13) and others (n=12). Multivariate analysis identified prognostic factors for OS; lactate dehydrogenase levels [hazard ratio (HR)=2.36; P=0.013], sex (female versus male) (HR=0.15; P=0.01), PS (2-4 versus 0-1) (HR=2.20; P=0.02), clinical stages (III/IV versus I/II) (HR=1.95; P=0.037) and chemotherapy (HR=0.31; P=0.01). Most patients with PAL are elderly and have comorbidities, while some of them achieve durable remission with appropriate treatments. These findings prompt us to establish an optimal treatment strategy on the basis of risk stratification of individual patients.

Pyothorax-associated lymphoma

In Japan, EBV positive rate in immunocompetent patients with nodal lymphomas is less than 10% in B-cell and 20-50% in T cell lymphoma. Among extranodal lymphomas, EBV positive rate is higher in pyothorax-associated lymphoma (PAL), nasal NK/T-cell lymphoma, and adrenal lymphoma. PAL is non-Hodgkin's lymphoma that develops from chronic pyothorax resulted from artificial pneumothorax for the treatment of lung tuberculosis or tuberculous pleuritis. This disease was originally described by Dr. Aozasa as a distinctive clinicopathologic entity in 1987, and now listed as the disease entity in the WHO classification of Tumours, Pathology & Genetics, Tumours of the Lung, Pleura, Thymus and Heart (2004).

Extranodal Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue With Initial Presentation in the Pleura

Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (EMZL/MALT-type) occurs in a wide variety of body sites; it is well recognized as a form of primary lung lymphoma. However, until recently, pleural presentation of this form of low-grade lymphoma has not been documented. A small series of case reports has brought to attention the potential for primary occurrence or initial presentation in the pleura of EMZL/MALT-type. In this report, we describe an additional patient with EMZL/MALT-type with initial pleural presentation and review the literature. Clinicians and pathologists dealing with lymphoproliferative disorders involving the pleura should be aware of this rare entity.

Pyothorax-associated lymphoma: a lymphoma developing in chronic inflammation

Pyothorax-associated lymphoma (PAL) is a non-Hodgkin lymphoma of exclusively B-cell phenotype developing in the pleural cavity of patients after more than 20-year history of pyothorax resulting from an artificial pneumothorax for the treatment of pulmonary tuberculosis or tuberculous pleuritis. The most common symptoms on admission are chest pain and fever. Serum neuron-specific enolase level suggesting a diagnosis of small cell lung cancer is occasionally elevated. Histologically PAL usually shows a diffuse proliferation of large cells of B-cell type (diffuse large B-cell lymphoma [DLBL]). In PAL cells, representative B-cell markers other than CD20 are frequently negative with aberrant expression of T-cell markers such as CD2. A gene expression profile of PAL is distinct from nodal DLBL in its higher expression level of interferon-inducible genes. PAL is strongly associated with Epstein-Barr virus (EBV) infection with expression of EBV latent genes such as EBNA-2, LMP-1, together with EBNA-1. Taken together, PAL is a distinct entity both in its clinicopathologic presentation as well as its gene expression profile. Use of an artificial pneumothorax, EBV infection, and cytokines and reactive oxygen species produced in longstanding pyothorax might be important factors for PAL development.

Metallic implant-associated lymphoma: a distinct subgroup of large B-cell lymphoma related to pyothorax-associated lymphoma?

Primary non-Hodgkin lymphoma arising at the site of metallic implant is very rare, and the possible carcinogenic effects of the metallic components and wear particles of the implant have not been answered despite many years of investigation. We report a case of large B-cell lymphoma occurring in a 78-year-old man who had a knee prosthesis implant for more than 30 years. The lymphoma was of microscopic size and found incidentally in the wear debris removed at surgical revision of the loosened prosthesis. The lymphoma expressed CD20, showed clonal rearrangements of immunoglobulin gene, and harbored Epstein-Barr virus (EBV). This case, together with previously reported cases, suggests that metallic implant-associated lymphoma is a distinctive subgroup of large B-cell lymphoma that shares many similarities with pyothorax-associated lymphoma and osteomyelitis-associated lymphoma, in that the lymphoma is an EBV-associated large B-cell lymphoma arising in a setting of chronic inflammation or irritation in a confined body space.