Two Case Reports Of Pulmonary Mucosa-associated Lymphoid Tissue Lymphoma And Review Of The Literature

Non-Hodgkin’s lymphoma(NHL) includes more than20kinds of entities with distinct morphology, immune phenotype, genetic and clinical characteristics. In the U.S., these lymphocytic tumors are the6th of the most common cause of death. In the past15years, the incidence of NHL has increased by50%. Mucosa-associated lymphoid tissue(MALT) lymphoma is the3rd most common NHL subtype, after diffuse large B-cell lymphoma(DLBCL) and follicular lymphoma (FL). The median age at presentation is in the sixth decade of life and there is a slight female predominance. Patients often have a history of autoimmune disease or Helicobacter pylori(Hp) gastritis. Primary pulmonary MALT lymphoma is rare, accounting for0.5%of lung tumors.In50%of cases, patients are asymptomatic with lesions discovered on routine chest radiographs. Clinical symptoms includes cough, dyspnea, chest pain, hemoptysis. The most common imaging findings is pulmonary mass, lung consolidation and multiple pulmonary nodules, air bronchogram is common. Diagnosis is confirmed by pathological diagnosis. Fine needle aspiration (FNA) biopsy in combination with immunohistochemistry is recommended. MALT lymphoma is characterized by the infiltration of small lymphocytes, marginal zone and monocytic B-cells and plasmcytes. A pivotal feature is the presence of lymphoepithelial lesions and the infiltration of centrocyte-like cells. Immunohistochemistry demonstrates that tumors cells express pan-B antigens:CD19, CD20, CD22, CD79, but they lack CD5, CD10, CD23, and Bcl-1expression. Staging requires excluding involvement outside the chest. ANN Arbor staging system is used for staging of pulmonary MALT lymphoma. Treatment includes local excision, chemotherapy or low-dose radiation therapy, when the disease is localized. Experts also have suggested "watch and wait" treatment. In this article we report two cases of pulmonary MALT lymphoma which was confirmed by percutaneous lung biopsy and systematically reviewed previous literature to illustrate the pathogenesis, clinical manifestations, diagnosis, staging and treatment aspects of MALT lymphoma.