Lymphoproliferative lung disorders.

Although the lung is frequently involved by disseminated lymphoma, isolated pulmonary lymphoma is rare, accounting for less than 1% of all extranodal localized disease. Three broad categories of lymphoma of the lung require recognition: in rare instances, large B cell type lymphoma can present primarily in the lung; a second variant is by T cell lymphoma presenting as an angiocentric process. However, the most common histologic subtype is represented by low-grade mucosa-associated lymphoid tissue (MALT) lymphoma, often in the past considered as a pseudotumor because of its long indolent natural history. Common presenting features include cough, dyspnea, pain, fever, recurrent infections, hemoptysis, or an asymptomatic finding on routine chest radiograph. Precise pathological diagnosis and molecular characterization are required in all cases, following World Health Organization classification criteria. Radiological features include pulmonary consolidation, solid pulmonary opacities, hilar adenopathy, or pleural effusion. Principles of treatment vary with the different histology.