Extranodal marginal zone B-cell lymphoma of the mucosa associated lymphoid tissue (MALT-lymphoma) comprises < 1% of all non-Hodgkin’s lymphomas but represents the most common form of primary pulmonary lymphoma It is considered part of the spectrum of pulmonary lymphoid lesions. MALT-lymphomas are frequently associated with rheumatologic disorders, monoclonal gammopathies, immunodeficiencies and chronic infections. Here, we present a case of pulmonary MALT-lymphoma with unusual presenting features.
A previously healthy 43 year-old man presented with left-sided chest pain. Chest radiograph showed bilateral bullous changes and nodular opacities(Fig. 1A). Chest CT scan revealed bilateral cystic changes with lower lung predominance, bilateral areas of nodular consolidation and patchy infiltrates. No pneumothorax, pleural effusion or lymphadenopathy was visualized (Fig. 1B). The patient was a cigarette smoker (30 pack years). In addition he had used marijuana on an almost daily basis during the past 20 years. He worked for a company installing floors and reported significant exposure to various glues. Furthermore the patient had been briefly exposed to welding fumes. There were no risk factors for HIV and he denied a history of intravenous drug abuse. His family history was unremarkable. He was using no medications. Examination revealed normal vital signs, a prolonged expiratory phase without wheezing, no chest wall tenderness, pleural friction rub or dullness to percussion. There was no lymphadenopathy and the remainder of his physical examination was unremarkable. Pulmonary function studies disclosed the following: FEV1 2.09L(51%) with 28% improvement following administration of albuterol, RV 3.06L (177%), DLCO 20.8(65%). There was no oxygen desaturation. Complete blood count, electrolytes, HIV serology and alpha-1-AT were unremarkable. The patient underwent wedge biopsy of middle lobe. Histologic analysis indicated pulmonary MALT-lymphoma, non-necrotizing granulomatous inflammation, and light chain accumulation without amyloid deposition on congo red staining. Other findings included paraseptal emphysema in close proximity to areas of light chain deposition (Fig. 1C-E). Cultures from lung specimens showed no evidence of infectious organisms.CT scans of abdomen and pelvis, PET scan, and bone marrow biopsy confirmed localized pulmonary disease. Initially the patient received one cycle of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone(R-CHOP). Due to localized disease and side effects associated with his chemotherapeutic regimen he subsequently received three cycles of rituximab alone. His disease remained stable throughout the last 12 months.
Pulmonary MALT-lymphomas are commonly discovered incidentally by chest imaging in clinically asymptomatic patients. The most frequent radiographic findings include solitary (17%), multifocal (79%) or bilateral 60%) nodules and infiltrates[2,3]. Air-bronchograms (90%) and bubble-like radiolucencies(50%) and cavitating nodules have been described . Our patient had bilateral focal infiltrates and nodular consolidations as well as large cystic structures with a well defined wall. Similar cystic changes have been reported in lymphoid interstitial pneumonia and other benign disorders associated with pulmonary lymphocytic infiltration. These cysts are frequently lined with respiratory epithelium. It hasbeen proposed that the cysts are caused by airtrapping secondary to a ball valve mechanism. Alternatively amyloid deposition in the setting of lymphocytic infiltration has been implicated in three radiographically identical cases. In our patient no amyloid was identified but light chain deposition was present. We surmise that light chain deposits may also be associated with cyst formation in the setting of pulmonary lymphocytic infiltration. The associated non-necrotizing granulomatous inflammation was felt to be related to the MALT-lymphoma .
MALT-lymphoma can present with the unusual feature of bilateral cystic changes in the lungs. The development of these abnormalities is potentially linked to associated light chain deposition.
Tobias Peikert, None.