Pulmonary MALT

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RSNA Case Collection


Pulmonary MALT :
Multiple bilateral lung masses with air bronchograms and surrounding ground-glass opacities are characteristic of pulmonary Mucosa Associated Lymphoid Tissue Lymphoma (MALT) (1,2). The patient’s mild symptomatic presentation and the persistence of the consolidation/ground-glass opacities for many years make an infectious etiology unlikely. This diagnosis may also be mistaken for pulmonary adenocarcinoma due to persistence of the lesion on follow up. Differentiation between lymphoma and multifocal adenocarcinoma usually requires biopsy.

Differential diagnoses:Organizing pneumonia :
Organizing pneumonia (OP) may be suspected due to this patient's age (commonly appears in adults 40-60 years old), short (one-month) history of dyspnea, presence of productive cough, and lack of smoking history (4). Additionally, air bronchograms are findings often seen in OP along with ground-glass opacities with a peripheral, perilobular, or peribronchovascular distribution. OP is typically composed of a focal lesion containing fibrous bands, vascular bundles, and accompanying lymphadenopathy (4). Persistence of these findings over the course of multiple years and the pathology make the diagnosis of OP less likely.Invasive mucinous adenocarcinoma :
Invasive mucinous adenocarcinoma accounts for about 5%-10% of lung adenocarcinomas (3). CT findings vary widely and include air bronchograms, multiple consolidations or ground-glass opacities, multifocal, and sometimes multilobar, solid and subsolid nodules, or masses. In addition to the lack of systemic symptoms, the absence of cavitary lesions, pleural effusions, and emphysema commonly seen with this diagnosis make it less likely (3).Pneumonia :
This patient's presentation of productive cough and dyspnea as well the presence of focal consolidation and areas of ground-glass opacities raises suspicion for pneumonia. However, the persistence of these findings over a 5 year period makes infection much less likely.