Pulmonary MALT lymphoma demonstrating a crazy-paving appearance on imaging.

A 65-year-old woman was referred to our hospital due to a pulmonary nodule on chest CT. She had been diagnosed with anti-neutrophil cytoplasmic antibody-related vasculitis 10 years previously, which had been stabilized using 10 mg/ day prednisolone therapy. Chest CT revealed a crazy-paving appearance (Picture A). The lung resection specimen revealed a pulmonary low grade mucosa-associated lymphoid tissue (MALT) lymphoma (Picture C). The crazy-paving appearance refers to a pattern of linear thickening and groundglass opacities on chest CT. The infiltration of lymphoma cells resulted in interlobular septal thickening, consistent with linear thickening on chest CT (Picture B). The crazypaving appearance was initially reported to be a characteristic feature of pulmonary alveolar proteinosis. However, this feature has since been reported to present in a variety of lung diseases (1). To the best of our knowledge, this is the first report of MALT lymphoma manifesting as a crazypaving appearance, although a few reports have demon-