Primary extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue with multiple pure ground-glass opacities: a case report

BACKGROUND Primary pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma is a low-grade B cell lymphoma that is a type of non-Hodgkin lymphoma and a type of primary pulmonary malignant lymphoma. MALT lymphomas affecting the lung show various findings on chest computed tomography, which range from typical nodules or areas of consolidation to findings that are extremely rare in pulmonary MALT lymphomas, such as pure ground-glass opacities throughout the lung. CASE PRESENTATION A 35-year-old woman was found to have a few shadows with ground glass opacities on chest computed tomography (CT) in 2012. A shadow in right S10 that was initially very small increased in size over time, and was 14 × 8 mm in 2015. Other shadows also appeared. Because lung adenocarcinoma was suspected, the patient underwent video-assisted thoracoscopic surgery with a right wedge resection of the lower lobe that included the largest nodule in S10 and other nodules. Histopathological examination of the right S10 and other lesions revealed small- or medium-sized lymphocyte-like cells that were located in the alveolar interseptal spaces. The alveolar walls remained intact. Immunohistochemical staining showed that tumor cells were positive for CD20, CD79a, and BCL2 expression. The lesions were diagnosed as extranodal marginal zone B-cell lymphoma of MALT. CONCLUSIONS We think that the ground glass opacities on CT were accounted for by MALT lesions that contained intact alveolar air spaces. The patient has remained well during 12 months of follow up after surgery. Although she did not receive chemotherapy because the MALT lymphoma lesions have been stable without progression, the patient is kept under close observation because of potential progression of the disease.