A case of primary pulmonary MALT lymphoma showing ground-glass nodule on chest CT

Abstract

Primary pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma is a low-grade B-cell lymphoma, and is reported as a relatively rare disease with a better associated prognosis than lung cancer. It is understood that this disease shows various imaging patterns on chest CT. Here, we report a case of pure ground-glass nodule (GGN) occurrence caused by pulmonary MALT lymphoma. A 61-year-old woman received a PET-CT check-up examination, and a pure GGN of 1.5 cm in diameter in the S4 of the left lung was detected. At the 2-year follow-up, the size of the GGN had slightly increased. We performed left upper lobectomy under video-assisted thoracic surgery because the margin of the tumor was unclear.

Microscopic examination showed small lymphocyte or plasma cell-like tumor cells that were hyperplastic and formed nodules along the alveolus. Immunohistochemically, the tumor cells were positive for both CD20 and CD79a, and immunoglobulin heavy chain gene rearrangement was detected by Southern blotting using frozen tumor sections. Finally, the patient was diagnosed with MALT lymphoma of the lung. The patient remains well with no evidence of recurrence under follow-up.