[Pulmonary mucosa-associated lymphoid tissue(MALT) lymphoma after occupational exposure to organic solvent].

A 68-year-old woman was referred to our hospital due to a left chest abnormal shadow on chest film. She had a history of occupational exposure to organic solvent for about 30 years until 10 years ago. Computed tomography (CT) scan demonstrated a nodular shadow 12 mm in diameter in the left lower lobe. As a lung cancer was suspected, partial resection of the lobe including the small lesion was performed. Since mucosa-associated lymphoid tissue(MALT) lymphoma was diagnosed by intraoperative pathological examination, we finished the operation without any more lung resection. The diagnosis was finally confirmed by histological finding of small lymphoid cell proliferation and positive staining for CD20. Chronic inflammation, such as Helicobacter pylori infection, is considered to be a cause of MALT lymphoma. We speculate that the long term exposure to organic solvent may develop the disease by continuous chemical stimulation to bronchus.