We report an extremely rare case of pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma with a pulmonary arteriovenous fistula (PAVF). A 60-year-old woman with vulvar carcinoma was admitted to our hospital for further examination of an abnormal shadow on chest computed tomography (CT). She showed hypoxemia in the arterial blood gas analysis. (18)F-Fluorodeoxyglucose positron emission tomography (FDG-PET) showed consolidations in the left lower lobe and soft-tissue density lesions in the anterior mediastinum. Each lesion showed heterogeneous FDG uptake. Although needle biopsy of these lesions was performed, a pathological diagnosis was not obtained. For the evaluation of hypoxemia, chest contrast-enhanced CT was performed, and a PAVF in the consolidation of the left lower lobe was revealed. For diagnostic and therapeutic purposes, we performed left lower lobectomy under video-assisted thoracoscopic surgery. In the surgical specimen the PAVF measured 3 cm, and histopathological examination revealed pulmonary MALT lymphoma adjacent to the PAVF.