Lung granuloma mimicking pulmonary arteriovenous malformation: Report of a case

INTRODUCTION: While hypervascular lesions in the lung are known to mimic pulmonary arteriovenous malformation (PAVM), here we report a rare case of lung granuloma mimicking PAVM, on which video-assisted thoracic surgery (VATS) was performed. PRESENTATION OF CASE: A 76-year-old woman without any symptom was admitted to our hospital because of abnormal shadow in the left lung field on chest X-ray. A 20 mm × 14 mm nodule with well-defined margins and smooth contours in the left upper segment was detected in her chest computed tomography (CT). Contrast-enhanced three-dimensional CT (3D-CT) revealed an enhanced solitary lung nodule, which was connected with linear structures suggestive of feeding artery and drainage vein. Thus, we made a preoperative diagnosis of PAVM by performing partial pulmonary resection by VATS. Intraoperatively, elastic hard nodule was palpable in the left upper segment and bruit was not convincing. Histopathological findings revealed multiple foci of coagulative necrosis surrounded by epithelioid cell granuloma containing Langhans-type multinucleated giant cells, involving the medium-sized blood vessels in the pulmonary parenchyma. Abnormal vascular structures, such as PAVM were not convincing. Based on these findings, a diagnosis of left lung granuloma was made. DISCUSSION: Preoperatively, it was difficult to distinguish the left lung granuloma from PAVM, because hypervascular lesion, such as inflammatory changes can present as strongly enhanced nodules after injection of contrast material. CONCLUSION: Surgical approach seems appropriate, not only for the purpose of diagnosis, but also for the safety in treatment of a PAVM.