PMC3278376_01
Radiological findings. A: Chest X-ray showed a mass shadow in the right middle lung field. B, C: Chest CT showed a tumor with an irregular border centered in the hilar region extending from S6 to the middle lobe of the right lung. Stenosis and occlusion of the pulmonary artery were found on mediastinal window setting. D: Positron emission tomography showed fluorodeoxyglucose uptake in the tumor. E: Angiography showed complete occlusion of the pulmonary trunk at the periphery proximal to the bifurcation of the posterior ascending branch, and a filling defect at the root of this branch.
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F1
An 81-year-old woman was found to have an abnormal shadow in the right lower lung field on chest radiography for a routine health check-up (Figure 1A). Chest computed tomography (CT) showed a tumor with an irregular border centered in the hilar region extending from segment 6 (S6) to the middle lobe of the right lung (Figure 1B, C). Based on stenotic and occlusive findings of the pulmonary artery on CT scan, the tumor was considered to have directly invaded the pulmonary trunk (Figure 1B, C). Although positron emission tomography showed fluorodeoxyglucose uptake with a maximum standard uptake value of 4.7 in the tumor region (Figure 1D), there was no fluorodeoxyglucose uptake in mediastinal lymph nodes or other organs. To closely examine the extent of proximal intravascular tumor invasion, angiography was performed, which revealed complete occlusion of the pulmonary trunk at the periphery proximal to the bifurcation of the posterior ascending branch, and a filling defect at the root of this branch (Figure 1E).
Surgical findings. A: Intraoperative treatment for blood vessels. The tumor invaded the pulmonary trunk on the interlobar surface and also at the root of the posterior ascending branch. The branch was ligated and divided on the peripheral side. The pulmonary trunk was clamped with vascular forceps at the periphery proximal to the bifurcation of the anterior trunk, and the pulmonary trunk was then divided and sutured. The red area indicates the cancer invasion site. The brown area indicates the thrombus in the pulmonary artery. The double lines indicate the division sites of blood vessels. B: Macroscopically, the cancer showed continuous invasion of the pulmonary artery, and the pulmonary trunk was occluded with a massive thrombus.
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F2
Massive induration was felt inside the pulmonary artery at the cancer invasion site (Figure 2A). Thus, it was ligated and divided on the peripheral side (Figure 2A). As a result of these procedures on blood vessels, we were able to preserve the right upper lobe and perform middle and lower lobectomy (Figure 2A). Gross examination of the specimen disclosed that the tumor was mainly centered in the hilar region at S6, measured 40 mm, and was partially grayish inside (Figure 2B). No cancer invasion was observed at the surgical margins of either the posterior ascending branch or the pulmonary trunk (Figure 2A).
Histological findings. A, B: The center of the adenocarcinoma is mainly composed of bronchioloalveolar, solid and acinar pattern. C, D: Adenocarcinoma invasion was observed in the pulmonary artery wall. Thrombus formation was seen in the blood vessel (C, Hematoxylin and eosin staining; D, Elastica-van Gieson staining). E, F: Adenocarcinoma mainly composed of acinar pattern invaded the tunica intima of the pulmonary artery. The endothelium of the same region had been replaced by adenocarcinoma cells.
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Histopathologically, cuboidal tumor cells showed acinar, bronchioloalveolar and solid pattern with central fibrotic scar, leading to the diagnosis of adenocarcinoma with mixed subtypes (Figure 3A, B). Invasion of adenocarcinoma mainly composed of acinar pattern was observed in the pulmonary artery wall (Figure 3C, D), and the endothelium had also been replaced by adenocarcinoma cells in the same region (Figure 3E, F). Although a large thrombus was detected at the site of vessel invasion by adenocarcinoma in the pulmonary artery, there were no malignant findings in the thrombus itself (Figure 3C-F).