Lobar Necrosis from Pulmonary Embolism

Abstract

Figure 1. Evaluation of the middle lobe cavity. (A) Initial chest radiograph revealed a middle lobe cavity. (B) Chest computed tomography (CT) showed the large middle lobe cavity surrounded by the medial and lateral segmental bronchi. (C) Gross tissue analysis demonstrated an occlusive thrombus in the pulmonary artery branch to the middle lobe (black arrow). Histologic analysis revealed (D) organizing thrombus within the pulmonary artery showing signs of recanalization (43 magnification), and (E) diffuse alveolar damage with loss of architecture, septal thickening, and neutrophil infiltration (103 magnification). (F) New pulmonary emboli (green arrows) were found on CT angiogram performed after resection of the middle lobe.A 63-year-old male heart transplant recipient with recurrent lower extremity deep vein thrombosis, receiving warfarin, with chronically reduced glomerular filtration rate (30 ml/min), presented with worsening cough and dyspnea. Laboratory testing revealed normal blood cell counts, mildly elevated C-reactive protein, and international normalized ratio of 1.8. Subsequent radiograph revealed a middle lobe cavity ( Figure 1A). Bronchoalveolar fluid cultures revealed Candida albicans, but antifungal therapy cleared the organism after 2 weeks. Nevertheless, the cough persisted, and the cavity progressed over the following 6 weeks ( Figure 1B). Given the uncertain etiology of the cavity and persistence of symptoms, thoracoscopic middle lobectomy was performed, during which the majority of the lobe was found to be necrotic and filled with z10 ml of thick brown liquefied debris. Major and minor fissures were "complete," preventing any collateral blood supply to the middle lobe. Gross and histological examination revealed an occlusive thrombus in the pulmonary artery branch to the middle lobe. The majority of the lobar parenchyma had undergone necrosis, leading to the cavity formation, and the walls of the cavity adjacent to the minor and major fissures revealed microscopic features of alveolar A.B.