Parahiatal Hernia Sac Tumor of Localized Malignant Peritoneal Mesothelioma

We describe an extremely rare case of a parahiatal hernia sac tumor. A computed tomography scan showed a solitary mass located adjacent to the diaphragm and esophagus in a 72-year-old woman. Thoracoscopic surgery revealed that a tumor protruded through a diaphragmatic defect lateral to the crus and adhered to the perigastric fat in the gastric fundus. Radical resection of the tumor and herniorrhaphy of the diaphragmatic defect were performed. Pathologic and clinical findings indicated this was a parahiatal hernia sac tumor of localized malignant peritoneal mesothelioma. No recurrence was observed without adjuvant therapy 10 months after surgery. (C) 2021 by The Society of Thoracic Surgeons