Abstract: A 73-year-old housekeeper with asthma and hypertension presented with dyspnea and weight loss. Contrast-enhanced computed tomography of the chest revealed a new amorphous soft-tissue density in the left chest (Fig 1A, arrow), which had been absent on scan 6 years earlier (Fig 1B). The patient underwent an exploratory laparotomy. The intraoperative findings included an incarcerated Bochdalek hernia containing a splenic flexure mass. There was diaphragmatic, mesenteric, and appendiceal tumor studding. The hernia was reduced, and the diaphragm was repaired primarily. An extended left colectomy with Hartmann’s procedure, colostomy, splenectomy, and appendectomy were performed. The gross specimen image is seen in Figure 2 (arrow on mass). The final results of pathologic examination were consistent with a high-grade primary peritoneal serous carcinoma (Fig 3). In this medium magnification view, infiltrating solid nests of tumor cells (black arrow) show significant nuclear pleomorphism, hyperchromasia, and increased mitotic activity with areas of central necrosis (white arrow). After 4 months of palliative carboplatin and taxol, the patient is alive at 7 months.Fig 2View Large Image Figure ViewerDownload (PPT)Fig 3View Large Image Figure ViewerDownload (PPT)