Figure 1. Well circumscribed clean-based ulcers throughout the esophagus, measuring 2-3 mm with slightly raised borders.

Prolonged survival and durable responses in several late-stage cancers such as melanoma and lung cancer have been made possible with the use of immune checkpoint inhibitors targeting the programmed cell-death protein 1 (PD-1) or its ligand PD-L1. While it is prudent to focus on the unprecedented and durable clinical responses, there are subsets of cancer patients that do not respond to immunotherapies or respond early and then relapse later. Many pathways of resistance have been characterized, and more continue to be uncovered. To overcome the development of resistance, an in-depth investigation is necessary to identify alternative immune receptors and signals with the overarching goal of expanding treatment options for those with demonstrated resistance to PD1 checkpoint immunotherapy. In this mini-review, we will discuss the mechanisms by which tumors exhibit resistance to anti-PD-1/PD-L1 immunotherapy and explore strategies to overcome such resistances.

IntroductionLeiomyosarcomas (LMS) involving the inferior vena cava (IVC) is a clinically rare entity, accounting for approximately 0.5% of all adult sarcomas.Case presentationA 67-year-old male presented to the emergency department with mild back and lower abdominal pain. During the workup, a computed tomography scan without contrast showed an area of decreased attenuation within the liver adjacent to the intrahepatic IVC. Magnetic resonance imaging confirmed the involvement of the retro-hepatic IVC; biopsy confirmed the diagnosis of LMS. Given the location of the involvement of the retro-hepatic IVC, liver explantation was deemed necessary for adequate tumor resection. The superior extension of the tumor toward the heart necessitated Cardio-Pulmonary (CPB). The patient successfully underwent a complex surgical procedure involving liver explantation with ex vivo back-table resection of the retro-hepatic LMS, replacement of the retro-hepatic vena cava with a ringed Gore-Tex graft, liver re-implantation, and hepatic vein-atrial reconstruction under cardiopulmonary bypass. There were no intraoperative or post-op complications.DiscussionThe role of vascular reconstruction of the IVC varies depending on the level and extent of the tumor, with options ranging from primary repair, ligation, or reconstruction dictated. Surgical resection with negative margins remains the treatment of choice due to the lack of efficacy of adjuvant therapies. Importantly, liver explantation offers a chance for complete surgical resection and reconstruction. Similarly, the complex nature of the tumor necessitated a pioneering approach involving direct hepato-atrial venous anastomosis.ConclusionTo the best of our knowledge, this is the first reported case in which the hepatic veins were anastomosed directly to the right atrium while also replacing the native vena cava with a separate graft.