HS-47 Primary leiomyosarcoma of the inferior vena cava: a case series

Leiomyosarcomas of the IVC are the most common primary malignancy of the IVC; however, these lesions are extremely rare, slow growing, present late and portend a poor prognosis. Our aim is to investigate the presentation, treatment, and outcomes and propose a new standardized anatomic and surgically relevant schematic based separation of lesions. Following IRB approval, a retrospective evaluation of all IVC leiomyosarcomas at a single institution was completed, with six identified diagnoses (2008-2021). A comprehensive literature review was also completed. The median age at diagnosis was 66.5 years (range 39-79); three patients were females and three were males (50%). Notable comorbidities were a history of smoking (33.33%), hypertension (66.67%), and hyperlipidemia (66.67%). All patients in our cohort were symptomatic. Histology from biopsy or resection revealed spindle cells arranged in fascicles, atypia, mitotic figures, and necrosis. When completed, vimentin, smooth muscle actin (SMA), and desmin IHC were positive. The mean tumor size was 8.38 cm (range 3.6-14.5). Tumor location was documented in relation to renal veins: half of the tumors arose inferior to the renal veins (n=3), half were at the level of the renal veins or directly involved the renal vein (n=3). Three lesions were FNCLCC grade 3 (high-grade; 50%), and three were FNCLCC grade 2 (intermediate grade; 50%). Neoadjuvant therapy was received by only one patient; all patients underwent resection. Surgical techniques were noted: complete resection with no reconstruction (33.3%; n=2), complete resection with reconstruction (16.67%; n=1), partial resections with patches (50%; n=3). All resections were R1. Additional organ resection was required in 66.67% of cases (n=4); no notable post-op complications or mortality occurred. Post-op treatment was received by one patient, including chemotherapy and radiation. Recurrences occurred in 50% of patients (n=3). The mean overall survival time for the entire cohort was 57.5 mo. post operation (range 12-179); for those that succumbed to their disease, mean survival was 36 mo. (range 12-72). To date, 50% of the cohort has survived (mean 79 mo.; range 27-129). Although vascular tumors prove to be surgically difficult, radical resection is still the standard of care, with malignancy-free five-year survival rates of approximately 31.4%. Due to the complexity of the surgical technique required, we propose a relevant designation of IVC to centralize the involvement of the renal veins, demarcating the three regions of above the renal veins, at the level of the renal veins, and below the renal veins.