Context: Primary inferior vena cava (IVC) leiomyosarcoma (LMS) is a rare and aggressive vascular malignancy accounting for <0.5%
of soft‑tissue sarcomas. Due to its anatomical complexity and nonspecific clinical presentation, diagnosis and management present crucial
challenges. This case series highlights surgical strategies and outcomes from a tertiary center in Sri Lanka. Methods: A cohort of six patients
with primary IVC LMS between October 2019 and March 2025 were analyzed. Data on demographics, clinical presentation, imaging, anatomical
level of IVC involvement, operative technique, histopathology, and follow‑up outcomes were collected. Statistical Analysis Used: Microsoft
SPSS Version 30 was used for statistical analysis. Descriptive statistics were used to summarize patient demographics, tumor characteristics,
surgical procedures, and outcomes. Data were analyzed using means, ranges, and proportions. Results: Strong female preponderance was
seen (83.3%) with a mean age of 51.2 years. Presenting symptoms were nonspecific, predominantly abdominal pain. Tumor distribution
included level III–IV (50%), level II (33.3%), and level I (16.7%) of the IVC. All patients underwent laparotomy; level III tumors required full
hepatic mobilization for exposure. Vascular reconstruction included primary lateral venorraphy (66.6%) and patch repair (16.7%). One patient
required nephrectomy, and one required IVC tumor thrombectomy. At a mean follow‑up of 625.5 days, five patients (83.3%) demonstrated no
evidence of recurrence. One patient with an unresectable level IV tumor succumbed to hepatic venous outflow obstruction‑related complications.
Conclusions: Successful management of IVC LMS requires meticulous surgical planning, individualized vascular reconstruction, and
oncological resection. Early detection and anatomical localization with preoperative planning remain critical to augment outcomes in this
rare clinical entity.