Background: Parosteal lipomas are rare benign tumors of adipose tissue located on the cortical surface of bone. They represent only a small fraction of bone lipomas, and most reported cases are small and incidentally detected. Presentation with deep vein thrombosis (DVT) has not been described previously. Case Report: We present a 61-year-old male with acute right lower limb pain diagnosed as popliteal vein DVT. Evaluation revealed a giant 30 cm parosteal lipoma of the femur, the largest reported to date. The lesion was completely excised, and the patient made an uneventful recovery with no recurrence on long-term follow-up. Conclusion: This case describes to best of our knowledge the world’s largest parosteal lipoma and its unusual presentation with DVT. Complete surgical excision through a multidisciplinary approach is essential for cure and to prevent recurrence.