The authors describe a patient who underwent orthotopic cardiac transplantation after an undifferentiated cardiac sarcoma was diagnosed. While receiving immunosuppressive therapy, the patient developed spinal column metastases and cauda equina syndrome requiring surgical decompression and stabilization. This occurred despite an exhaustive search for metastatic disease prior to the transplantation. To the authors' knowledge, this represents the first reported case of an undifferentiated cardiac sarcoma metastasis to the spine. This previously healthy 18-year-old woman presented with a myocardial infarction. Investigations revealed a left atrial tumor, which was resected. Following local recurrence, the patient underwent extensive studies to rule out systemic disease. Orthotopic heart-lung transplantation was then performed. While receiving postoperative immunosuppressive therapy the patient presented with cauda equina syndrome secondary to metastatic tumor compression at the L-5 level. Despite a comprehensive screening process to exclude metastatic disease prior to transplantation, spinal metastases occurred while this patient was receiving immunosuppressive therapy. This represents a previously unreported and clinically significant complication for undifferentiated cardiac sarcoma.