Perioperative mortality of metastatic spinal disease with unknown primary: A case report and review of literature

BACKGROUND: Spinal metastases are common in patients with malignancies, but studies on those metastasized from unknown primaries are scarce due to the difficulty in treatment and the relatively poor prognosis. Knowledge of surgical complications, particularly perioperative mortality, in patients with spinal metastases from unidentified sources is still insufficient. CASE SUMMARY: A 54-year-old man with chest-back pain was diagnosed with spinal metastasis in the seventh thoracic vertebra (T7). Radiographic examinations, as well as needle biopsy and immunohistochemical tests were performed to verify the characteristics of the lesion, resulting in an inconclusive diagnosis of poorly differentiated cancer from an unknown primary lesion. Therefore, spinal surgery was performed using the posterior approach to relieve symptoms and verify the diagnosis. Postoperative histologic examination indicated that this poorly differentiated metastatic cancer was possibly sarcomatoid carcinoma. As the patient experienced unexpectedly fast progression of the disease and died 16 d after surgery, the origin of this metastasis was undetermined. We discuss this case with respect to reported perioperative mortality in similar cases. CONCLUSION: A comprehensive assessment prior to surgical decision-making is essential to reduce perioperative mortality risk in patients with spinal metastases from an unknown origin.