Spinal epidural metastasis as the initial manifestation of malignancy: clinical features and diagnostic approach.

The objective of our study was to delineate clinical features and specific diagnostic and therapeutic implications of spinal epidural metastasis (SEM) occurring as the initial manifestation of malignancy (IMM)-a less common event than SEM in the setting of previously established malignancy (PEM). We performed a retrospective review of the clinical histories of 337 patients seen at Mayo Clinic with a radiographically verified diagnosis of SEM between January 1, 1985, and December 31, 1993. Twenty percent of all cases of SEM occurred as SEM-IMM. Carcinoma of the lung, cancer of unknown primary site, multiple myeloma, and non-Hodgkin's lymphoma were disproportionately represented in SEM-IMM, together accounting for 78% of SEM-IMM patients and only 26% of SEM-PEM patients. Inversely, breast and prostate carcinoma contributed only 12% of SEM-IMM patients but 51% of SEM-PEM patients. Only 27% of patients with SEM-IMM had nonspecific symptoms suggesting malignancy, and in only 24% did the history or physical examination suggest the primary site of malignancy. Percutaneous needle biopsy of the vertebral lesion was diagnostic of malignancy in 18 of 19 patients (95%), and no complications ensued. Fifteen patients underwent diagnostic laminectomy with biopsy, and one had a fatal complication. Survival after the diagnosis of SEM did not differ between patients with SEM-IMM and those with SEM-PEM; the median survival was 6.6 months. SEM not uncommonly occurs as the presentation of malignancy, and often it produces the only symptoms or signs of malignancy. The great majority of neoplasms presenting with SEM are carcinomas of the lung, unknown primary lesions, and hematologic malignancies. Computed tomography-guided needle biopsy is a safe, efficacious means of diagnosing malignancy, allowing for rational diagnostic workup and staging. In most patients it obviates a diagnostic spinal surgical procedure.