BACKGROUND: Leptomeningeal metastases from carcinoma are still poorly understood.
OBJECTIVE: To better define the management of unique intradural extramedullary spinal metastases (IESM) from solid cancers of non-neurogenic origin, in particular regarding leptomeningeal metastasis (LM).
METHODS: We conducted a retrospective, multicenter, case-control study including 11 patients with IESM matched with 11 patients with LM. Primary endpoint was overall survival; secondary endpoints were diagnostic criteria and prognostic factors.
RESULTS: Descriptive analysis showed a clinically significant difference between IESM and LM patients regarding preexisting neurological deficit (45.5% vs 90.1%, P = .06) and malignant cells in cerebrospinal fluid (0% vs 54.5%, P = .03). The median overall survival was significantly higher for IESM patients (732 days) than for patients with LM (53 days; P < .0002). Multivariate analysis showed that preexisting neurological deficit was a negative prognostic factor for overall survival (hazard ratio: 10.2; 95% confidence interval: 1.88-102; P = .04), in contrast to functional improvement with treatment (hazard ratio: 0.01; 95% confidence interval: 0.00-0.52; P = .04). We propose the following diagnostic criteria for IESM: (1) a solid lesion located within the intradural extramedullary space, (2) the absence of other leptomeningeal lesion seen on full-spine injected magnetic resonance imaging, (3) the absence of malignant cells in cerebrospinal fluid, and (4) a histological confirmation of the metastatic nature of the lesion.
CONCLUSION: The significant difference in survival between IESM and LM suggests that they are 2 distinct evolutions of the metastatic disease. Distinguishing IESM also has therapeutic consequences because patients can benefit from a focal surgical treatment with functional improvement and extended survival.
ABBREVIATIONS: IESM, intradural extramedullary spinal metastases
LM, leptomeningeal metastasis
‡Department of Neurosurgery, Pitié-Salpétrière Hospital, Université Pierre et Marie Curie, Paris, France;
§Department of Neurosurgery, Sainte-Anne Hospital Center, Paris, France;
¶University Paris Descartes, Paris, France;
‖Centre de Lutte contre le Cancer Oscar Lambret, Lille, France;
#Department of Neurosurgery, Bicêtre Hospital, University Paris Sud, Le Kremlin-Bicêtre, France;
**Department of Neurosurgery, Beaujon Hospital, University Paris Diderot, Paris, France;
‡‡Department of Neuroradiology, Sainte-Anne Hospital Center, Paris, France;
§§Department of Neurosurgery, Caen Hospital, Caen, France
Correspondence: Johan Pallud, MD, Service de Neurochirurgie, Hôpital Sainte-Anne, 1 rue Cabanis, 75674 Paris cedex 14, France. E-mail: email@example.com
* Drs Knafo and Pallud contributed equally to this work.
Received February 13, 2013
Accepted August 01, 2013