Primary lumbar mesenchymal chondrosarcoma mimicking a cauda equina tumor: An exceptionally rare spinal tumor

Background: Mesenchymal chondrosarcoma (MCS) is a rare, high-grade malignant tumor characterized by aggressive biological behavior, frequent local recurrence, and distant metastasis. Spinal involvement is exceedingly uncommon, with lumbar MCS representing an exceptionally rare entity; fewer than 10 cases have been reported in the literature. To the best of our knowledge, this is only the second reported case from Malaysia, with the first published in 1983. Case Description: A 19-year-old male presented with a 6-month history of progressive back pain, bilateral lower limb weakness, and sphincter dysfunction. Neurological examination demonstrated complete paraplegia with a sensory level at L2. Magnetic resonance imaging revealed a destructive L3–L4 vertebral lesion with an associated heterogeneously enhancing intradural cauda equina mass. The patient underwent posterior decompression and gross total microsurgical excision of the tumor. Histopathological and immunohistochemical findings confirmed the diagnosis of MCS. Conclusion: Lumbar spinal MCS is an exceptionally rare and aggressive malignancy with non-specific clinical and radiological features that may delay diagnosis. This case highlights the importance of maintaining a high index of suspicion for this rare entity and demonstrates that early recognition and complete surgical excision remain the cornerstone of management.