Sequestered Lumbar Disc Herniation Mimicking a Spinal Tumor: A Case Report.

Sequestered lumbar disc fragments are a well-recognized cause of radiculopathy; however, when disc material demonstrates contrast enhancement, it may closely resemble an intraspinal tumor on magnetic resonance imaging (MRI), leading to diagnostic uncertainty, particularly in patients with a history of malignancy. We present the case of a 75-year-old man with a history of sigmoid and prostate carcinomas who presented with persistent low back pain and right-sided radicular symptoms for two months. Neurological examination revealed no motor deficit, with preserved strength of 5/5, although intermittent paresthesia and hyperesthesia and a positive right straight-leg-raise test were present. MRI demonstrated an irregularly shaped, contrast-enhancing lateral extradural lesion at L4/L5, measuring approximately 29 × 13 × 10 mm and maintaining contact with both the anterior and posterior epidural spaces. Associated degenerative changes included loss of disc height and facet arthropathy without relevant central spinal canal stenosis. Given the patient's oncological history and the radiological appearance, an extradural spinal neoplasm was suspected. Approximately one month after MRI, a right-sided L4 hemilaminectomy was performed, and histopathological examination confirmed a sequestered lumbar disc fragment without evidence of malignancy. The patient was pain-free at discharge, and his radicular symptoms had completely resolved. At the three-month outpatient follow-up, he remained symptom-free, and no follow-up MRI was considered clinically indicated. This case highlights the importance of considering sequestered disc fragments in the differential diagnosis of contrast-enhancing extradural spinal lesions, even when the lesion is not located in an atypical epidural compartment. When imaging findings remain inconclusive, surgical exploration with histopathological confirmation may be required to establish the correct diagnosis and guide appropriate management.