Spinal Paradox in Suspected Thoracolumbar Metastatic Epidural Spinal Cord Compression from Recurrent HER2-Positive Breast Cancer

Abstract

Metastatic epidural spinal cord compression is a neurological emergency. Thoracolumbar involvement can produce overlapping cord and nerve-root findings, complicating localisation when degenerative lumbar disease coexists. This report describes the clinical-radiological correlation of mixed upper and lower motor neuron signs in a patient with suspected thoracolumbar metastatic epidural spinal cord compression due to recurrent HER2-positive breast cancer. A 56-year-old woman with recurrent HER2-positive left breast carcinoma developed progressive back pain, severe paraparesis, asymmetric sensory impairment, and bladder–bowel dysfunction. Examination demonstrated predominantly flaccid weakness, diminished reflexes, and bilateral extensor plantar responses. MRI showed L1 vertebral collapse and T12–L2 epidural extension compressing the distal spinal cord and conus medullaris, alongside L5–S1 disc protrusion. Mastectomy-bed ultrasonography was classified as BI-RADS 5, and biopsy reportedly supported locoregional recurrence. Spinal metastatic involvement remained clinically and radiologically suspected. Anatomical findings suggested combined spinal cord and nerve-root involvement. However, a patient-specific pathophysiological mechanism could not be confirmed. Treatment included corticosteroids, zoledronic acid, supportive care, and rehabilitation. Partial motor recovery and improvement in bladder and bowel control were reported, although objective follow-up measurements were unavailable. This case highlights the importance of clinical-radiological correlation in patients presenting with mixed upper and lower motor neuron signs. Progressive weakness and sphincter dysfunction in breast cancer survivors should prompt urgent spinal imaging and multidisciplinary evaluation, even when flaccid weakness predominates.