Intramedullary-Extramedullary Breast Metastasis to the Caudal Neuraxis Two Decades after Primary Diagnosis: Case Report and Review of the Literature.

Abstract Background Intramedullary metastases to the caudal neuraxis with exophytic extension to the extramedullary space are rare. We describe the unique case of a patient with locally recurrent breast cancer who developed an intramedullary-extramedullary metastasis to the conus medullaris and cauda equina twenty-two years after primary diagnosis, the longest interval between primary breast cancer and intramedullary spread to date. We also review the published literature on focal breast metastases to the conus medullaris or cauda equina. Case Description A 66-year-old female with a history of node-positive ER/PR-positive, infiltrating ductal carcinoma diagnosed in 1997 and locally recurrent in 2007. Initial treatment included lumpectomy and targeted chemoradiation with mastectomy and hormonal therapy at recurrence. Twelve years subsequent, she developed 6 weeks’ bilateral buttock and leg pain without motor or sphincter compromise. MRI of the total spine revealed a 2 cm x 1.7 cm bilobed intradural, intramedullary-extramedullary, homogenously enhancing, T1- and T2-isointense lesion involving the conus medullaris and cauda equina. She underwent subtotal resection of a hormone-receptor positive breast metastasis. Her pain improved postoperatively and she was stable at 5 months. Conclusion We provide evidence that patients who present with symptoms of spinal neurologic disease and a history of hormone-receptor positive breast cancer require high suspicion for metastatic pathology despite significant time lapse from primary diagnosis. The tumor may involve both the intramedullary and extramedullary space, complicating resection. Symptom relief and quality of life should guide resection of metastatic lesions to the caudal neuraxis.