Pulmonary adenocarcinoma metastasis to a dorsal root ganglion: a case report and review of the literature

INTRODUCTION: The dorsal root ganglion is a rare manifestation of metastatic spread. We report what we believe to be the first case of metastasis of a pulmonary adenocarcinoma to the lumbar dorsal root ganglion. Only four descriptions for different primary tumors spreading to the dorsal root ganglion have been described in the literature so far. CASE PRESENTATION: A 70-year-old Caucasian woman with a four-month history of left-sided lumbar radiculopathy was admitted to our department under the assumption of a herniated lumbar disc. Her past medical history included a pulmonary adenocarcinoma and invasive ductal breast cancer. Lumbar magnetic resonance imaging revealed a space-occupying mass in her left neuroforamen L3-L4 with compression of her L3 nerve root. Neurinoma was taken into account as a differential diagnosis, although not considered typical. Surgery revealed a metastasis of pulmonary adenocarcinoma to her dorsal root ganglion. CONCLUSIONS: Dorsal root ganglion metastases seem to be extremely rare and can mimic primary local nerve sheath tumors. Therefore, they usually present as incidental findings. Resection should be performed strictly under intraoperative monitoring as tumor spread between the nerve fibers is commonly observed. Metastases should be taken into account in spinal nerve tumors involving the dorsal root ganglion, especially in patients harboring known malignant diseases. The low incidence means that no clear treatment advice can be given. Resection is possible under intraoperative monitoring and relieves neurological symptoms.