Primary well differentiated neuroendocrine tumor of the filum terminale. Case report and literature review

To present a case of a well-differentiated primary intradural-extramedullary neuroendocrine tumor of the filum terminale and to conduct a literature review. A 68-years old patient was assessed after presenting lower back pain and sciatica with ineffective pain relief. The patient presented an intradural-extramedullary lumbar lesion arising from the filum terminale, which was partially resected. The pathology diagnosis was a well-differentiated primary neuroendocrine tumor (carcinoid tumor). After a multidisciplinary evaluation, fractionated stereotactic radiotherapy was administered. No progression or metastatic spread was observed in successive assessments. Neuroendocrine tumors are heterogeneous neoplasms derived predominantly from enterochromaffin cells, in which chemotherapy plays a very limited role. In contrast, radiotherapy has been described in partially resected lesions. Well-differentiated primary neuroendocrine tumors with intradural-extramedullary lumbosacral location are an exceptional rarity. Isolated surgical resection, or associated with an adjuvant radiotherapy treatment in subtotal resections, could be considered an effective therapeutic strategy.