title: Neuroendocrine tumor arising from tailgut cyst with spinal cord tethering: case report and literature review.
abstract: BACKGROUND
  Neuroendocrine tumors (NETs) from tailgut cysts are rare; only 15 cases have been reported until now. A tailgut cyst with spinal cord tethering has not been previously reported, although both diseases are congenital anomalies in the early stage of gestation.
  
  
  OBJECTIVE
  To report a rare case of NET from tailgut cyst associated with spinal cord tethering and review the literature.
  
  
  METHODS
  Case report and literature review.
  
  
  METHODS
  We describe the clinical course of a 53-year-old man, who presented with gluteal pain and bladder dysfunction. Magnetic resonance images showed that a tumor of the sacral spinal canal extended into the retrorectal space and connected to a thickened fatty filum terminale, which was tethering the spinal cord.
  
  
  RESULTS
  Because of tumor malignancy on a computed tomography-guided biopsy and the imaging data of involvement of presacral lymph nodes, we performed total removal of the tumor. Pathologic examination revealed NET (Grade 2) arising from a tailgut cyst. The patient received somatostatin analog therapy after surgery, followed by local radiation because of the further enlargement of the lymph nodes. Later, we started everolimus therapy for the metastases to the retroperitoneal lymph nodes. He presented with no local recurrence or further disease progression at 28 months after surgery. The review indicated that tumors in Grade 2 or 3 showed progressive clinical course after surgery and three of seven patients with biopsy were misdiagnosed.
  
  
  CONCLUSIONS
  The correct preoperative diagnosis of NETs from tailgut cysts is difficult, but extremely important because Grade 2 or 3 tumors show disease progression even after surgery. Presacral congenital tumors, such as tailgut cysts, have the potential of malignant transformation into neuroendcrine tumors or adenocarcinomas. Comorbidity of spinal cord tethering and tailgut cyst suggests some relationship to common developmental errors in embryogenesis.
authors.affiliation: Department of Neurosurgery, Tokyo Women's Medical University, 8-1 Kawada-chou, Shinjuku, Tokyo, 162-8666, Japan; Department of Spinal Surgery, Kameda Medical Center, 929 Higashi-chou, Kamogawa, Chiba, 296-8602, Japan. Electronic address: tmitsuyama@nij.twmu.ac.jp.
authors.forename: Tetsuryu
authors.initials: T
authors.lastname: Mitsuyama
authors.affiliation: Department of Spinal Surgery, Kameda Medical Center, 929 Higashi-chou, Kamogawa, Chiba, 296-8602, Japan.
authors.forename: Motoo
authors.initials: M
authors.lastname: Kubota
authors.affiliation: Department of Oncology, Kameda Medical Center, 929 Higashi-chou, Kamogawa, Chiba, 296-8602, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Department of Spinal Surgery, Kameda Medical Center, 929 Higashi-chou, Kamogawa, Chiba, 296-8602, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Yuzurihara
authors.affiliation: Department of Pathology, Kameda Medical Center, 929 Higashi-chou, Kamogawa, Chiba, 296-8602, Japan.
authors.forename: Kazuei
authors.initials: K
authors.lastname: Hoshi
authors.affiliation: Department of Neurosurgery, Tokyo Women's Medical University, 8-1 Kawada-chou, Shinjuku, Tokyo, 162-8666, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Okada
mesh_terms: D000368:Aged; D003560:Cysts / Q000473:pathology; D006801:Humans; D061705:Image-Guided Biopsy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D018358:Neuroendocrine Tumors / Q000175:diagnosis*; D012447:Sacrum / Q000473:pathology; D013116:Spinal Cord / Q000473:pathology*; D014057:Tomography, X-Ray Computed
keywords: Embryologic failure; Malignant transformation; Neuroendocrine tumor; Somatostatine analogue; Spinal cord tethering; Tailgut cyst