304 First Reported Case of Metachronous Tumours With Delayed Recurrence from The Neuroendocrine Tumour Arising in A Tailgut Cyst

Abstract Background Malignant transformation of tailgut cysts (benign retrorectal cysts) into Neurodendocrine tumours (NETS) is extremely rare with less than 30 reported cases in the literature. A tiny proportion these report early recurrence (within 2 years) and to our knowledge none have delayed 6 years after primary resection. Case history We a 55-year-old male who underwent laparoscopic excision 5 cm presacral tumour found incidentally confirmed histologically be G1 NET (WHO Classification) arising from pre-existing tail gut cyst, no evidence metastasis.16 months later patient presented bowel obstruction secondary adenocarcinoma colon at splenic flexure. The left hemicolectomy; histology confirming moderately differentiated (TNM stage pT3pN0). adjuvant chemotherapy post-operatively based upon immunohistochemistry. was followed up for both CEA, serum chromogranin A, colonoscopies, CT scans. At 5th year post hemicolectomy, scan revealed new asymptomatic 18 mm internal iliac lymph node which avid on octreotide consistent metastasis resected previously. He, therefore, 30Gy sabre radiotherapy. Conclusions There consensus regarding follow duration recurrent picked as part 5-year colorectal unit. would not been identified had this metachronous case. Thus, consideration must given radiological biochemical resections.