RECURRENT METASTATIC LARGE CELL NEUROENDOCRINE CARCINOMA OF CAECUM SD Cheah1, Mohd Nizam Md Hashim1, Andee Dzulkarnaen Zakaria1, Hasmah Hussin1  1 Universiti Sains Malaysia, Kelantan, Malaysia Introduction Neuroendocrine carcinoma of the colon is rare, comprising 0.6% cases of colorectal cancer and only 0.2% out of these is of the large cell type (1) . In the large bowel, the most frequent site is the rectum, followed by the cecum and sigmoid (2) . The WHO 2010 classification has provided a new grading criteria. All well-differentiated neoplasms are called NETs and graded grade 1 (G1) (mitotic count, <2/10 high-power field [HPF] and/or ≤2% Ki-67 index) or G2 (mitotic count, 2-20/10 HPF and/or 3%-20% Ki-67 index). All poorly differentiated neoplasms are named neuroendocrine carcinomas (NECs) and graded G3 (mitotic count, N20/10 HPF and/or >20% Ki-67 index)(3) . Case Report A 45 year old man, underwent a right hemicolectomy at a private hospital. It was a neuroendocrine tumor, with involvement of lateral margin on the resected specimen. A staging CT scan did not show metastasis. However, this patient defaulted oncology referral and presented to us one year after the operation with a right lumbar mass. Serum Chromoganin A was elevated, and a colonoscopy showed recurrence at the anastomotic site. Staging CT scan showed liver and lung metastases. We performed a resection of the recurrent tumor and right nephrectomy as it was invaded. Postoperative recovery was complicated by superficial surgical site infection. Histopathology of resected tumor showed malignant cells arranged in clusters, trabeculae and nests with necrotic areas. These cells are large, having pleomorphic vesicular nuclei, prominent nucleoli and granular cytoplasm. Mitoses are seen >20/10 HPF and >20% Ki-67. He is currently undergoing chemotherapy. Discussion Large bowel NEC has a very poor prognosis . These tumors are poorly differentiated and are characterized by early dissemination and rapid clinical deterioration. The commonest site of metastasis is liver (2) . This case highlights the rarity and aggressiveness of large cell neuroendocrine tumors, with no established management protocols. For caecal NETs, surgical excision along oncological principles is the main treatment modality. Somatostatin analogs and Interferon alpha are commonly used to control symptomatic carcinoid syndrome. More recently, VEGF inhibitors and mTOR inhibitors are introduced and may lead to improved outcome in advanced and metastatic NETs (1) . References J. Philip Boudreaux et al. The NANETS consensus guideline for the diagnosis and management of neuroendocrine tumors .Pancreas & Volume 39, Number 6, August 2010 E.Aytac,Y.Ozdemir,G.Ozuner. Long term outcomes of neuroendocrine carcinomas (high-grade neuroendocrine tumors) of the colon,rectum, and anal canal Journal Of Visceral Surgery (2014) 151 , 3—7 E. Pasaoglu et al. Comparison ofWorld Health Organization 2000/2004 andWorld Health Organization 2010 classifications for gastrointestinal and pancreatic neuroendocrine tumorsAnnals of Diagnostic Pathology (2015) . http://dx.doi.org/10.1016/j.anndiagpath.2015.01.001