Case Report 611 Vol. 19, No. 7, 2005 Annals of Nuclear Medicine Vol. 19, No. 7, 611–615, 2005 CASE REPORT Received November 15, 2004, revision accepted June 27, 2005. For reprint contact: Mahmut Yüksel, M.D., T.U. Medical Faculty, Department of Nuclear Medicine, 22030 Edirne, TURKEY. E-mail: mahmuty@trakya.edu.tr INTRODUCTION CARCINOID TUMORS are neuroendocrine neoplasms that arise from the bronchus, appendix, small intestine, colon, rectum, larynx, thymus, kidney, ovary, prostate and skin. 1 They are mostly located in the appendix and ileum, 2 and often metastasis to the liver. Although functioning carci- noid tumors can be diagnosed by characteristic symp- toms and signs described as carcinoid syndrome, and by the increased serotonin metabolite 5-hydroxy-indol acetic acid (5-HIAA) in the urine, non-functioning carcinoids are found incidentally or after mechanical symptoms such as obstruction. The primary tumor and possible metastases may be localized by ultrasound, chest X-ray, gastrointestinal endoscopy, computed tomogra- phy (CT), magnetic resonance imaging (MRI), and by nuclear medicine procedures using 131 I- or 123 I-metaiodo- benzylguanidine (MIBG) and 111 In-pentetreotide in com- bination with CT and/or MRI. 3–8 The primary treatment of carcinoid tumors requires surgery as the only possible curative approach, and the success of primary surgery is closely related to patient survival. Intra-operative use of gamma probes increases the success rate of surgery with more lesions found undetected by palpation during surgery due to their smaller size. In previous series, it has been shown that by using gamma probes intraoperatively surgeons removed 57% 111 In-pentetreotide and 123 I-MIBG for detection and resection of lymph node metastases of a carcinoid not visualized by CT, MRI or FDG-PET Mahmut YU ¨ KSEL,* Samer EZIDDIN,** Elisabeth LADWEIN,*** Susanne HAAS**** and Hans-Juergen BIERSACK** *Department of Nuclear Medicine, Trakya University Medical Faculty, Edirne, Turkey **Department of Nuclear Medicine, Rheinische-Friedrich-Wilhelms University, Bonn, Germany ***Department of Surgery, Rheinische-Friedrich-Wilhelms University, Bonn, Germany ****Department of Pathology, Rheinische-Friedrich-Wilhelms University, Bonn, Germany A patient with a history of a jejunal carcinoid and resection of liver metastases underwent CT, MRI and FDG-PET as well as somatostatin receptor scintigraphy using 111 In-pentetreotide during follow-up. Octreoscan demonstrated one extrahepatic abdominal lesion with pathologic uptake, while the other imaging modalities failed to show a corresponding abnormality. For verification of this finding 123 I-MIBG scintigraphy was performed. The MIBG scan confirmed the octreotide positive lesion and showed an additional abdominal lesion in the SPECT study. According to the scintigraphic results, radioguided surgery (RGS) was implemented using 123 I-MIBG. This resulted in the intra-operative detection of two para- and pre-aortic lymph node metastases by the gamma probe and successful resection. An additional preaortal lymph node, suspicious by palpation, was also removed. Histopathology revealed metastases of a carcinoid tumor in all three specimens. In conclusion, the use of RGS facilitates successful removal of carcinoid metastatic lesions despite negative conventional imaging results. Secondly, 123 I-MIBG scintigraphy may provide advantages over octreoscan for preoperative localization as well as radio-guided surgery of neuroendocrine metastatic lesions, if the involved site is located in proximity to highly octreotide-avid organs such as the kidneys or spleen. Key words: 111 In-pentetreotide, 123 I-MIBG, radioguided surgery, carcinoid metastases, neuroen- docrine tumor