Case Report Somatostatin Receptor Expression in Renal Cell Carcinoma—A New Front in the Diagnostics and Treatment of Renal Cell Carcinoma Anders Höög, 1,2,3,4 Magnus Kjellman, 5,6 Per Mattsson, 5,6 C.Christofer Juhlin, 3,4 Ivan Shabo 5,6 Clinical Genitourinary Cancer, Vol. -, No. -, --- ª 2018 Elsevier Inc. All rights reserved. Keywords: Computed tomography, DOTATOC, Positron emission tomography, RCC, SSTR-2 Introduction Renal cell carcinoma (RCC) accounts for w3% of all new adult malignancies. Despite surgical resection of localized disease with curative intent, the recurrence rate of RCC is  30%. RCC can metastasize to endocrine organs such as the adrenal, pancreatic, and thyroid glands. The high rates of tumor recurrence and the need to distinguish RCC metastases from primary tumors underscore the importance of postoperative surveillance. Conventional computed tomography (CT) is the standard investigation method for monitoring patients with RCC and the detection of recurrent disease. In the adrenal glands and pancreas, RCC metastases are difficult to distinguish from primary tumors in these glands compared with thyroid lesions, which often are available for cytologic examination (with or without ultrasound guidance). Adrenal and pancreatic lesions are difficult to investigate because they are located in the retroperitoneal space. It is not uncommon for patients with suspected RCC metastasis to undergo multiple CT and magnetic resonance imaging examinations and/or other relatively invasive investigations, such as CT- or endoscopic ultrasound-guided cytologic examination before the correct diag- nosis is established. Edotreotide (DOTATOC) positron emission tomography (PET) is a functional imaging study in which the radiolabeled somatostatin analogue (SSA), gallium-68 ( 68 Ga)-DOTATOC, is used as a PET ligand. 68 Ga-DOTATOC PET integrated with CT constitutes a state of the art imaging technique for the investigation and follow- up of neuroendocrine tumors (NETs). 1 68 Ga-DOTATOC is accumulated in the tumor tissue (80% within 30 minutes) and has low activity concentrations in tissues without expression of somatostatin receptors (SSRs). Hence, DOTATOC PET/CT results in high tumor to nontumor contrast and allows for the detection of small NET lesions. In single case reports, it has been shown that RCC cases can be identified using octreotide scintigraphy. To the best of our knowledge, further analysis investigating the pathophysiologic mechanisms of these observations has not been performed. In our Clinical Practice Points Clinical Practice Points  Renal cell carcinoma (RCC) has a poor prognosis and is difficult to treat because of its ability to spread asymptomatically and its resistance to chemotherapy.  In this patient series, we report that RCC metastases can be identified using gallium-68 ( 68 Ga)-edotreotide (DOTATOC) positron emission tomography/computed tomography (PET/CT).  Immunostaining of tumor tissue from primary RCC tumors and their matched adrenal, pancreatic, and thyroid metastases showed that RCC cells express membranous somatostatin receptor 2.  These findings indicate that 68 Ga-DOTATOC PET/CT can be used as a new imaging modality in manage- ment of metastatic RCC and might contribute to the development of new somatostatin analogue-based methods for the treatment of metastatic RCC. 1 Department of Pathology 2 Department of Clinical and Experimental Medicine, Medical Faculty, Linköping University, Linköping, Sweden 3 Department of Pathology, Karolinska University Hospital, Stockholm, Sweden 4 Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden 5 Endocrine and Sarcoma Surgery Unit, Department of Breast and Endocrine Surgery, Karolinska University Hospital, Stockholm, Sweden 6 Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Submitted: Mar 18, 2018; Accepted: Mar 21, 2018 Address for correspondence: Ivan Shabo, MD, PhD, Department of Molecular Med- icine and Surgery, Karolinska Institutet, Stockholm SE 171 77, Sweden E-mail contact: ivan.shabo@ki.se 1558-7673/$ - see frontmatter ª 2018 Elsevier Inc. All rights reserved. https://doi.org/10.1016/j.clgc.2018.03.011 Clinical Genitourinary Cancer Month 2018 - 1