en Oncology Oncology case report case report <div style="text-align: justify;"><span style="font-size:12pt"><span style="line-height:14pt"><span new="" roman="" style="font-family:" times=""><b><i><span style="font-size:10.0pt"><span style="color:blue">Background:&nbsp;</span></span></i></b></span></span></span><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">Carcinoid tumors of the testis&nbsp;</span></span><span style="font-size:12pt"><span style="line-height:14pt"><span new="" roman="" style="font-family:" times=""><span style="font-size:10.0pt">are rare and orchiectomy is the preferred treatment. This type of testis tumors</span> <span style="font-size:10.0pt">is rare and their differentiation from sex cord-stromal tumors is difficult.</span></span></span></span><br> <span style="font-size:12pt"><span style="line-height:14pt"><span new="" roman="" style="font-family:" times=""><b><i><span style="font-size:10.0pt"><span style="color:blue">Case presentation:</span></span></i></b> <span style="font-size:10.0pt">&nbsp;A 29‑year‑old man presented with right testicular mass and underwent radical orchidectomy.</span> <span style="font-size:10.0pt">Histological examination showed neuroendocrine tumor, confirmed by immunohistochemistry and electron microscopy</span> (<span style="font-size:10.0pt">Ethic code: IR.MUMS.REC.1400.237).</span></span></span></span><br> <span style="font-size:12pt"><span style="line-height:14pt"><span new="" roman="" style="font-family:" times=""><b><i><span style="font-size:10.0pt"><span style="color:blue">Conclusion: </span></span></i></b><span style="font-size:10.0pt">Primary testicular neuroendocrine tumor is very rare. It is crucial to submit the entire gross specimen for histopathologic examination to rule out an existing of other germ cell elements. Our patient had a well-differentiated carcinoid tumor and after two years of follow-up (every three months), there was no recurrence or metastasis.</span></span></span></span><br> <br> &nbsp;</div> neuroendocrine tumor, sex cord-stromal tumor of the testis, testicular cancer Leydig, Sertoli, and granulosa cells, testicular swelling 147 149 http://caspjim.com/browse.php?a_code=A-10-2140-1&slc_lang=en&sid=1 Ali Emadi Torghabeh emadita@mums.ac.ir 100319475328460040896 100319475328460040896 No Cancer Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Mahmoud Dovlati dolatim881@yahoo.com 100319475328460040897 100319475328460040897 No Department of Urology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Masoumeh Gharib Gharibm@mums.ac.ir 100319475328460040898 100319475328460040898 No Department of Pathology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Hamidreza Saghafi hamidrezasaghafi.md@gmail.com 100319475328460040899 100319475328460040899 No Faculty of Medicine, Tehran Medical Branch of Islamic Azad University, Tehran, Iran Mohammadreza Saghafi imansaghafi86@gmail.com 100319475328460040900 100319475328460040900 Yes Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran