False Positive Meta-Iodobenzyl-Guanidine Scan in Testis Dermoid Cyst: A Case Report

[Introduction]This study aimed at presenting a case of testis dermoid tumor with false positive meta-iodobenzyl-guanidine (MIBG) scan.[Case Report]A 16-year-old male was referred to the urology service with bilateral testicular tumor. Testis carcinoid tumor was diagnosed after right radical orchiectomy. Although the MIBG scan was positive in left hemiscrotum before left sided operation, the left side pathology reported testis dermoid cyst.[Conclusions]Meta-Iodobenzyl-Guanidine can be absorbed by adipose tissue, one of the components of dermoid cysts. This phenomenon can result in false positivity of this scan in these cases. False negative MIBG scan is not uncommon in carcinoid tumors, however, false positive answers should not be neglected in planning treatment.