A 54-year-old male patient presented with scrotal pain of long duration more on the left side. There is also intermittent sense of heaviness of the scrotum. He provided history of operated right inguinal hernia years ago.
On local examination there is a left sided varicocele and a right sided mobile small scrotal nodule firm in consistency and non-tender.
Scrotal ultrasound revealed normal appearing right and left testes with left sided varicocele and the right sided Extratesticular intrascrotal epidermoid cyst appearing well circumscribed having a whorled appearance with a central calcific focus, giving the lesion a "target" or "onion skin" appearance.
Epidermoid cyst is benign tumor of testicles representing 1% of the testicular tumors, it has no malignant potential with no metastasis.  This tumor is true cyst full of cheesy laminated material that gives it the characteristic ultrasound feature called “onion-skin” appearance. It usually presents in the second to the fourth decades of life and is presented as a palpable non tender nodule on physical examination. Extra-testicular epidermoid cyst is extremely rare with less than 10 cases reported. There are cases showing attachment to the spermatic cord, prostate and seminal vesicles with few showing extension to the true pelvis. 
Ultrasound is the primary imaging modality and epidermoid cyst can present with multiple appearances: onion ring pattern, target appearance, solid mass with an echogenic rim or sharply defined mass with a rim of calcification.  Also, absence of internal vascular flow helps in differentiating epidermoid cyst from other solid intratesticular tumors. The MR appearance was described to have onion skin appearance with alternating high and low signal intensity rings on T1 and T2 weighted images. It also can show target appearance with central and peripheral regions showing low signal intensity and middle region showing high signal intensity on both T1 and T2 weighted images with no internal gadolinium enhancement. 
Written informed patient consent for publication has been obtained.
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