Testicular epidermoid cyst

Last revised by Dr Jeremy Jones on 20 Sep 2021

Testicular epidermoid cysts, also known as keratocysts, are rare benign tumors.

Testicular epidermoid cysts account for around 1-2% of all testicular masses and typically present in mid-adulthood (2nd to 4th decades) 1,2. They are the most common type of benign testicular neoplasms 6.

The presentation can be similar to those of malignant germ cell tumors. Patients typically present with a painless and non-tender, testicular mass between 1-3 cm in diameter.

Composed of layers of keratinous debris lined with keratinizing squamous epithelium.

  • non-vascular, well-marginated intratesticular mass
  • may demonstrate a characteristic lamellated "onion skin" or "whorled" appearance with alternating hyperechoic and hypoechoic rings
  • some lesions may show a target appearance with a halo of hypoechogenicity and a central hyperechoic region

Tend to be well demarcated.  

  • T1: overall signal can be variable; may show alternating rings of high and low signal
  • T2: may a low-intensity rim 3; may also show alternating rings of high and low signal
  • T1 C+ (Gd): typically no contrast enhancement 3

These lesions are benign with no malignant potential 3.

If the diagnosis of an epidermoid is suspected at the preoperative ultrasound, the lesion can be enucleated and frozen sections obtained to confirm the diagnosis. However, treatment is controversial; some authorities advocate orchiectomy, others suggest organ-sparing surgery. 

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Cases and figures

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