ARRS Case of the Week


Case Authors: Maria A. Manning, MD, MedStar Georgetown University Hospital, American Institute for Radiologic Pathology


23-year-old man with enlarging painful palpable right testicular mass.


Gray-scale ultrasound image of the right testis (A) shows a 2-cm well-marginated hypoechoic mass with internal linear echoes. Color Doppler image (B) shows perfusion to the testis (cursors) without intralesional flow. Epi = epididymal, Long = longitudinal.

Differential Diagnosis

  • Adenomatoid tumor of the tunica albuginea
  • Epidermoid cyst
  • Hematoma
  • Primary testicular neoplasm (mixed germ cell tumor, seminoma, teratoma)

Correct Diagnosis: Epidermoid cyst

With rare exception, solid intratesticular masses should raise suspicion for malignancy.

Epidermoid cyst should be considered when there is no vascularity in a solid-appearing intratesticular mass, particularly when the classic central hyperechogenicity (echogenic core) with alternating hypoechoic and hyperechoic rings (onion-skin appearance) is present.

Prospective diagnosis of epidermoid cyst can allow for enucleation and prevent unnecessary orchiectomy, which has hormonal, psychologic, and reproductive ramifications.

Teaching Points

Manning MA, Woodward PJ. Testicular epidermoid cysts: sonographic features with clinicopathologic correlation. J Ultrasound Med 2010; 29:831–837

Woodward PJ, Sohaey R, O’Donoghue MJ, Green DE. Tumors and tumorlike lesions of the testis: radiologicpathologic correlation. RadioGraphics 2002; 22:189–216

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