A 53-year-old man presented with concerns about swelling in his scrotum. The swelling appeared approximately three years earlier and had been increasing in size. It was painless and did not affect his walking, urination, erections, or ejaculation. He had no urethral discharge.

Physical examination revealed a left-sided scrotal mass (Figure 1) that was mobile, spongy, and ovoid. It was superior to the testicle and roughly twice the size. With the room lights turned off, an otoscope shined on the mass showed transillumination (Figure 2).

Question

Based on the patient’s history and physical examination findings, which one of the following is the most likely diagnosis?

• A. Epidermoid cyst.

• B. Hydrocele.

• C. Inguinal hernia.

• D. Testicular cancer.

• E. Varicocele.

Discussion

The answer is B: hydrocele. Hydroceles are benign masses that gradually form in the scrotum. They present as ovoid, nontender, mobile scrotal masses located superior or adjacent to the testicle. They consist of a persistent section of the processus vaginalis or tunica vaginalis and contain clear fluid. Hydroceles may appear at any age but are common in newborns, resolving in the first year of life. They are usually unilateral and appear insidiously. Hydroceles that form from a persistent processus vaginalis are situated superior to the testicle, and those that develop from the tunica vaginalis may overlap and obscure the adjacent testicle. In adults, hydroceles may result from conditions that cause lymphatic obstruction, including filariasis in tropical regions.¹