Differential Diagnosis for a 31-Year-Old Male with a Scrotal Lesion

Single Most Likely Diagnosis

• Epidermoid cyst: This is a common benign lesion that can occur on the scrotum, often presenting as a firm, mobile, and sometimes tender nodule. It's a likely diagnosis given its prevalence and the fact that it can appear at any age, including in young adults.

Other Likely Diagnoses

• Sebaceous cyst: Similar to epidermoid cysts, sebaceous cysts are benign and can appear on the scrotum, presenting as a lump under the skin. They are common and can become inflamed or infected.
• Lipoma: A benign tumor composed of fat tissue, lipomas can occur almost anywhere on the body, including the scrotum. They are typically soft, movable, and painless.
• Hydrocele: An accumulation of fluid in the tunica vaginalis, a potential space around the testicle, can cause the scrotum to swell. This condition can be primary (idiopathic) or secondary to trauma, infection, or tumor.
• Varicocele: An enlargement of the veins within the scrotum, similar to varicose veins in the legs. This condition can cause a feeling of heaviness or aching in the scrotum and is more common on the left side.

Do Not Miss Diagnoses

• Testicular cancer: Although less common, testicular cancer is a critical diagnosis not to miss. It often presents as a painless testicular mass. Given the potential for serious outcomes if not treated early, it's essential to consider this in the differential diagnosis.
• Epididymitis: Inflammation of the epididymis, usually due to infection, can cause pain, swelling, and redness of the scrotum. It requires prompt treatment to prevent complications.
• Fournier's gangrene: A severe and potentially life-threatening condition characterized by necrotizing fasciitis of the genitalia. It presents with severe pain, swelling, and skin necrosis.

Rare Diagnoses

• Dermatofibroma: A rare, benign skin growth that can appear on the scrotum, though it's more commonly found on the arms or legs.
• Spermatocele: A cystic structure that forms at the head of the epididymis and contains sperm, which is a rare finding.
• Scrotal lymphangioma: A rare congenital condition that can cause scrotal swelling due to malformations of the lymphatic vessels.

Each of these diagnoses has distinct characteristics and implications for treatment, emphasizing the importance of a thorough evaluation to determine the cause of the scrotal lesion.