A boy aged 3 years with an unremarkable history was referred to the paediatric dermatology clinic for assessment of perineal lesions present from birth. The physical examination revealed several small confluent cysts in a string of pearls arrangement over the midline of the penis extending from the distal end through the ventral raphe to the perianal region (Fig. 1). The lesions were asymptomatic and showed no signs of infection. An ultrasound scan of the kidney, urinary tract and the largest lesion was performed in which the lesion appeared hypoechoic with posterior enhancement.

Figure 1.

Cystic lesions in a pearl string arrangement along the midline of the raphe.

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Given the characteristics of the lesions and the absence of additional abnormalities on imaging, the patient received a final diagnosis of perineal median raphe cysts. Median raphe cysts are a rare congenital defect of the male genitals.1 They are usually found between the urethral meatus and the perianal region, and the diagnosis is clinical.1 They are considered a developmental defect resulting from the abnormal fusion of urethral folds into the genital tubercle in the foetus.2 Most cases are asymptomatic, and the most frequent complication is overinfection.2 Although this defect is benign, the first-line treatment is surgical correction with the aim of preventing complications.3