We report the first case of Dirofilaria repens in a 4-year-old male patient in Switzerland. The disease is a vector-borne parasitic infection that is not endemic to Switzerland. A 4-year-old male presented with a tender mass in the left groin. The patient was taken to the operating room for surgical exploration to rule out a pathology that could be harmful to the spermatic cord. A node was found along the spermatic cord and excised. Histopathology and microbiology studies revealed the diagnosis of Dirofilaria repens.

Even though Switzerland is not endemic to Dirofilaria repens, the diagnosis of a parasitic infection should be considered in patients presenting with subcutaneous nodules in correlation with a travel history to endemic areas. The treatment consists of complete excision of the affected tissue.