Case report: Unusual location of Dirofilaria immitis in a 28-year-old man necessitates orchiectomy

The fourth case of zoonotic Dirofilaria immitis infection in a California r esident is reported. This case was unique in that it involved the spermatic cord, produced significant symptoms, and upon physical examination was sus pected of being an incarcerated inguinal hernia. At surgery Frozen sections were inconclusive regarding neoplasia and cord involvement precluded remov al of the mass without orchiectomy, which was done. Histopathology revealed a well-preserved immature male D. immitis, the canine heartworm, in a bran ch of the spermatic artery. The morphological identification of the worm wa s confirmed by polymerase chain reaction (PCR) studies. This case illustrat es that D. immitis infections can complicate differential diagnosis of extr apulmonary Lesions and suggests that the public health significance of this vector-borne filarial worm needs to be evaluated through appropriate epide miological studies in enzootic areas.