There is a 5.0 cm thin-walled hydrocele which was filled with clear straw-colored fluid. Hydrocele forms when there is fluid accumulation between the visceral and parietal layers of the tunica vaginalis. Hydrocele is lined by a single layer of cuboidal or flattened mesothelium. The reason for fluid accumulation usually is irritation of the mesothelial lining caused by hernia, scrotal trauma, epididymo-orchitis, or tumors of the testis or paratesticular region. Congenital hydrocele forms when a patent processus vaginalis in the spermatic cord communicates with the peritoneal cavity.