hydr- o -cel--e - Accumulation of serous fluid in a saclike structure (fluid swelling); A hydrocele is an abnormal collection of clear, straw-colored serous fluid within a saclike cavity, most commonly surrounding one or both testicles in the scrotum (hydrocele testis), but also possible along the spermatic cord or (rarely) in females via the canal of Nuck. It arises from congenital patency of the processus vaginalis (allowing peritoneal fluid entry), impaired fluid absorption, inflammation, trauma, infection (e.g., filariasis), or secondary to testicular pathology; communicating types fluctuate with activity, while noncommunicating remain fixed—most resolve spontaneously in infants, but persistent cases may require hydrocelectomy.