hydrocele subsides when the primary lesion resolves. Acute/chronic epididymo-orchitis Torsion of testis Testicular tumor Hematocele Filarial hydrocele Post herniorrhaphy Hydrocele of an hernial sac Infantile hydroceles It does not occur only in infants but it occurs in adults also, a hydrocele is usually an expression of a patent processus vaginalis (PPV). The tunica and the processus vaginalis are distended to the inguinal ring but there is no connection with the peritoneal cavity. Congenital hydroceles The processus vaginalis is patent and connects with the general peritoneal cavity. The communication is usually too small to allow herniation of intra-abdominal contents. Digital pressure on the hydrocele does not usually empty it, but the hydrocele fluid may drain into the peritoneal cavity when the child is lying down. Ascites or even ascitic tuberculous peritonitis should be considered if the swellings are bilateral. Encysted hydrocele of the cord There is a smooth oval swelling near the spermatic cord which is liable to be mistaken for an inguinal hernia. The swelling moves downwards and becomes less mobile if the testis is pulled gently downwards. Rarely, a hydrocele develops in a remnant of the processus vaginalis somewhere along the course of the spermatic cord. This hydrocele also transilluminates, and is known as an encysted hydrocele of the cord. In females, a related region in females, a multicystic hydrocele of the canal of Nuck sometimes presents as a swelling in the groin. It probably results from cystic degeneration of the round ligament. Unlike a hydrocele of the cord, a hydrocele of the canal of Nuck is always at least partially within the inguinal canal. The accuracy of the diagnosis must be ascertained. Great care must be taken to differentiate a hydrocele from a scrotal hernia or tumor of the testicle. Ultrasound imaging can be very useful in these cases. A hernia usually can be reduced, transmits a cough impulse, and is not translucent. A hydrocele cannot be reduced into the inguinal canal and gives no impulse on coughing unless a hernia is also present. In young children a hydrocele is often associated with a complete congenital type of hernial sac. Diagnosis A primary hydrocele is described as having the following characteristics: Transillumination positive Fluctuation positive Impulse on coughing negative (positive in congenital hydrocele) Reducibility absent Testis cannot be palpated separately. (exception - funicular hydrocele, encysted hydrocele) Treatment Most hydroceles appearing in the first year of life resolve without