What disorders affect the testes?

Congenital, acquired. Congenital:- maldescent, ectopia or absence: klinefelter's syndrome: macroorchidism with fragile xsyndrome; ovotestis in hermaphrodites & v. Rare duplication or spleno-gonadal fusion. Acquired:- hydrocele; varicocele; cancer; benign teratoma; mumps orchitis; epididymo-orchitis; testis torsion or torsion of appendix testis; trauma &/or rupture; leukemic or lymphoma infiltrate.
TNTC. Too numerous to count. Common things are varicoceles, hydroceles, hernis, orchitis epididymitis all of which affect the scrotum not the testis per se.
Variety. A variety of conditions can affect the testis. They may not decent in to the scrotal sacks from the abdomen leading to shrinkage. There is a natural decline in sperm and hormone production with age. Cysts, inflammation, trauma (with collection of clotted blood), twisting (which cuts off blood supply leading to painful necrosis) and many different types of cancers may occur.