Left testicle removed in 2007 due to germ cell tumor now diagnosed hydrocele in remaining testicle. should i go for hydrocele surgery? any risk ?

Likely unrelated: You could have simple hydrocele ( fluid collection around testicular sac ) which is benign. Let your doctor evaluate it , yes if it is you need simple out patient surgery , will not effect your virility and safe.

Here are some...: Congratulate for surviving left testicular cancer! At to right hydrocele, one has to ask if this hydrocele significantly bothers you and if the contents inside right hemiscrotum is normally palpable or clearly seen as normal or unremarkable with ultrasound. If needed, hydrocelectomy could be well done by experienced surgeon without inadvertently injury to epididymis or vas of normal variation.