My 13 Yr Old Son Is Feeling A Lump Above

My 13 yr old son is feeling a lump above his right testicle. He describes it as squishy and painless unless he squeezes it and the size of his normal testicles. He has been cancer free since age 2, diagnosed with stage 4 Neuroblastoma. I am reading on this site it is more likely a cyst, however, should I be more concerned due to his prior history. He was treated with chemo and surgery all between the age of 1 and 2, we did not go through with the radiation. This lump is recent and he has not complained of this before.