I had a cystoscopy for a prostatic enlargement, please advise?

I am 65 year old. I referred to the clinic for pain while urinating. I saw a drop of blood later. The urologist required a cystoscopy. The final diagnosis read “Malignant neoplasm of bladder, part unspecified 188.9”. The doctor asserts me that i have no problems with the exception of a prostatic enlargement and gave me medicine for that.
I am worried about the final diagnosis.
Can you explain this to me with some plain English?