Are there any eunuchs in the modern world?

Yes: Any male without testicles is essentially a eunuch. However term really refers to castration & is a male who has had his testes removed. Castration is an accepted treatment for advanced prostate cancer, is also stage in sex change from male to female. Rarely both testes have to removed for bilateral testicular cancer or torsion, where both testes or one remaining testis has lost it's blood supply.

Yes: In addition to the forms that my colleague has listed, there are others outside the law / medicine. Mutilation of young men, either voluntary or involuntary, as a punishment, a form of health quackery, or a "personal choice" is still practiced in some of our world's dark places. I have read of it even in the "enlightened" developed nations.