Welcome to the forum.
I agree you got some misinformation from your doctor -- or you misunderstood. All warts are caused by HPV. I can't comment on whether the lesion you are concerned about is a wart or other HPV lesion, or something entirely unrelated to HPV. However, I believe you were right to be concerned about HPV/warts. If your doctor is a proctologist or other physician who has lots of experience in anal and rectal diseases, you should speak with him again for clarification. Otherwise, you might consider getting a second opinion. As just implied, a proctologist or a surgeon who specializes in rectal and colon problems would be an excellent choice.
Anal warts and other anal HPV infections are most common by far in people who have had anal intercourse, and therefore are especially common gay men and some women. However, they are by no means rare in heterosexual men and women with no history of anal sexual exposure. Since this is apparently a new growth of some sort, I definitely recommend you follow-up as suggested above until a definite diagnosis has been made.
I hope this helps. Best wishes-- HHH, MD
Also, I should note that I'm a straight male with no history of sexual intercourse, and I have no visible growths on my penis or scrotum
Sorry, I mean no history of ANAL intercourse. I have had regular intercourse before.
I saw these comments before I replied; see above.
Thanks for your response. The doctor was a dermatologist actually. He initially prescribed mupirocin to use for 10 days, and then another medication whose name I'm forgetting to use after that if the lesion had not healed. This second medication he described as a "diagnostic treatment" -- if it works, that meant the lesion was HPV-related.
I asked about a biopsy, which I thought would be simpler and more conclusive, and he agreed to schedule one for next week.
I should have thought to say that a dermatologist also would be appropriate. The anti-wart treatment prescribed probably is imiquimod (trade names Aldara or Zyclara) or podofilox (Condylox). If the diagnosis remains uncertain, I agree a biopsy is a good idea.
So it sounds like you are in competent hands. Continue to follow the dermatologist's advice.