Hemorrhoids are nothing but the enlarged anal cushions which are normally present.
Skin tags on the other hand can be associated with anal fissure.
Both of these do not cause cracks ( grooves) on the stool surface.
Anal fissure on the other hand can cause blood streaked stool and not grooves.
Colon cancer and polyps as such do not cause the grooves.
Grooves are seen on the surface of the stool if there is constipation.
This especially so if it is a slow transit constipation. This occurs when the transit of stool down the bowel is prolonged.
According to Bristol stool form scale, this can be categorized Type 2 or type 3 stool.
So the grooves on the stool surface is due to slow transit constipation.
Grooves are not caused by colon cancer or polyps but occurs due to constipation.
Have a colon transit study done for confirmation.
You may continue with metamucil.
Thinning can occur with constipation.
IBS is of three types diarrhea predominant, constipation predominant and mixed types.
Since there is no bleeding, no weight loss , the cahnces of colon cancer causing constipation is less likely.
As said earlier you continue with metamucil.
Since you do not have symptoms of bleeding, fatigue and weight loss, I did not ask for the family history of cancer.
Colon cancer is more common on the left colon which usually presenst with bleeding per rectum, fatigue due to anemia and altered bowel habits.
Grooves are not due to colon cancer or polyps.
But consult your doctor for evaluation of constipation.
Get back to me after your consultation with Gastroenterologist.