A 1.8cm liver lesion should not be related to rectal bleeding
, unless it ruptures into the bile ducts and cause "hemobilia". This can happen with large malignant tumors.
You should get a colonoscopy for further evaluation, and maybe an upper endoscopy
, depending on your clinical history. If you have cirrhosis, you are risk of having esophageal varices
that can bleed abruptly, giving rectal bleeding.
The fact that you are having lower abdominal pain would make me think you have some sort of colon inflammation, either infectious, inflammatory bowel disease
, diverticulitis or other.