Tissue Biopsy for HPV Biopsy follows colonoscopy. When colonoscopy reveals abnormal areas then biopsy is recommended. Biopsy shows pre-malignant status or dysplasia. It can be mild, moderate and severe. Excisional biopsy is recommended when colonoscopy demonstrates high grade abnormality or low grade abnormality with severe dyskaryosis. It confirms wether genital warts are indurated, ulcerated or pigmented.