Colorectal tubular adenomas are graded in both low-grade and high-grade categories, which can be used to guide subsequent treatment.
Colorectal adenomas are classified into tubular, choroidal, and mixed tubular-choroidal adenomas based on the amount of choroidal structure contained in the tumor tissue. Colorectal tubular adenomas are classified into low-grade and high-grade according to the altered histologic structure and the heterogeneity of cell nuclei.
Low-grade adenomas are characterized by tubular and villous changes in the histologic structure, oval or elongated rod-shaped nuclei, and upward migration of nuclei less than or equal to 75% of the height of the epithelial layer. High-grade adenomas are structurally disorganized, with loss of columnar cell morphology, loss of polarity of nuclei, and nuclei found throughout the epithelial layer, with pathologic nuclear schizophrenia. High-grade adenomas, regardless of size, require prompt management, commonly by surgical resection, and require regular follow-up.
Suspected colonic tubular adenomas, regardless of grade, require prompt medical attention to avoid delay.