《Slide 58.》Tubulovillous adenoma, Colon

A. Brief Descriptions：

1. The prevalence of colonic adenomas is about 20 to 30 % before age of 40, arising to 40 to 50% after age of 60.

2. Adeomatous polyps are segregated into 3 subtypes on the basis of epithelial architecture.

• Tubular adenoma: exhibit greater than 75% tubular architecture.

• Villous adenoma: contain greater than 50% villous architecture.

• Tubulovillous adenoma: contain 25 to 50% villous architecture.

B. Gross Findings：

1. Range from small, pedunculated lesions to large neoplasm that are usually sessil.

C. Micro Findings：

1. Neoplastic (adenomatous) epithelium: enlarged nuclei, hyperchromatic and elongated in shape; stratification of nuclei; varies degree of dysplasia.

2. Tubular adenoma: proliferation of adenomatous epithelium, that forms tubules (separated from each other by normal lamina propria), regular tubules with little branching or tufting.

3. Villous adenoma: growth of fine fingerlets or villi that project perpendicularly from the muscularis mucosa to the outer tip of the adenoma.

D. Others:

1. All adenomatous lesions arise as the result of epithelial proliferative dysplasia, which may range from mild to severe (as carcinoma in situ).

2. There is strong evidence that adenoma are precursor lesion for invasive colorectal adenocarcinoma. 

E. Reference：

1. Robbins Pathologic Basis of Disease, 6^th ed.  P.827 ~ 831.

 

 

【 Fig. 58-1 (LP)】The tumor compose of tubular and villous architecture.

　

 

 

【 Fig. 58-2 (LP)】Tubular adenoma: proliferation of adenomatous epithelium, that forms tubules (separated from each other by normal lamina propria), regular tubules with little branching or tufting.

　

 

【 Fig. 58-3 (LP)】Villous adenoma: growth of fine fingerlets or villi that project perpendicularly from the muscularis mucosa to the outer tip of the adenoma.

　

 

【 Fig. 58-4 (HP)】Neoplastic (adenomatous) epithelium: enlarged nuclei, hyperchromatic and elongated in shape; stratification of nuclei; varies degree of dysplasia.

　

 

 

【 Fig. 58-5 (HP)】Neoplastic (adenomatous) epithelium: enlarged nuclei, hyperchromatic and elongated in shape; stratification of nuclei; varies degree of dysplasia.