Practice question answers, intestinal tumors A

Practice question answers 

Intestinal tumors A

© Jun Wang, MD, PhD

1. A. This patient has iron deficiency anemia. In older population, iron deficiency anemia is often caused by chronic gastrointestinal bleeding and requires further investigation. Genetic counseling is recommended when a family history is suggestive of a genetic disorder, as seen in this patient, who might harbor BRCA mutations, a condition associated with ovarian epithelial neoplasms and breast cancers. However, this patient has no identifiable symptoms or sign of breast or ovarian neoplasm, as suggested by negative physical examination or image studies. Hemoglobin electrophoresis is used to detect hemoglobin abnormality, usually presents with anemia at childhood. Lymphocytes phenotyping may be used for primary immunodeficiency or lymphocytic neoplasms. Abnormal platelet function usually presents with petechiae.

2. B. This polyp has star-shaped lumen and no adenomatous changes (elongated hyperchromic nuclei) or significant atypia. These features are consistent with hyperplastic polyp. Adenocarcinoma has irregular glands lined by atypical cells. Juvenile polyp has cystic dilation and inflammation. Sessile serrated adenoma has features of both hyperplastic polyp and adenomatous polyp. Tubular adenoma has tubular glands lined by columnar cells with elongated hyperchromic nuclei.

3. C. Hyperplastic polyp is associated with faster proliferation with delayed shedding of surface epithelial cells. Activating mutation of beta catenin is seen in various colon and stomach adenocarcinomas. Chronic inflammation is more likely associated with inflammatory polyp. Hypermethylation of CpG island is seen in MSI abnormality associated colon cancers. Microsatellite instability associated MSI gene mutations is seen in Lynch syndrome and certain colon cancers.

4. B. Inflammatory polyp is characterized by severe acute and chronic inflammation, lack of significant atypia and a history of chronic inflammation such as inflammatory bowel disease. Adenocarcinoma has irregular glands lined by atypical cells. Sessile serrated adenoma has features of both hyperplastic polyp and adenomatous polyp. Tubular adenoma has tubular glands lined by columnar cells with elongated hyperchromic nuclei.

5. C. Juvenile polyp has cystic dilation and inflammation. When presented with multiple polyps and involving multiple organs, such as stomach in this case, is juvenile polyposis. Hyperplastic polyp has star-shaped lumen and no adenomatous changes (elongated hyperchromic nuclei) or significant atypia. Inflammatory polyp is characterized by severe acute and chronic inflammation, lack of significant atypia and a history of chronic inflammation such as inflammatory bowel disease. Peutz-Jeghers polyp is characterized by thick branching bands of smooth muscle forming a Christmas tree pattern. When multiple polyps present with cutaneous and mucosal macules, and/or family history, it is Peutz-Jegher syndrome. Sessile serrated adenoma has features of both hyperplastic polyp and adenomatous polyp.

6. D. Juvenile polyposis is associated with SMAD4 or BMPR1A mutation. APC mutation is seen in familial adenomatous polyposis. Activating mutation of beta catenin is seen in various colon and stomach adenocarcinomas. MYH mutation is seen in MYH associated polyposis (MAP), a type of familial adenomatous polyposis, and multiple colorectal adenomas. STK11 mutation is associated with Peutz-Jegher syndrome.

7. D. See discussion of question 5.

8. E. See discussion of question 6.

9. C. Tubular glands lined by columnar cells with elongated hyperchromic nuclei are consistent with tubular adenoma. Hyperplastic polyp has star-shaped lumen and no adenomatous changes (elongated hyperchromic nuclei) or significant atypia. Sessile serrated adenoma has features of both hyperplastic polyp and adenomatous polyp. Tubulovillous adenoma has features of both tubular and villous architectures. Villous adenoma is an adenomatous polyp with more than 75% of villous components.

10. E. See discussion of question 9.

11. D. See discussion of question 9.

12. B. See discussion of question 9.

13. C. MSI mutation is seen in Lynch syndrome, sessile serrated adenoma and certain colon cancers. Androgen receptor mutation is seen in prostate adenocarcinoma. Activating mutation of beta catenin is seen in various colon and stomach adenocarcinomas. SMAD4 mutation is seen in juvenile polyposis, certain colon and pancreatic adenocarcinomas. STK11 mutation is associated with Peutz-Jegher syndrome.

14. A. Irregular glands lined by markedly pleomorphic cells is consistent with adenocarcinoma. When it is limited to mucosa, it is called intramucosal adenocarcinoma. Mucinous adenocarcinoma is characterized by abundant mucin production and less than 50% of the tumor cells are signet ring cells. Sessile serrated adenoma has features of both hyperplastic polyp and adenomatous polyp. Villous adenoma is an adenomatous polyp with more than 75% of villous components. Tubular adenoma has tubular glands lined by columnar cells with elongated hyperchromic nuclei.

15. D. Due to low risk of metastasis, intramucosal adenocarcinoma is treated with polypectomy or mucosal resection. If the margins are not involved by tumor, no additional treatment is needed.

16. A. This patient presents with multiple adenomatous polyp, raising the concern of familial adenomatous polyposis or MUTYH-associated polyposis. Testing for APC and MUTYH would be appropriate to confirm diagnosis. BMPR1A and/or SMAD4 abnormalities are seen in juvenile polyposis, certain colon and pancreatic adenocarcinomas. Microsatellite-instability mutations and CpG methylation are seen in various cancers, including colon cancer, but not familial polyposis. PTEN mutation is seen various tumors, including Cowden syndrome, Breast cancer renal cell carcinoma, endometrioid endometrial adenocarcinoma, etc. STK11 mutation is associated with Peutz-Jegher syndrome. TSC1 and TSC2 mutations are seen in tuberous sclerosis.

17. C. MUTYH-associated polyposis is characterized by multiple adenomatous polyps, but not as many as those seen in familial adenomatous polyposis associated with APC mutation. They tend to have less than 100 polyps started at a later age, while APC mutation is more commonly presents with more than 100 polyps, started from teens, although polyps in both are commonly adenomas. Also see discussion for question 16.

18. D. See discussion of question 9. Inflammatory polyp is characterized by severe acute and chronic inflammation, lack of significant atypia and a history of chronic inflammation such as inflammatory bowel disease.

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