4 clinical MCQs in General Pathology. A study is performed to analyze characteristics of malignant neoplasms in biopsy specimens. Free notes for medical...
Q1. A study is performed to analyze characteristics of malignant neoplasms in biopsy specimens. The biopsies were performed on patients who had palpable mass lesions on digital rectal examination. Of the following microscopic findings, which is most likely to indicate that the neoplasm is malignant?
Answer: Invasion
Explanation: Metastasis would be an even better indicator, but invasion of adjacent tissues suggests malignancy more than the other items listed here. Size increasing beyond 1 cm is also a risk for malignancy in a colonic polypoid lesion. ---
Q2. A 61-year-old man has a screening colonoscopy performed. A 2.7 cm polypoid mass in the rectum is biopsied and diagnosed as grade I on a scale of I to III, and assessed as stage I disease. Which of the following is the best interpretation of these findings in this man?
Answer: Well-differentiated and localized
Explanation: A well-differentiated (low grade) and localized (lower stage) malignant neoplasm often has both a low grade and low stage. In such cases surgery to excise the lesion is more likely to be curative. ---
Q3. A clinical study is performed of oncogenesis in human neoplasms. It is observed that some neoplasms appear to develop from viral oncogenesis, with serologic confirmation of past viral infection. Which of the following neoplasms is most likely to arise in this manner?
Answer: T-cell leukemia
Explanation: Human T-lymphocytotropic virus (HTLV) infection can lead to T-cell leukemia. However, few human cancers arise as a result of viral oncogenesis. Some viruses, such as hepatitis viruses B and C, result in cellular proliferation that increases the risk for subsequent mutations that drive carcinogenesis. ---
Q4. An experiment is designed to study the genetics of cancer. The study will link the appearance of cancer to specific gene abnormalities. Which of the following forms of cell molecular analysis is most useful to identify gene alterations involved in carcinogenesis?
Answer: Single nucleotide polymorphisms
Explanation: SNPs can be analyzed to find alterations present in cancer cells. One could analyze multiple histologically similar cancers to determine what gene(s) alteration(s) such as deletions and amplifications may underlie carcinogenesis. Using millions of SNPs can produce a virtual karyotype down to the gene level. ---