General Pathology Practice Questions

Q: Which of the following conditions is not primarily caused by a genetic mutation?

Diabetes mellitus type II. The core concept tested here is the distinction between **monogenic (Mendelian) disorders** and **multifactorial (polygenic) diseases**. [1] **Why Diabetes Mellitus Type II (DM-II) is the correct answer:** DM-II is a **multifactorial disease**. While it has a strong genetic predisposition (often stronger than Type I), it is not caused by a single primary mutation. Instead, it results from a complex interplay between **polygenic susceptibility** (multiple gene variants) and **environmental triggers** such as obesity, sedentary lifestyle, and aging. [1] It does not follow a classic Mendelian inheritance pattern. **Why the other options are incorrect:** * **Cystic Fibrosis:** A classic **Autosomal Recessive** disorder caused by mutations in the *CFTR* gene on chromosome 7. [2] * **Hemophilia:** An **X-linked Recessive** bleeding disorder caused by mutations in genes encoding Factor VIII (Hemophilia A) or Factor IX (Hemophilia B). * **Alpha-1 Antitrypsin Deficiency:** An **Autosomal Codominant** disorder caused by mutations in the *SERPINA1* gene, leading to emphysema and liver cirrhosis. **NEET-PG High-Yield Pearls:** * **Strongest Genetic Link:** Between DM-I and DM-II, **DM-II** has a higher concordance rate in monozygotic twins (up to 90%). * **MODY (Maturity Onset Diabetes of the Young):** Unlike DM-II, MODY is **monogenic** (Autosomal Dominant). The most common type is **MODY 3** (*HNF1-alpha* mutation). * **Polygenic vs. Monogenic:** Most common chronic diseases (HTN, DM-II, CAD) are polygenic, whereas rare "textbook" diseases are usually monogenic. [1]

Q: Cystic fibrosis affects all systems EXCEPT:

Endocrine. **Explanation:** Cystic Fibrosis (CF) is an autosomal recessive disorder caused by mutations in the **CFTR gene**, which encodes a chloride channel [1]. This defect leads to the production of thick, viscid secretions in **exocrine glands**. **Why "Endocrine" is the correct answer:** The primary pathology of CF involves **exocrine dysfunction**. While CF frequently leads to "Cystic Fibrosis-Related Diabetes" (CFRD), this occurs because the thick secretions obstruct the pancreatic ducts, leading to secondary scarring and destruction of the islet cells (an **exocrine-driven** destruction of endocrine tissue). The endocrine system as a whole (pituitary, thyroid, adrenal) is not primarily affected by CFTR mutations. **Analysis of Incorrect Options:** * **Respiratory:** This is the most common cause of morbidity [2]. Thick mucus leads to bronchiectasis, recurrent infections (notably *Pseudomonas*), and nasal polyps [1]. * **Hepatobiliary:** Obstruction of bile ductules leads to focal biliary cirrhosis, neonatal cholestasis, and gallstones. * **Genitourinary:** Over 95% of males are infertile due to **Congenital Bilateral Absence of the Vas Deferens (CBAVD)** [1]. In females, thick cervical mucus can reduce fertility. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Sweat Chloride Test (>60 mEq/L). * **Most Common Mutation:** ΔF508 (Class II mutation - protein misfolding). * **Pancreatic Status:** 85-90% of patients have pancreatic exocrine insufficiency (malabsorption/steat同年rhea). * **GI Complication:** Meconium ileus is a classic presenting sign in neonates. * **Microbiology:** *Staphylococcus aureus* is common in early childhood; *Pseudomonas aeruginosa* is the dominant pathogen in adults.

Q: Which intermediate filament is characteristic of fibroblasts?

Vimentin. **Explanation:** Intermediate filaments (IFs) are crucial components of the cytoskeleton that provide mechanical strength to cells. They are highly tissue-specific, making them excellent immunohistochemical (IHC) markers in diagnostic pathology. **Why Vimentin is correct:** **Vimentin** is the characteristic intermediate filament of **mesenchymal cells**. Since fibroblasts are the prototypical cells of mesenchymal origin (connective tissue), they express vimentin. In tumor pathology, Vimentin is used as a primary marker for **sarcomas** (malignancies of mesenchymal origin). **Analysis of Incorrect Options:** * **Lamin A:** These are nuclear intermediate filaments found in the **nuclear lamina** (inner lining of the nuclear envelope) of most differentiated somatic cells, not specific to the cytoplasmic cytoskeleton of fibroblasts. * **Desmin:** This is the marker for **muscle cells** (skeletal, cardiac, and smooth muscle). It is used clinically to identify tumors like rhabdomyosarcomas or leiomyosarcomas. * **Cytokeratin:** This is the characteristic marker for **epithelial cells**. It is the primary IHC marker used to diagnose **carcinomas**. **NEET-PG High-Yield Pearls:** * **Vimentin** is also positive in Melanoma, Renal Cell Carcinoma (RCC), and Endometrial Carcinoma (exceptions where epithelial tumors show vimentin). * **Glial Fibrillary Acidic Protein (GFAP):** Marker for astrocytes and ependymal cells (Glial tumors/Gliomas). * **Neurofilaments:** Marker for neurons and neural tumors (e.g., Neuroblastoma). * **Synaptophysin/Chromogranin:** Markers for neuroendocrine tumors.

Question 1

All endothelial cells produce thrombomodulin except those found in which of the following circulations?

Accepted Answer

Cerebral microcirculation

Answer

Hepatic circulation

Answer

Cutaneous circulation

Answer

Renal circulation

Question 2

Which of the following conditions is not primarily caused by a genetic mutation?

Accepted Answer

Diabetes mellitus type II

Answer

Cystic fibrosis

Answer

Hemophilia

Answer

Alpha 1 antitrypsin deficiency

Question 3

Which of the following is not typically seen in cystic fibrosis?

Accepted Answer

Limb anomalies

Answer

Meconium ileus

Answer

Female infertility

Answer

Lung infection

Question 4

Cystic fibrosis affects all systems EXCEPT:

Accepted Answer

Endocrine

Answer

Respiratory

Answer

Hepatobiliary

Answer

Genitourinary

Question 5

On sectioning of an organ at autopsy, a focal, wedge-shaped firm area is seen accompanied by extensive hemorrhage and a red appearance. The lesion has a base on the surface of the organ. This finding is typically of:

Accepted Answer

Lung with pulmonary thromboembolism

Answer

Liver with hypovolemic shock

Answer

Heart with coronary thrombosis

Answer

Kidney with septic embolus

Question 6

Edema is caused by all of the following mechanisms, EXCEPT:

Accepted Answer

Increased plasma proteins

Answer

Increased vascular permeability

Answer

Obstruction to lymphatic flow

Answer

Sodium retention

Question 7

Which intermediate filament is characteristic of fibroblasts?

Accepted Answer

Vimentin

Answer

Lamin A

Answer

Desmin

Answer

Cytokeratin

Question 8

In hemodialysis-associated amyloidosis, which of the following is seen?

Accepted Answer

beta-2 microglobulin

Answer

Transthyretin

Answer

SAA

Answer

alpha-1 microglobulin

Question 9

Which of the following is NOT an example of metaplasia?

Accepted Answer

Breast enlargement at puberty

Answer

Barrett's esophagus

Answer

Myositis ossificans

Answer

Respiratory tract epithelium in chronic smokers

Question 10

Foam cells are characteristically seen in which of the following conditions?

Accepted Answer

Niemann-Pick disease

Answer

Alpo syndrome

Answer

Atherosclerosis

Answer

Pneumonia

General Pathology — MCQs

General Pathology — MCQs

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