DNB CET Pathology Flashcards

24 sample cards from the Pathology deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. Differentiate emphysema from chronic bronchitis (definition and site).

   Emphysema: permanent enlargement of airspaces distal to terminal bronchiole with alveolar wall destruction (anatomic definition); centriacinar (smoking) or panacinar (alpha-1-antitrypsin deficiency). Chronic bronchitis: clinical—productive cough >3 months in 2 consecutive years; bronchial mucous gland hyperplasia (Reid index).

2. Compare the four stages/phases of lobar pneumonia.

   Congestion (vascular engorgement, bacteria), Red hepatization (RBCs, neutrophils, fibrin fill alveoli; red, firm liver-like), Gray hepatization (RBCs disintegrate, fibrinosuppurative exudate; gray-brown), Resolution (enzymatic digestion, restoration).

3. What are the main histologic types of lung cancer and which is most associated with smoking versus nonsmokers?

   Adenocarcinoma (most common overall, most common in nonsmokers/women, peripheral), Squamous cell carcinoma (central, strong smoking link, hypercalcemia via PTHrP), Small cell carcinoma (central, smoking, paraneoplastic SIADH/Cushing), Large cell carcinoma.

4. What are the histologic features and complications of cirrhosis?

   Cirrhosis = diffuse bridging fibrosis plus regenerative parenchymal nodules disrupting architecture. Complications: portal hypertension (varices, ascites, splenomegaly), hepatic encephalopathy, hepatorenal syndrome, and hepatocellular carcinoma.

5. Differentiate Crohn disease from ulcerative colitis (distribution, depth, key features).

   Crohn: any GI site (mouth to anus), skip lesions, transmural inflammation, non-caseating granulomas, cobblestoning, fistulae, fat-wrapping. UC: colon only, continuous from rectum, mucosal/submucosal inflammation, crypt abscesses, pseudopolyps, no granulomas.

6. What are the gross and microscopic features distinguishing acute tubular necrosis from acute glomerulonephritis on urinalysis?

   ATN: muddy-brown granular casts and renal tubular epithelial cell casts. Acute glomerulonephritis: dysmorphic RBCs and RBC casts with proteinuria. ATN is the most common cause of intrinsic (renal) acute kidney injury.

7. What is the most common renal malignancy in adults and its classic histology and triad?

   Clear cell renal cell carcinoma (originates from proximal tubule epithelium). Clear cytoplasm (glycogen/lipid), associated with VHL gene. Classic triad: flank pain, hematuria, palpable mass (now uncommon).

8. Differentiate the urinary findings of nephrotic versus nephritic syndrome.

   Nephrotic: massive proteinuria (>3.5 g/day), hypoalbuminemia, edema, hyperlipidemia, lipiduria (oval fat bodies, fatty casts). Nephritic: hematuria (RBC casts), mild-moderate proteinuria, hypertension, oliguria, azotemia.

9. What are the histologic hallmarks of Alzheimer disease?

   Neuritic (senile) plaques containing extracellular beta-amyloid (A-beta), neurofibrillary tangles of hyperphosphorylated tau protein, cerebral amyloid angiopathy, and cortical atrophy with hydrocephalus ex vacuo.

10. Differentiate ductal carcinoma in situ from invasive ductal carcinoma of the breast.

    DCIS: malignant epithelial cells confined within the basement membrane of ducts (no invasion), e.g., comedo type with central necrosis. Invasive ductal carcinoma: malignant cells breach the basement membrane into stroma; most common invasive breast cancer, desmoplastic stroma.

11. What are the receptor categories used in breast cancer prognostication and the worst-prognosis subtype?

    ER (estrogen receptor), PR (progesterone receptor), and HER2/neu. Triple-negative (ER-, PR-, HER2-) breast cancer carries the worst prognosis and does not respond to hormonal or HER2-targeted therapy.

12. What virus causes cervical cancer, the high-risk subtypes, and the precursor lesion?

    Human papillomavirus (HPV), high-risk types 16 and 18 (E6 inactivates p53, E7 inactivates RB). Precursor: cervical intraepithelial neoplasia (CIN)/squamous intraepithelial lesion; most cervical cancers are squamous cell carcinoma.

13. Identify these peripheral smear inclusions: Howell-Jolly bodies, Heinz bodies, basophilic stippling, Pappenheimer bodies.

    Howell-Jolly bodies: nuclear (DNA) remnants—post-splenectomy/hyposplenism. Heinz bodies: denatured hemoglobin (G6PD deficiency, seen with supravital stain). Basophilic stippling: aggregated ribosomes—lead poisoning, thalassemia. Pappenheimer bodies: iron granules—sideroblastic anemia.

14. What is a dry tap on bone marrow aspiration and which conditions cause it?

    A dry tap is failure to aspirate marrow. Causes: myelofibrosis, hairy cell leukemia, metastatic infiltration ('packed marrow'), and faulty technique. Trephine biopsy is needed for diagnosis.

15. What are the normal myeloid:erythroid (M:E) ratio in marrow and its interpretation?

    Normal M:E ratio is about 2:1 to 4:1. Increased ratio: myeloid hyperplasia (infection, CML) or erythroid hypoplasia. Decreased ratio: erythroid hyperplasia (hemolysis, blood loss) or myeloid hypoplasia.

16. How is leukemia blast percentage used to diagnose acute leukemia per WHO?

    WHO criterion: >=20% blasts in bone marrow or peripheral blood defines acute leukemia (lowered from the older FAB cutoff of 30%). Certain recurrent cytogenetic abnormalities (e.g., t(15;17)) are diagnostic of AML regardless of blast count.

17. Interpret these urine casts: hyaline, RBC, WBC, granular, waxy, fatty.

    Hyaline: normal/dehydration. RBC: glomerulonephritis. WBC: pyelonephritis/interstitial nephritis. Granular ('muddy brown'): ATN. Waxy/broad: chronic renal failure. Fatty: nephrotic syndrome.

18. What does a positive urine dipstick for nitrites and leukocyte esterase indicate, and what is the significance of glucosuria without hyperglycemia?

    Nitrites + leukocyte esterase indicate urinary tract infection (nitrite implies nitrate-reducing bacteria like E. coli). Glucosuria with normal blood glucose indicates a proximal tubular defect (e.g., Fanconi syndrome) since the renal threshold (~180 mg/dL) is not exceeded.

19. How do CSF findings differentiate bacterial, viral and tubercular meningitis (cells, glucose, protein)?

    Bacterial: neutrophils high, glucose low, protein high, turbid. Viral: lymphocytes, normal glucose, mildly high protein, clear. Tubercular: lymphocytes, low glucose, high protein, cobweb clot formation.

20. Name immunohistochemical markers used to identify: carcinoma (epithelial), sarcoma (mesenchymal), lymphoma, melanoma.

    Epithelial/carcinoma: cytokeratin (CK), EMA. Mesenchymal/sarcoma: vimentin. Lymphoma: CD45 (LCA, leukocyte common antigen); B cells CD20, T cells CD3. Melanoma: S-100, HMB-45, Melan-A.

21. Match these special stains to their target: PAS, Congo red, Prussian blue, Ziehl-Neelsen, Masson trichrome, reticulin.

    PAS: glycogen/basement membrane/fungi. Congo red: amyloid (apple-green birefringence). Prussian blue (Perls): iron/hemosiderin. Ziehl-Neelsen: acid-fast bacilli (TB). Masson trichrome: collagen/fibrosis. Reticulin (silver): reticulin fibers.

22. Which IHC markers are used for prostate (PSA/PSAP), neuroendocrine tumors, and GIST?

    Prostate: PSA and PSAP (prostatic specific acid phosphatase). Neuroendocrine tumors: chromogranin, synaptophysin, CD56, NSE. GIST (gastrointestinal stromal tumor): CD117 (c-KIT) and DOG1.

23. What IHC stain confirms HER2 status and what does a score of 3+ versus 2+ mean in breast cancer?

    HER2/neu IHC: 3+ = positive (strong complete membrane staining in >10% of cells); 0/1+ = negative; 2+ = equivocal, requiring FISH/ISH for HER2 gene amplification confirmation.

24. List the morphologic hallmark of caseous necrosis grossly and microscopically and its key special stain.

    Grossly: friable, cheese-like, yellow-white material. Microscopically: amorphous granular eosinophilic debris within a granuloma surrounded by epithelioid macrophages and Langhans giant cells. Ziehl-Neelsen stain demonstrates acid-fast bacilli.

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