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Pathology Flashcards

7 cards from real NBME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. A 3-year-old child has leukocoria (white pupillary reflex). Retinal biopsy shows small round cells with Flexner-Wintersteiner rosettes. What is the molecular mechanism?

    Answer: Biallelic loss of the RB1 tumor suppressor gene

    Retinoblastoma results from biallelic inactivation of the RB1 gene (chromosome 13q14), which encodes pRb, the key regulator of the G1/S cell-cycle checkpoint.

  2. A 45-year-old man with polycythemia vera develops progressive splenomegaly and marrow fibrosis. Peripheral smear shows tear-drop cells (dacrocytes) and leukoerythroblastosis. What drives the fibrosis?

    Answer: Platelet-derived TGF-beta and PDGF from clonal megakaryocytes

    In myelofibrosis, clonal megakaryocytes release TGF-beta and PDGF that stimulate non-clonal fibroblasts to deposit reticulin and collagen in the marrow.

  3. A 62-year-old woman has a lung nodule with positive PD-L1 staining (>50%) and no EGFR/ALK alterations. What histologic type is this most likely?

    Answer: Adenocarcinoma

    Adenocarcinoma is the most common non-small cell lung cancer, most likely to be PD-L1 high and targetable with pembrolizumab as first-line when EGFR/ALK negative.

  4. A 55-year-old man has massive hematemesis. Endoscopy shows a bleeding vessel in a gastric ulcer in the posterior wall of the duodenum. Which artery is most likely eroded?

    Answer: Gastroduodenal artery

    Posterior duodenal ulcers can erode the gastroduodenal artery, which runs behind the first part of the duodenum, causing life-threatening hemorrhage.

  5. A 38-year-old woman has hypertension, hypokalemia, and suppressed plasma renin. CT shows a 1.5 cm left adrenal adenoma. What does the tumor cell secrete in excess?

    Answer: Aldosterone

    Primary hyperaldosteronism (Conn syndrome) due to adrenocortical adenoma causes excess aldosterone secretion, leading to sodium retention, hypertension, and hypokalemia with suppressed renin.

  6. A 25-year-old man with Marfan syndrome ruptures his aorta. Histology shows fragmentation of elastic fibers and increased ground substance in the media. What is this finding called?

    Answer: Cystic medial necrosis (medionecrosis)

    Cystic medial necrosis describes degeneration of elastic tissue and smooth muscle in the aortic media with mucoid material accumulation, seen in Marfan syndrome and hypertension.

  7. A 48-year-old man presents with jaundice and a palpable, non-tender gallbladder. CT shows a mass in the head of the pancreas. What embryologic structure gives rise to most pancreatic ductal adenocarcinomas?

    Answer: Pancreatic ductal epithelium derived from foregut endoderm

    Pancreatic ductal adenocarcinoma arises from ductal epithelium of foregut endoderm origin and commonly obstructs the common bile duct when in the head of the pancreas.