General Pathology — MCQs

A 62-year-old man with a 20-year history of poorly controlled type 2 diabetes mellitus undergoes renal biopsy for progressive proteinuria and declining GFR. The photomicrograph shows glomeruli with periodic acid-Schiff (PAS)-positive, homogeneous, ovoid deposits in the mesangium that compress the glomerular capillaries; the deposits are acellular and do not stain with Congo red. Electron microscopy shows increased mesangial matrix without electron-dense deposits. Which of the following mechanisms is most directly responsible for the formation of the lesions seen in this biopsy?

A 58-year-old man with a 40-pack-year smoking history presents with progressive dyspnea and a dry cough. Chest CT reveals bilateral lower lobe interstitial infiltrates. Bronchoalveolar lavage is performed. Prussian blue staining of the lavage material reveals elongated structures with a beaded, golden-brown coating. Which of the following is the most likely mechanism by which these structures form?

A 35-year-old woman with no significant past medical, past surgical, family or social history presents to clinic with a recently identified area of flat, intact, pigmented skin. The patient believes that this is a large freckle, and she states that it becomes darker during the summer when she is outdoors. On physical examination, you measure the lesion to be 6 mm in diameter. Which of the following is the best descriptor of this patient’s skin finding?

A 68-year-old male is brought to his primary care physician by his wife who is concerned that the patient seems more confused and irritable than usual. Three months ago, she started noticing that he appeared confused while doing simple tasks and seemed to be off balance. He has fallen several times over that time period. She has also noticed that if he is startled by one of their grandchildren, his arm starts to twitch uncontrollably. His past medical history is notable for transient ischemic attacks, hypertension, and hyperlipidemia. He takes aspirin, enalapril, hydrochlorothiazide, and rosuvastatin. He has a 30 pack-year smoking history. His family history is notable for Alzheimer’s disease in his mother and maternal uncle. His temperature is 98.6°F (37°C), blood pressure is 130/70 mmHg, pulse is 95/min, and respirations are 16/min. Physical examination reveals dysmetria and an ataxic gait. This patient’s condition is most strongly associated with which of the following findings on brain autopsy?

A 21-year-old man comes to the physician because of painful, firm, dark bumps on his neck and jawline. He has no history of serious illness and takes no medications. His brother had a similar rash. A photograph of the rash is shown. Which of the following is the most likely underlying mechanism of this patient's condition?