Repeated USMLE Questions Step 1 Review- 139- Pathology

Q- A 65-year-old man presents with progressive shortness of breath and swelling of his legs. Autopsy shows a heart that is firm and rubbery with amyloid deposition between myocardial fibers.
Which of the following best describes the staining characteristics of amyloid?

A- Congo red positive, apple-green birefringence under polarized light

B- Periodic acid-Schiff positive, resistant to diastase

C- Oil Red O positive, indicating lipid material

D- Prussian blue positive, indicating iron deposition

A- Congo red positive, apple-green birefringence under polarized light- Amyloid deposits are confirmed by Congo red stain showing apple-green birefringence. It indicates abnormal fibrillar protein deposition.

 

Q- A 45-year-old woman presents with fatigue and mild hepatosplenomegaly. Peripheral smear reveals teardrop-shaped red cells (dacrocytes) and nucleated RBCs. Bone marrow biopsy is “dry tap.”
What is the most likely diagnosis?

A- Aplastic anemia

B- Myelofibrosis

C- Chronic myeloid leukemia

D- Megaloblastic anemia

B- Myelofibrosis- Bone marrow fibrosis causes extramedullary hematopoiesis and teardrop RBCs. Aspiration yields a “dry tap.”

 

Q- A 23-year-old college student presents with fever, sore throat, and lymphadenopathy. Peripheral smear shows atypical lymphocytes with abundant basophilic cytoplasm.
Which of the following is the most likely causative agent?

A- Cytomegalovirus

B- Adenovirus

C- Epstein-Barr virus

D- Streptococcus pyogenes

C- Epstein-Barr virus- EBV causes infectious mononucleosis with atypical reactive lymphocytes, positive Monospot test, and posterior cervical lymphadenopathy.

 

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