USMLE STEP 3 2026 COMPREHENSIVE SET
SOLVED QUESTIONS AND SOLUTIONS
◉Myelofibrosis. Answer: Obliteration of the bone marrow with
fibrosis
Megakaryocytes produce PDGF → fibrosis
Presentation:
1. Splenomegaly
2. Teardrop RBCs
Lab findings
↓ RBCs
variable WBCs
variable platelets
30-50% JAK2 mutation
◉Teardrop RBCs are associated with which disease?. Answer:
myelofibrosis
,◉Myelodysplastic syndrome. Answer: Stem cell disorder involved in
ineffective hematopoiesis resulting in defects in cell maturation of
nonlymphoid lineages
Lab Findings:
Hypercellular bone marrow
Peripheral cytopenia
Pseudo-Pelger-Huet Anomaly- neutrophils with bilobed nuclei
Causes:
De novo mutations
Radiation
Benzene exposure
Chemotherapy
↑ Risk of transformation to AML
◉Pseudo-Pelger-Heut Anomaly is associated with which disease?.
Answer: Myelodysplastic syndromes
Neutrophils with bilobed nuclei (heut duet)
, ◉Aplastic Anemia. Answer: Caused by failure or destruction of
myeloid stem cells 2/2:
- Radiation
- Drugs: benzene, chloramphenicol, alkylating agents,
antimetabolites
- Viruses: EBV, HIV, Hepatitis
- Fanconi anemia
- Idiopathic
Lab findings:
↓ Reticulocyte count
↑ EPO
Pancytopenia
Hypocellular bone marrow
Treatment:
Immunosuppression- anti-thymocyte globulin, cyclosporine
Bone marrow allograft
Transfusion
Bone marrow stimulation with GM-CSF
SOLVED QUESTIONS AND SOLUTIONS
◉Myelofibrosis. Answer: Obliteration of the bone marrow with
fibrosis
Megakaryocytes produce PDGF → fibrosis
Presentation:
1. Splenomegaly
2. Teardrop RBCs
Lab findings
↓ RBCs
variable WBCs
variable platelets
30-50% JAK2 mutation
◉Teardrop RBCs are associated with which disease?. Answer:
myelofibrosis
,◉Myelodysplastic syndrome. Answer: Stem cell disorder involved in
ineffective hematopoiesis resulting in defects in cell maturation of
nonlymphoid lineages
Lab Findings:
Hypercellular bone marrow
Peripheral cytopenia
Pseudo-Pelger-Huet Anomaly- neutrophils with bilobed nuclei
Causes:
De novo mutations
Radiation
Benzene exposure
Chemotherapy
↑ Risk of transformation to AML
◉Pseudo-Pelger-Heut Anomaly is associated with which disease?.
Answer: Myelodysplastic syndromes
Neutrophils with bilobed nuclei (heut duet)
, ◉Aplastic Anemia. Answer: Caused by failure or destruction of
myeloid stem cells 2/2:
- Radiation
- Drugs: benzene, chloramphenicol, alkylating agents,
antimetabolites
- Viruses: EBV, HIV, Hepatitis
- Fanconi anemia
- Idiopathic
Lab findings:
↓ Reticulocyte count
↑ EPO
Pancytopenia
Hypocellular bone marrow
Treatment:
Immunosuppression- anti-thymocyte globulin, cyclosporine
Bone marrow allograft
Transfusion
Bone marrow stimulation with GM-CSF
