NBME 25 COMPREHENSIVE BASIC SCIENCE SELF-ASSESSMENT
REAL QUESTIONS + DETAILED ANSWERS - LATEST VERSION -
TOP RATED 2026/2027 (PASS GUARANTEE)
1. A 45-year-old man presents with progressive weakness of his proximal
muscles. Laboratory studies show elevated creatine kinase. Muscle biopsy
reveals inflammatory infiltrate surrounding but not invading muscle fibers.
Which of the following is the most likely diagnosis?
A. Dermatomyositis
B. Duchenne muscular dystrophy
C. Lambert-Eaton syndrome
D. Myasthenia gravis
E. Polymyositis
2. A 62-year-old woman with a history of breast cancer presents with
confusion, constipation, and polyuria. Laboratory studies reveal a serum
calcium of 13.2 mg/dL. Which of the following is the most likely cause of her
hypercalcemia?
A. Ectopic PTH production
B. Excess vitamin D intake
C. Increased osteoblastic activity
D. PTHrP secretion by the tumor
E. Primary hyperparathyroidism
3. A newborn is found to have ambiguous genitalia. Karyotype is 46,XX.
Laboratory studies show markedly elevated 17-hydroxyprogesterone. Which
of the following enzyme deficiencies is most likely responsible?
A. 11-beta-hydroxylase
B. 17-alpha-hydroxylase
, C. 21-hydroxylase
D. 3-beta-hydroxysteroid dehydrogenase
E. Aromatase
4. A 28-year-old man presents with fever, night sweats, and cervical
lymphadenopathy. Biopsy of the lymph node shows large binucleate cells
with prominent 'owl eye' nucleoli. Which of the following cell types are these
malignant cells derived from?
A. B lymphocytes
B. Dendritic cells
C. Macrophages
D. Natural killer cells
E. T lymphocytes
5. A 55-year-old man with a long-standing history of GERD presents with
dysphagia. Endoscopy reveals replacement of normal squamous epithelium
of the lower esophagus with columnar epithelium. This condition increases
the risk of which of the following?
A. Adenocarcinoma
B. Leiomyoma
C. Leiomyosarcoma
D. Squamous cell carcinoma
E. Small cell carcinoma
6. A 70-year-old man develops sudden onset of crushing chest pain radiating
to the left arm. ECG shows ST elevation in leads II, III, and aVF. Which
coronary artery is most likely occluded?
A. Left anterior descending artery
B. Left circumflex artery
C. Left main coronary artery
D. Right coronary artery
E. Right marginal artery
7. A 35-year-old woman presents with amenorrhea and galactorrhea. MRI
reveals a pituitary adenoma. Elevated levels of which hormone are most
directly responsible for her amenorrhea?
, A. Estradiol
B. Follicle-stimulating hormone
C. Growth hormone
D. Luteinizing hormone
E. Prolactin
8. A 5-year-old boy presents with recurrent sinopulmonary infections since
infancy. Laboratory studies show absent B cells and very low
immunoglobulin levels. T cell counts are normal. Which of the following is
the most likely diagnosis?
A. Bruton agammaglobulinemia
B. Common variable immunodeficiency
C. DiGeorge syndrome
D. Severe combined immunodeficiency
E. Wiskott-Aldrich syndrome
9. A 40-year-old woman presents with watery diarrhea, flushing, and
wheezing. Urine 5-HIAA is markedly elevated. CT scan shows a mass in the
terminal ileum with liver metastases. Which of the following mediators is
most responsible for her symptoms?
A. Gastrin
B. Glucagon
C. Histamine
D. Serotonin
E. Vasoactive intestinal peptide
10. A 60-year-old man with a 40-pack-year smoking history presents with
hemoptysis and weight loss. Chest X-ray reveals a hilar mass. Biopsy shows
small dark cells with scant cytoplasm arranged in clusters. Which of the
following paraneoplastic syndromes is most commonly associated with this
tumor?
A. Cushing syndrome due to ectopic ACTH
B. Hypercalcemia due to PTHrP
C. Hypertrophic osteoarthropathy
D. Migratory thrombophlebitis
E. Syndrome of inappropriate ADH
, 11. A 25-year-old woman presents with episodes of palpitations, diaphoresis,
and severe headache. Blood pressure during an episode is 220/120 mmHg.
24-hour urine shows elevated catecholamines. Which of the following is the
most likely diagnosis?
A. Carcinoid tumor
B. Conn syndrome
C. Cushing disease
D. Pheochromocytoma
E. Renal artery stenosis
12. A 3-year-old child presents with failure to thrive, fatty stools, and
recurrent pulmonary infections. Sweat chloride test is markedly elevated.
Which of the following genetic mutations is most commonly responsible?
A. Deletion of phenylalanine at position 508
B. Frameshift mutation in dystrophin gene
C. Missense mutation in beta-globin gene
D. Nonsense mutation in APC gene
E. Trinucleotide repeat expansion in FMR1
13. A 50-year-old man presents with a lytic bone lesion, hypercalcemia, and
renal insufficiency. Serum protein electrophoresis shows a monoclonal spike.
Bone marrow biopsy reveals plasma cells comprising 30% of the marrow.
Which of the following is most likely elevated in the urine?
A. Albumin
B. Beta-2 microglobulin only
C. Bence Jones proteins (free light chains)
D. IgG heavy chains
E. Transferrin
14. A 22-year-old woman presents with joint pain, malar rash, and
photosensitivity. Laboratory studies show positive ANA, anti-dsDNA
antibodies, and hypocomplementemia. Urinalysis reveals red cell casts.
Which complement pathway is primarily involved in the pathogenesis?
A. Alternative pathway
B. Classical pathway
C. Lectin binding pathway
REAL QUESTIONS + DETAILED ANSWERS - LATEST VERSION -
TOP RATED 2026/2027 (PASS GUARANTEE)
1. A 45-year-old man presents with progressive weakness of his proximal
muscles. Laboratory studies show elevated creatine kinase. Muscle biopsy
reveals inflammatory infiltrate surrounding but not invading muscle fibers.
Which of the following is the most likely diagnosis?
A. Dermatomyositis
B. Duchenne muscular dystrophy
C. Lambert-Eaton syndrome
D. Myasthenia gravis
E. Polymyositis
2. A 62-year-old woman with a history of breast cancer presents with
confusion, constipation, and polyuria. Laboratory studies reveal a serum
calcium of 13.2 mg/dL. Which of the following is the most likely cause of her
hypercalcemia?
A. Ectopic PTH production
B. Excess vitamin D intake
C. Increased osteoblastic activity
D. PTHrP secretion by the tumor
E. Primary hyperparathyroidism
3. A newborn is found to have ambiguous genitalia. Karyotype is 46,XX.
Laboratory studies show markedly elevated 17-hydroxyprogesterone. Which
of the following enzyme deficiencies is most likely responsible?
A. 11-beta-hydroxylase
B. 17-alpha-hydroxylase
, C. 21-hydroxylase
D. 3-beta-hydroxysteroid dehydrogenase
E. Aromatase
4. A 28-year-old man presents with fever, night sweats, and cervical
lymphadenopathy. Biopsy of the lymph node shows large binucleate cells
with prominent 'owl eye' nucleoli. Which of the following cell types are these
malignant cells derived from?
A. B lymphocytes
B. Dendritic cells
C. Macrophages
D. Natural killer cells
E. T lymphocytes
5. A 55-year-old man with a long-standing history of GERD presents with
dysphagia. Endoscopy reveals replacement of normal squamous epithelium
of the lower esophagus with columnar epithelium. This condition increases
the risk of which of the following?
A. Adenocarcinoma
B. Leiomyoma
C. Leiomyosarcoma
D. Squamous cell carcinoma
E. Small cell carcinoma
6. A 70-year-old man develops sudden onset of crushing chest pain radiating
to the left arm. ECG shows ST elevation in leads II, III, and aVF. Which
coronary artery is most likely occluded?
A. Left anterior descending artery
B. Left circumflex artery
C. Left main coronary artery
D. Right coronary artery
E. Right marginal artery
7. A 35-year-old woman presents with amenorrhea and galactorrhea. MRI
reveals a pituitary adenoma. Elevated levels of which hormone are most
directly responsible for her amenorrhea?
, A. Estradiol
B. Follicle-stimulating hormone
C. Growth hormone
D. Luteinizing hormone
E. Prolactin
8. A 5-year-old boy presents with recurrent sinopulmonary infections since
infancy. Laboratory studies show absent B cells and very low
immunoglobulin levels. T cell counts are normal. Which of the following is
the most likely diagnosis?
A. Bruton agammaglobulinemia
B. Common variable immunodeficiency
C. DiGeorge syndrome
D. Severe combined immunodeficiency
E. Wiskott-Aldrich syndrome
9. A 40-year-old woman presents with watery diarrhea, flushing, and
wheezing. Urine 5-HIAA is markedly elevated. CT scan shows a mass in the
terminal ileum with liver metastases. Which of the following mediators is
most responsible for her symptoms?
A. Gastrin
B. Glucagon
C. Histamine
D. Serotonin
E. Vasoactive intestinal peptide
10. A 60-year-old man with a 40-pack-year smoking history presents with
hemoptysis and weight loss. Chest X-ray reveals a hilar mass. Biopsy shows
small dark cells with scant cytoplasm arranged in clusters. Which of the
following paraneoplastic syndromes is most commonly associated with this
tumor?
A. Cushing syndrome due to ectopic ACTH
B. Hypercalcemia due to PTHrP
C. Hypertrophic osteoarthropathy
D. Migratory thrombophlebitis
E. Syndrome of inappropriate ADH
, 11. A 25-year-old woman presents with episodes of palpitations, diaphoresis,
and severe headache. Blood pressure during an episode is 220/120 mmHg.
24-hour urine shows elevated catecholamines. Which of the following is the
most likely diagnosis?
A. Carcinoid tumor
B. Conn syndrome
C. Cushing disease
D. Pheochromocytoma
E. Renal artery stenosis
12. A 3-year-old child presents with failure to thrive, fatty stools, and
recurrent pulmonary infections. Sweat chloride test is markedly elevated.
Which of the following genetic mutations is most commonly responsible?
A. Deletion of phenylalanine at position 508
B. Frameshift mutation in dystrophin gene
C. Missense mutation in beta-globin gene
D. Nonsense mutation in APC gene
E. Trinucleotide repeat expansion in FMR1
13. A 50-year-old man presents with a lytic bone lesion, hypercalcemia, and
renal insufficiency. Serum protein electrophoresis shows a monoclonal spike.
Bone marrow biopsy reveals plasma cells comprising 30% of the marrow.
Which of the following is most likely elevated in the urine?
A. Albumin
B. Beta-2 microglobulin only
C. Bence Jones proteins (free light chains)
D. IgG heavy chains
E. Transferrin
14. A 22-year-old woman presents with joint pain, malar rash, and
photosensitivity. Laboratory studies show positive ANA, anti-dsDNA
antibodies, and hypocomplementemia. Urinalysis reveals red cell casts.
Which complement pathway is primarily involved in the pathogenesis?
A. Alternative pathway
B. Classical pathway
C. Lectin binding pathway
