NBME CBSE (USMLE STEP 1) 2026-2027: THE GOLD
STANDARD TEST BANK 180 High-Yield Clinical Vignettes
with Integrated Basic Science | Derived from NBME
Comprehensive Basic Science Examination Content
Outline | Guaranteed First-Time Pass
Q1. A 52-year-old male with a 30-pack-year smoking history presents with a
persistent cough, hemoptysis, and a 15-pound weight loss over the past 3
months. A chest CT reveals a 4 cm mass in the right main bronchus with
mediastinal lymphadenopathy. Biopsy shows malignant cells with
abundant cytoplasm and central nuclei, forming a "pagetoid" pattern.
Which of the following tumor markers is MOST likely elevated in this
patient's serum?
A) Alpha-fetoprotein
B) Beta-human chorionic gonadotropin
C) Carcinoembryonic antigen
D) Neuron-specific enolase
E) Squamous cell carcinoma antigen
Correct Answer: C
Rationale: This patient has small cell lung carcinoma (SCLC) , characterized
by the "pagetoid" pattern, abundant cytoplasm, and central nuclei.
,Carcinoembryonic antigen (CEA)is frequently elevated in SCLC and other
lung cancers. Alpha-fetoprotein is associated with hepatocellular carcinoma
and germ cell tumors. Beta-hCG is associated with gestational trophoblastic
disease and germ cell tumors. NSE is also elevated in SCLC but CEA is the
classic marker. Squamous cell carcinoma antigen is associated with
squamous cell carcinoma of the lung and cervix.
Q2. A 65-year-old female presents with a 3-month history of progressive
fatigue, weight loss, and abdominal pain. Physical examination reveals
hepatomegaly and ascites. Laboratory studies show elevated serum
alkaline phosphatase and alpha-fetoprotein. A liver biopsy reveals
malignant cells forming glandular structures. Which of the following is the
MOST common risk factor for this malignancy?
A) Hepatitis B virus infection
B) Hepatitis C virus infection
C) Alcohol use disorder
D) Nonalcoholic fatty liver disease
E) Aflatoxin exposure
Correct Answer: A
Rationale: This patient has hepatocellular carcinoma (HCC) , characterized
by elevated AFP and malignant cells forming glandular structures
,(trabecular pattern). Hepatitis B virus (HBV) infection is the most common
risk factor for HCC worldwide, particularly in endemic regions. Hepatitis C
virus infection, alcohol use disorder, NAFLD, and aflatoxin exposure are
also risk factors but are less common globally. HBV integrates into the host
genome and produces the HBx protein, which promotes hepatocellular
carcinogenesis.
Q3. A 58-year-old male with a history of chronic pancreatitis presents with
jaundice, dark urine, and light-colored stools. Laboratory studies show
elevated serum bilirubin, alkaline phosphatase, and CA 19-9. A CT scan
reveals a mass in the head of the pancreas. Which of the following is the
MOST common genetic mutation associated with this malignancy?
A) KRAS mutation
B) TP53 mutation
C) SMAD4 mutation
D) BRCA2 mutation
E) CDKN2A mutation
Correct Answer: A
Rationale: This patient has pancreatic ductal adenocarcinoma ,
characterized by an obstructive jaundice presentation and elevated CA 19-
9. KRAS mutations*are the most common genetic alterations in pancreatic
, cancer, occurring in over 90% of cases. TP53 mutations (50-70%), SMAD4
mutations (50%), BRCA2 mutations (10-15%), and CDKN2A mutations (10-
20%) are also seen but are less common. KRAS mutations occur early in
pancreatic carcinogenesis, making them a hallmark of this malignancy.
**Q4.** A 72-year-old male presents with a 6-month history of progressive
dysphagia, first with solids and now with liquids. He reports a 25-pound
weight loss over the past 4 months. An upper endoscopy reveals a mass in
the distal esophagus with an ulcerated appearance. Biopsy shows
malignant cells with glandular formation. Which of the following is the
MOST likely precursor lesion for this malignancy?
A) Barrett esophagus
B) Squamous dysplasia
C) Adenomatous polyps
D) Hyperplastic polyps
E) Gastrointestinal stromal tumor
Correct Answer: A
Rationale: This patient has esophageal adenocarcinoma , which arises from
**Barrett esophagus (intestinal metaplasia of the esophageal mucosa).
Barrett esophagus results from chronic GERD, leading to metaplastic
STANDARD TEST BANK 180 High-Yield Clinical Vignettes
with Integrated Basic Science | Derived from NBME
Comprehensive Basic Science Examination Content
Outline | Guaranteed First-Time Pass
Q1. A 52-year-old male with a 30-pack-year smoking history presents with a
persistent cough, hemoptysis, and a 15-pound weight loss over the past 3
months. A chest CT reveals a 4 cm mass in the right main bronchus with
mediastinal lymphadenopathy. Biopsy shows malignant cells with
abundant cytoplasm and central nuclei, forming a "pagetoid" pattern.
Which of the following tumor markers is MOST likely elevated in this
patient's serum?
A) Alpha-fetoprotein
B) Beta-human chorionic gonadotropin
C) Carcinoembryonic antigen
D) Neuron-specific enolase
E) Squamous cell carcinoma antigen
Correct Answer: C
Rationale: This patient has small cell lung carcinoma (SCLC) , characterized
by the "pagetoid" pattern, abundant cytoplasm, and central nuclei.
,Carcinoembryonic antigen (CEA)is frequently elevated in SCLC and other
lung cancers. Alpha-fetoprotein is associated with hepatocellular carcinoma
and germ cell tumors. Beta-hCG is associated with gestational trophoblastic
disease and germ cell tumors. NSE is also elevated in SCLC but CEA is the
classic marker. Squamous cell carcinoma antigen is associated with
squamous cell carcinoma of the lung and cervix.
Q2. A 65-year-old female presents with a 3-month history of progressive
fatigue, weight loss, and abdominal pain. Physical examination reveals
hepatomegaly and ascites. Laboratory studies show elevated serum
alkaline phosphatase and alpha-fetoprotein. A liver biopsy reveals
malignant cells forming glandular structures. Which of the following is the
MOST common risk factor for this malignancy?
A) Hepatitis B virus infection
B) Hepatitis C virus infection
C) Alcohol use disorder
D) Nonalcoholic fatty liver disease
E) Aflatoxin exposure
Correct Answer: A
Rationale: This patient has hepatocellular carcinoma (HCC) , characterized
by elevated AFP and malignant cells forming glandular structures
,(trabecular pattern). Hepatitis B virus (HBV) infection is the most common
risk factor for HCC worldwide, particularly in endemic regions. Hepatitis C
virus infection, alcohol use disorder, NAFLD, and aflatoxin exposure are
also risk factors but are less common globally. HBV integrates into the host
genome and produces the HBx protein, which promotes hepatocellular
carcinogenesis.
Q3. A 58-year-old male with a history of chronic pancreatitis presents with
jaundice, dark urine, and light-colored stools. Laboratory studies show
elevated serum bilirubin, alkaline phosphatase, and CA 19-9. A CT scan
reveals a mass in the head of the pancreas. Which of the following is the
MOST common genetic mutation associated with this malignancy?
A) KRAS mutation
B) TP53 mutation
C) SMAD4 mutation
D) BRCA2 mutation
E) CDKN2A mutation
Correct Answer: A
Rationale: This patient has pancreatic ductal adenocarcinoma ,
characterized by an obstructive jaundice presentation and elevated CA 19-
9. KRAS mutations*are the most common genetic alterations in pancreatic
, cancer, occurring in over 90% of cases. TP53 mutations (50-70%), SMAD4
mutations (50%), BRCA2 mutations (10-15%), and CDKN2A mutations (10-
20%) are also seen but are less common. KRAS mutations occur early in
pancreatic carcinogenesis, making them a hallmark of this malignancy.
**Q4.** A 72-year-old male presents with a 6-month history of progressive
dysphagia, first with solids and now with liquids. He reports a 25-pound
weight loss over the past 4 months. An upper endoscopy reveals a mass in
the distal esophagus with an ulcerated appearance. Biopsy shows
malignant cells with glandular formation. Which of the following is the
MOST likely precursor lesion for this malignancy?
A) Barrett esophagus
B) Squamous dysplasia
C) Adenomatous polyps
D) Hyperplastic polyps
E) Gastrointestinal stromal tumor
Correct Answer: A
Rationale: This patient has esophageal adenocarcinoma , which arises from
**Barrett esophagus (intestinal metaplasia of the esophageal mucosa).
Barrett esophagus results from chronic GERD, leading to metaplastic
