Weekly Pathology Exam - March 7, 2026 (Section A: MCQs) | MCQ Quiz | OmpathStudy Kenya

Question 1

A 45-year-old woman undergoes imaging for unrelated abdominal pain, revealing a 3 cm incidental liver lesion. Given its suspected diagnosis as the most common benign liver tumor, which of the following diagnostic procedures should be avoided?

Accepted Answer

Percutaneous needle biopsy — The most common benign liver tumor is a cavernous hemangioma. Percutaneous biopsy is avoided due to the significant risk of hemorrhage from the vascular channels.

Question 2

A 28-year-old woman on oral contraceptive pills presents with sudden onset severe RUQ pain and hypovolemic shock. Imaging reveals a ruptured hepatic mass. Which tumor is most likely?

Accepted Answer

Hepatic Adenoma — Hepatic adenomas are strongly associated with oral contraceptive use and have a high risk of rupture and intraperitoneal hemorrhage, especially during pregnancy or menstruation.

Question 3

A liver lesion in a 35-year-old male shows a central stellate scar and radiating fibrous septa containing anomalous arteries and bile ductules. What is the diagnosis?

Accepted Answer

Focal Nodular Hyperplasia — Focal Nodular Hyperplasia (FNH) is characterized by a central stellate scar and is thought to be a hyperplastic response to a pre-existing vascular malformation.

Question 4

Which of the following risk factors is most strongly associated with the development of Hepatocellular Carcinoma (HCC) globally?

Accepted Answer

Chronic Hepatitis B Infection — Globally, chronic Hepatitis B virus infection is the most common risk factor for HCC, particularly in high-prevalence areas like Asia and sub-Saharan Africa.

Question 5

A 62-year-old male with chronic Hep C and cirrhosis has a liver mass. Which tumor marker, if significantly elevated ( 1000 ng/ml), is highly suggestive of HCC?

Accepted Answer

Alpha-fetoprotein (AFP) — AFP is the primary serum marker for HCC; levels 1000 ng/ml are highly specific for the diagnosis in the context of a liver mass.

Question 6

A 70-year-old man with PSC develops jaundice and an intrahepatic mass. His AFP is normal. Which primary liver malignancy is most consistent with this?

Accepted Answer

Cholangiocarcinoma — Primary Sclerosing Cholangitis (PSC) is a major risk factor for cholangiocarcinoma. High AFP is usually associated with HCC, not cholangiocarcinoma.

Question 7

A 58-year-old female presents with multiple bilateral liver lesions and no history of liver disease. What is the most common diagnosis?

Accepted Answer

Metastatic adenocarcinoma — Metastatic disease is the most common malignancy of the liver in adults, most frequently originating from the colon, breast, or lung.

Question 8

A 2-year-old child presents with a RUQ mass. Biopsy reveals a malignant epithelial tumor with primitive mesenchymal stroma. What is the diagnosis?

Accepted Answer

Hepatoblastoma — Hepatoblastoma is the most common primary liver tumor in childhood, typically occurring before age 3.

Question 9

Exposure to which of the following substances is a significant risk factor for developing hepatic Angiosarcoma?

Accepted Answer

Vinyl chloride — Hepatic angiosarcoma is specifically associated with exposure to vinyl chloride, Thorotrast, and arsenic.

Question 10

Regarding Hepatocellular Carcinoma (HCC), which statement is correct concerning its variant forms?

Accepted Answer

Fibrolamellar HCC typically presents in young adults without cirrhosis — Fibrolamellar HCC is a distinct variant that occurs in young adults (20-40 years), is not associated with cirrhosis or HBV, and has a slightly better prognosis.

Question 11

What percentage of Non-Hodgkin Lymphomas are of B-cell origin?

Accepted Answer

85% — Approximately 85-90% of NHL cases are B-cell lymphomas; the remainder are T-cell or NK-cell lymphomas.

Question 12

Which is the most common subtype of B-cell NHL?

Accepted Answer

Diffuse Large B-Cell Lymphoma (DLBCL) — DLBCL is the most common form of NHL, accounting for about 30-40% of adult cases.

Question 13

A 60-year-old woman has painless lymphadenopathy. Biopsy shows BCL-2+, CD10+, CD20+ cells. What is the most likely diagnosis?

Accepted Answer

Follicular Lymphoma — Follicular lymphoma is characterized by a nodular growth pattern and expression of BCL-2 (due to t(14;18)) and germinal center markers like CD10.

Question 14

Which translocation is required for the diagnosis of Mantle Cell Lymphoma?

Accepted Answer

t(11;14) — Mantle Cell Lymphoma is defined by the t(11;14) translocation, which leads to overexpression of Cyclin D1.

Question 15

A patient with NHL has CD5+, CD19+, CD22+, CD23− immunophenotype. Which lymphoma does this suggest?

Accepted Answer

Mantle Cell Lymphoma — Mantle Cell Lymphoma is CD5+ and CD23- negative, whereas CLL/SLL is CD5+ and CD23+ positive.

Question 16

Which organism is directly implicated in the pathogenesis of gastric MALT lymphoma?

Accepted Answer

Helicobacter pylori — H. pylori infection causes chronic inflammation that provides the stimulus for the development of gastric MALT lymphoma.

Question 17

What is the first-line treatment for early-stage gastric MALT lymphoma?

Accepted Answer

Antibiotic eradication of H. pylori — In many cases of early gastric MALT lymphoma, eradication of H. pylori leads to complete regression of the tumor.

Question 18

Serum protein electrophoresis shows a monoclonal IgM spike. Bone marrow shows lymphoplasmacytoid infiltration. What mutation is likely?

Accepted Answer

MYD88 L265P — The MYD88 L265P mutation is found in over 90% of patients with Waldenström's Macroglobulinemia.

Question 19

Why is plasmapheresis particularly effective in hyperviscosity for Waldenström's compared to IgG myeloma?

Accepted Answer

IgM is primarily intravascular due to its large size (pentamer) — IgM is a large pentameric molecule that is mostly restricted to the intravascular space, making it easy to remove via plasmapheresis.

Question 20

A child from sub-Saharan Africa has a jaw mass with a 'starry sky' pattern on histology. What is the diagnosis?

Accepted Answer

Burkitt Lymphoma — Endemic Burkitt lymphoma typically presents as a jaw mass in African children and shows a 'starry sky' pattern (macrophages consuming debris among tumor cells).

Question 21

Which oncogene is overexpressed in virtually all cases of Burkitt lymphoma?

Accepted Answer

MYC — Burkitt lymphoma is characterized by the t(8;14) translocation (or variants), which places the MYC gene under the control of the Ig heavy chain promoter.

Question 22

What is the gold standard investigation for diagnosing NHL?

Accepted Answer

Excisional lymph node biopsy — Excisional biopsy is required to preserve the architecture of the lymph node, which is essential for classification (e.g., follicular vs. diffuse).

Question 23

In lymphoid neoplasms, what molecular event precedes malignant transformation?

Accepted Answer

Antigen receptor gene rearrangement — Rearrangement of antigen receptor genes (Ig for B cells, TCR for T cells) occurs early in lymphoid development; monoclonal rearrangements are markers of malignancy.

Question 24

A MALT lymphoma does NOT respond to H. pylori therapy. Which translocation explains this?

Accepted Answer

t(11;18) — The t(11;18) translocation in MALT lymphoma is associated with resistance to H. pylori eradication therapy.

Question 25

A 14-year-old male with a large mediastinal mass and TdT+ cells most likely has:

Accepted Answer

Precursor T-cell ALL/Lymphoma — Precursor T-ALL often presents in adolescent males as a mediastinal mass (thymic origin) and is TdT positive.

Question 26

Which translocation carries the worst prognosis in Precursor B-cell ALL?

Accepted Answer

t(9;22) — The t(9;22) (Philadelphia chromosome) in ALL carries a poor prognosis, whereas t(12;21) (ETV6-RUNX1) has a good prognosis.

Question 27

What are 'proliferation centres' in CLL/SLL histology?

Accepted Answer

Areas of large activated lymphocytes — Proliferation centers contain larger prolymphocytes and are pathognomonic for CLL/SLL in lymph node specimens.

Question 28

A patient with CLL has Hb 9g/dL and platelets 80×10⁹/L. What Binet stage is this?

Accepted Answer

Stage C — Binet Stage C is defined by the presence of anemia (Hb <10g/dL) or thrombocytopenia (platelets <100×10⁹/L).

Question 29

A 45-year-old alcoholic with epigastric pain and chalky white deposits on CT. Mechanism?

Accepted Answer

Enzymatic fat necrosis and saponification — In acute pancreatitis, lipase releases fatty acids which combine with calcium to form chalky white soap deposits (saponification).

Question 30

In acute pancreatitis, which histological finding distinguishes it from chronic pancreatitis?

Accepted Answer

Neutrophilic inflammation and proteolysis — Acute pancreatitis is characterized by neutrophilic inflammation, hemorrhage, and necrosis, whereas chronic is characterized by irreversible fibrosis and acinar loss.

Question 31

Mechanism of steatorrhea in chronic pancreatitis?

Accepted Answer

Exocrine pancreatic insufficiency — Loss of over 90% of pancreatic exocrine function (lipase production) leads to fat malabsorption and steatorrhea.

Question 32

Which genetic mutation is found in 90% of pancreatic ductal adenocarcinoma cases?

Accepted Answer

KRAS — KRAS is the most frequently mutated oncogene in pancreatic cancer, present in nearly all cases.

Question 33

Painless jaundice, palpable gallbladder (Courvoisier sign). Where is the tumor?

Accepted Answer

Head of pancreas — Tumors of the head of the pancreas obstruct the common bile duct, leading to obstructive jaundice and a distended gallbladder.

Question 34

Which precursor lesion leads to invasive pancreatic ductal adenocarcinoma?

Accepted Answer

PanIN — Pancreatic intraepithelial neoplasia (PanIN) is the well-recognized microscopic precursor to pancreatic ductal adenocarcinoma.

Question 35

What is the paraneoplastic phenomenon of migratory superficial thrombophlebitis?

Accepted Answer

Trousseau Syndrome — Trousseau syndrome (migratory thrombophlebitis) is often associated with visceral malignancies, particularly pancreatic cancer.

Question 36

KEY histological feature distinguishing serous cystadenoma from mucinous cystadenoma?

Accepted Answer

Presence of 'ovarian-type' stroma — Mucinous cystic neoplasms of the pancreas are characterized by a lining of mucin-producing cells and a distinct 'ovarian-type' subepithelial stroma.

Question 37

Which pancreatic cyst carries significant malignant potential?

Accepted Answer

Intraductal Papillary Mucinous Neoplasm (IPMN) — IPMNs and Mucinous cystic neoplasms are precursors to invasive carcinoma; serous cystadenomas are almost always benign.

Question 38

A pseudocyst differs from a true cyst in which way?

Accepted Answer

It lacks an epithelial lining — A pseudocyst is a collection of fluid and debris walled off by granulation tissue/fibrosis; it lacks the epithelial lining found in true cysts.

Question 39

In Type 1 Diabetes, which HLA haplotypes confer the strongest susceptibility?

Accepted Answer

HLA-DR3/DR4 — The MHC class II alleles HLA-DR3 and HLA-DR4 (specifically DQ8) are major genetic risk factors for T1DM.

Question 40

Role of CD8+ T cells in the pathogenesis of Type 1 Diabetes?

Accepted Answer

Directly killing beta cells via granzymes/perforin — T1DM is a T-cell mediated autoimmune disease where cytotoxic CD8+ T cells directly destroy insulin-producing beta cells.

Question 41

Which foramen ovale closes in approximately 75% of individuals at birth?

Accepted Answer

Foramen Ovale — The foramen ovale closes functionally at birth due to higher left atrial pressure; in about 25% of people, it remains 'probe patent'.

Question 42

Anatomical closure of the ductus arteriosus occurs through:

Accepted Answer

Fibrosis (Ligamentum arteriosum) — Functional closure occurs via muscle contraction; anatomical closure involves fibrosis to form the ligamentum arteriosum.

Question 43

Failure of which structure to cover the ostium secundum results in ASD?

Accepted Answer

Septum secundum — Ostium secundum ASD (the most common type) results from an inadequate growth of the septum secundum or excessive resorption of the septum primum.

Question 44

Which VSD type is specifically more common in Asian patients?

Accepted Answer

Subpulmonic (Supracristal) VSD — While membranous VSD is the most common overall, subpulmonic VSDs are notably more frequent in Asian populations.

Question 45

The fundamental embryological defect in Tetralogy of Fallot is:

Accepted Answer

Anterior and superior deviation of the infundibular septum — The single defect explaining all four features of ToF is the malalignment (anterosuperior displacement) of the infundibular (conal) septum.

Question 46

Apical displacement of which valve causes atrialization of the RV?

Accepted Answer

Tricuspid valve — Ebstein's anomaly involves downward displacement of the tricuspid valve leaflets into the right ventricle.

Question 47

In Transposition of Great Arteries, which embryological failure is responsible?

Accepted Answer

Failure of the conotruncal septum to spiral — TGA results from the failure of the conotruncal septum to follow its normal spiral course, leading to the aorta arising from the RV and PA from the LV.

Question 48

Chromosomal abnormality most specifically associated with coarctation of the aorta?

Accepted Answer

Turner Syndrome (45, X) — Turner syndrome is highly associated with the preductal (infantile) form of aortic coarctation.

Question 49

Persistent truncus arteriosus always occurs alongside which other defect?

Accepted Answer

VSD — Persistent truncus arteriosus results from failed septation of the outflow tract, which inherently includes a VSD.

Question 50

Which maternal teratogen is associated with Ebstein's anomaly?

Accepted Answer

Lithium — Maternal lithium use during the first trimester is a classic risk factor for Ebstein's anomaly.

Weekly Pathology Exam - March 7, 2026 (Section A: MCQs) | MCQ Quiz | OmpathStudy Kenya

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