LATEST PATHOLOGY - PEDIATRIC
PATHOLOGY CERTIFICATION EXAM OFFERED
BY AMERICAN BOARD OF PATHOLOGY (ABMS)
| COMPLETE EXAM Q&A WITH RATIONALES
1. A newborn presents with respiratory distress,
failure to pass meconium, and abdominal distension.
Rectal biopsy shows absence of ganglion cells in the
submucosal and myenteric plexuses, with
hypertrophic nerve trunks. What is the most likely
diagnosis?
A) Hirschsprung disease (aganglionic megacolon)
B) Meconium ileus (cystic fibrosis)
C) Intestinal atresia
D) Neuronal intestinal dysplasia (NID)
Correct answer: A
Rationale: Hirschsprung disease (HSCR) is caused by
failure of neural crest cell migration to the distal
colon. Aganglionic segment (rectum always involved)
shows hypertrophic nerve trunks. Suction rectal
biopsy (acetylcholinesterase histochemistry) is
diagnostic.
,2. A 2-year-old child presents with failure to thrive,
hepatosplenomegaly, and progressive
neurodegeneration. Bone marrow biopsy shows foam
cells and sea-blue histiocytes. Enzyme assay shows
acid sphingomyelinase deficiency. What is the most
likely diagnosis?
A) Niemann-Pick disease type A (acid
sphingomyelinase deficiency)
B) Gaucher disease (type 2)
C) Tay-Sachs disease (hexosaminidase A deficiency)
D) Neimann-Pick type C (NPC1, cholesterol
trafficking)
Correct answer: A
Rationale: Niemann-Pick type A (acute
neuronopathic) presents in infancy with
organomegaly, neurodegeneration, cherry-red spot,
and foam cells (sphingomyelin accumulation). Acid
sphingomyelinase (SMPD1) deficient. Type C (D) is a
different disorder (NPC1/NPC2).
3. A 4-month-old infant presents with hypotonia,
hepatomegaly, and coarse facial features. Skeletal
survey shows dysostosis multiplex (abnormal
vertebral bodies, oar-shaped ribs). Urine
glycosaminoglycans (GAGs) are elevated. What is the
most likely diagnosis?
,A) Hurler syndrome (MPS I, alpha-L-iduronidase
deficiency)
B) Hunter syndrome (MPS II, iduronate sulfatase
deficiency)
C) Sanfilippo syndrome (MPS III, heparan sulfate)
D) Morquio syndrome (MPS IV, keratan sulfate)
Correct answer: A
Rationale: Hurler syndrome (MPS I) presents in
infancy with coarse facies, organomegaly, dysostosis
multiplex, neurodegeneration, and elevated urinary
GAGs (dermatan/heparan sulfate). Enzyme
replacement therapy available.
4. A 2-day-old infant presents with jaundice,
hepatosplenomegaly, and petechiae. TORCH screen
is positive for cytomegalovirus (CMV). Which
histologic finding is most characteristic of congenital
CMV infection?
A) Owl's eye intranuclear inclusions in renal tubular
epithelial cells
B) Periventricular calcifications (on head ultrasound)
C) Sensorineural hearing loss
D) Giant cell hepatitis with multinucleated
hepatocytes
, Correct answer: A
Rationale: Congenital CMV (most common congenital
infection) shows "owl's eye" intranuclear inclusions
(with halo) in renal tubules, hepatocytes, and lungs.
Periventricular calcifications (B) are more typical of
congenital toxoplasmosis.
5. A stillborn infant is delivered at 38 weeks gestation
with hydrops fetalis (anasarca, pleural effusions,
ascites). The placenta is large, pale, and edematous.
Microscopy shows nucleated red blood cells
(erythroblasts) in fetal vessels. Maternal blood type is
O negative. What is the most likely cause?
A) Rh hemolytic disease (erythroblastosis fetalis)
B) Parvovirus B19 infection
C) Alpha-thalassemia major (homozygous alpha-zero)
D) Congenital heart disease
Correct answer: A
Rationale: Rh hemolytic disease (anti-D) causes
severe hydrops fetalis with erythroblastosis
(nucleated RBCs) in fetal blood and extramedullary
hematopoiesis. Placenta shows edema and
erythroblasts. Prevention with Rh immune globulin
(RhoGAM).
PATHOLOGY CERTIFICATION EXAM OFFERED
BY AMERICAN BOARD OF PATHOLOGY (ABMS)
| COMPLETE EXAM Q&A WITH RATIONALES
1. A newborn presents with respiratory distress,
failure to pass meconium, and abdominal distension.
Rectal biopsy shows absence of ganglion cells in the
submucosal and myenteric plexuses, with
hypertrophic nerve trunks. What is the most likely
diagnosis?
A) Hirschsprung disease (aganglionic megacolon)
B) Meconium ileus (cystic fibrosis)
C) Intestinal atresia
D) Neuronal intestinal dysplasia (NID)
Correct answer: A
Rationale: Hirschsprung disease (HSCR) is caused by
failure of neural crest cell migration to the distal
colon. Aganglionic segment (rectum always involved)
shows hypertrophic nerve trunks. Suction rectal
biopsy (acetylcholinesterase histochemistry) is
diagnostic.
,2. A 2-year-old child presents with failure to thrive,
hepatosplenomegaly, and progressive
neurodegeneration. Bone marrow biopsy shows foam
cells and sea-blue histiocytes. Enzyme assay shows
acid sphingomyelinase deficiency. What is the most
likely diagnosis?
A) Niemann-Pick disease type A (acid
sphingomyelinase deficiency)
B) Gaucher disease (type 2)
C) Tay-Sachs disease (hexosaminidase A deficiency)
D) Neimann-Pick type C (NPC1, cholesterol
trafficking)
Correct answer: A
Rationale: Niemann-Pick type A (acute
neuronopathic) presents in infancy with
organomegaly, neurodegeneration, cherry-red spot,
and foam cells (sphingomyelin accumulation). Acid
sphingomyelinase (SMPD1) deficient. Type C (D) is a
different disorder (NPC1/NPC2).
3. A 4-month-old infant presents with hypotonia,
hepatomegaly, and coarse facial features. Skeletal
survey shows dysostosis multiplex (abnormal
vertebral bodies, oar-shaped ribs). Urine
glycosaminoglycans (GAGs) are elevated. What is the
most likely diagnosis?
,A) Hurler syndrome (MPS I, alpha-L-iduronidase
deficiency)
B) Hunter syndrome (MPS II, iduronate sulfatase
deficiency)
C) Sanfilippo syndrome (MPS III, heparan sulfate)
D) Morquio syndrome (MPS IV, keratan sulfate)
Correct answer: A
Rationale: Hurler syndrome (MPS I) presents in
infancy with coarse facies, organomegaly, dysostosis
multiplex, neurodegeneration, and elevated urinary
GAGs (dermatan/heparan sulfate). Enzyme
replacement therapy available.
4. A 2-day-old infant presents with jaundice,
hepatosplenomegaly, and petechiae. TORCH screen
is positive for cytomegalovirus (CMV). Which
histologic finding is most characteristic of congenital
CMV infection?
A) Owl's eye intranuclear inclusions in renal tubular
epithelial cells
B) Periventricular calcifications (on head ultrasound)
C) Sensorineural hearing loss
D) Giant cell hepatitis with multinucleated
hepatocytes
, Correct answer: A
Rationale: Congenital CMV (most common congenital
infection) shows "owl's eye" intranuclear inclusions
(with halo) in renal tubules, hepatocytes, and lungs.
Periventricular calcifications (B) are more typical of
congenital toxoplasmosis.
5. A stillborn infant is delivered at 38 weeks gestation
with hydrops fetalis (anasarca, pleural effusions,
ascites). The placenta is large, pale, and edematous.
Microscopy shows nucleated red blood cells
(erythroblasts) in fetal vessels. Maternal blood type is
O negative. What is the most likely cause?
A) Rh hemolytic disease (erythroblastosis fetalis)
B) Parvovirus B19 infection
C) Alpha-thalassemia major (homozygous alpha-zero)
D) Congenital heart disease
Correct answer: A
Rationale: Rh hemolytic disease (anti-D) causes
severe hydrops fetalis with erythroblastosis
(nucleated RBCs) in fetal blood and extramedullary
hematopoiesis. Placenta shows edema and
erythroblasts. Prevention with Rh immune globulin
(RhoGAM).
