USMLE Step 1 Medical Subject
Review: Pathology CNS
A 10-year-old boy with a history of epilepsy and intellectual disability is brought to a
specialty clinic for evaluation. Physical examination is remarkable for several ovoid
hypopigmented areas on the trunk and large numbers of red and yellow papules on
the face, particularly near the mouth. Biopsy of the papules demonstrates
angiofibromata. This patient is most likely to have which of the following central
nervous system pathologies? - ANS-Large cortical hamartomas
\10-year-old girl presents with severe headache and ataxia. Neuroradiologic imaging
reveals a tumor in the cerebellum. Microscopically, there are bipolar fibrillated and
elongated cells packed in bundles with perivascular arrangements. There are stellate
cells with short processes with a lacy pattern and areas showing microcystic
changes. Also seen are Rosenthal fibers, granular hyaline deposits, and eosinophilic
intracytoplasmic bodies. What is the most likely diagnosis? - ANS-Cerebellar
astrocytoma
\12-year-old boy is brought to the pediatrician by his mother, who says that for a few
months, her son has had some episodes of confusion and makes some strange
movements with his hands. Findings at the physical exam are a brownish ring
around the cornea and splenomegaly. What part of his nervous system is most likely
affected? - ANS-Lenticular nuclei
\12-year-old boy is investigated for severe headache and is found to have an
intraventricular mass by CT scan. The mass is well demarcated with pushing
borders. Microscopically, the excised mass shows cells with nuclei showing open
chromatin with an inconspicuous nucleus and well-defined cytoplasm with tapering
processes. These cells are arranged in rosette-like nests and around the vessels,
forming pseudorosettes. Also seen are epithelial lined tubules. The delicate
processes are positive with PTAH staining and are positive for GFAP. What is the
most likely diagnosis in this case? - ANS-Ependymoma
\12-year-old boy is prepubescent and has grown to over two meters tall. An MRI of
his head reveals an extrasellar mass. A similar tumor appearing an a 40-year-old
woman would MOST likely result in which disease? - ANS-acromegaly
\12-year-old boy is prepubescent and has grown to over two meters tall. An MRI of
his head reveals an extrasellar mass. The boy's tall stature is MOST probably due to
which of the following physiologic processes? - ANS-pituitary adenoma secreting
elevated growth hormone
\16-year-old boy is over 7' tall. Skull films showed an enlargement of the sella
turcica. What is the most likely cause? - ANS-Acidophil adenoma of pituitary
\17-year-old boy was working as a caddie when he was struck by a golf ball on the
right temple just above and in front of the ear. The boy was transported unconscious
,to the hospital. In the emergency department, he briefly regained consciousness but
then lapsed into unconsciousness again. On examination, the right pupil was dilated
and there was decreased muscle tone in the left leg. A Babinski reflex was elicited
from the left leg but not from the right. Lumbar puncture revealed bloody CSF with
increased pressure. A skull radiograph revealed a compression fracture of the
anterior, inferior angle of the parietal bone. The MOST likely diagnosis of this patient
is extradural hemorrhage. If your diagnosis includes rupture or tearing of a blood
vessel, which vessel (or branch of it) is MOST likely damaged in this patient? -
ANS-middle meningeal artery
\17-year-old high school student had been recently experiencing visual problems.
When questioned by the physician, she mentioned that she had stopped
menstruating several months previously. A MRI-scan of her head showed an
abnormal mass just inferior to the hypothalamus. The MOST likely diagnosis is which
of the following? - ANS-tumor of the adenohypophysis
\2-year-old child became blind in the right eye and showed a yellow 'cat's eye' reflex
when light was shone into the pupil. Ophthalmoscopic examination revealed a white
mass projecting from the retina. The MOST likely diagnosis is which of the following?
- ANS-retinoblastoma
\2-year-old girl presents because her mother noticed some kind of abnormality in her
daughter's right pupil. On examination, the right pupil appears white and there is
strabismus. The computed tomography reveals a growth behind the lens measuring
3 cm in diameter. Refer to the image for the microscopic picture of the enucleated
tumor. What is the most likely diagnosis? - ANS-Retinoblastoma
\20-year-old college student recently noticed difficulty with controlling muscles on the
right side of his face. Additionally, he had become extremely sensitive to loud noises
on his right side. He went to the campus health facilities, where a physician observed
right-sided hyperacusis, inability of the right eyelid to close, loss of taste sensation
from the right, anterior portion of the tongue, and weakness of upper and lower facial
muscles on the right side of the face. He made a prompt diagnosis of Bell's palsy
and advised the patient to get some rest but not to worry too much. Bell's palsy can
occur as a result of inflammation of which of the following nerves? - ANS-facial
\23-year-old English foreign exchange student was living with an American family
near Ames, Iowa. He had majored in agricultural sciences and international trade
during his studies in England. His health has always been good, with an appetite for
typical American junk foods and bland English dishes. Prior to his visit to the U.S., he
started having difficulty focusing on his studies. His difficulties, which included poor
eyesight, decreased coordination, and muscle spasms, progressed during his U.S.
visit the following year. His condition rapidly deteriorated over the next six months,
resulting in his hospitalization. Tests of his blood, sputum, CSF, and x-rays all were
negative for bacterial pathogens. He went into a coma, was hospitalized, and died a
month later. An autopsy of brain tissue showed a spongiform encephalopathic
disease. The patientï¾'s disease was MOST likely acquired from which of the
following source - ANS-consuming contaminated meat
, \23-year-old man presents with difficulty walking and frequent falls for the last 3
months. He also has a 3-month history of increased thirst and urinary frequency.
There is no history of fever, weight loss, and no history of any major illness in the
past. He has mild palpitations on walking. On examination, pulse 86/min and blood
pressure 130/80mm of Hg are noted. Abdominal, respiratory, and cardiovascular
system examinations are within normal limits. CNS examination shows nystagmus,
loss of fast saccadic eye movements, absent deep tendon reflexes, and upward
plantar reflexes. There is weakness in distal limb muscles and some sensory loss of
fine touch and vibrations. He has ataxic gait, but no spasticity. MRI of the brain is
normal. He denies alcohol consumption or any other illicit drug use. This condition
may be associated with a deficiency of what vitamin? - ANS-Vitamin E
\23-year-old woman presents due to a headache that appears to be bilateral, and
she describes it as a "tight" feeling around her head. She started physician assistant
school 2 months ago and has been really stressed out. Upon physical exam, no
abnormal findings are found. Additionally, all laboratory findings are within normal
limits. What is the most likely diagnosis? - ANS-Tension headache
\28-year-old man is brought into the emergency room after a single episode of
seizure. He has a history of acute onset of headache with high-grade fever. On
examination, the patient appeared extremely drowsy and revealed a right-sided
hemiplegia. A CT scan and CSF examination confirmed a viral infection of the brain
parenchyma. What is the most likely diagnosis? - ANS-Encephalitis
\28-year-old woman had loss of position sense, sensation, and fine motor control in
her upper extremities gradually increasing over months. A CT scan showed a mass
in her cervical spine with the attenuation coefficients of lipid. Operation (Figure
G10.4 A - left) removed a mass (Figure G10.4 B - right). The clinical features and
appearance of the disease are MOST likely which of the following? - ANS-lipoma
\29-year-old woman visits her obstetrician/gynecologist. She and her husband have
been trying unsuccessfully to have a child. She also notes weight gain, increased
facial hair, and lack of menses. A pelvic examination reveals normal external
genitalia but palpation reveals that both ovaries are enlarged. Her blood chemistry
shows elevated LH, decreased FSH, and abnormal steroid levels. The MOST likely
diagnosis is which of the following? - ANS-Stein-Leventhal syndrome
\3-year-old boy develops headaches and is brought to the family doctor.
Fundoscopic examination reveals papilledema; 1 retina also shows a very vascular
tumor. CT of the head demonstrates a cystic tumor of the cerebellum. This child has
a high likelihood of later developing what condition? - ANS-Bilateral renal cell
carcinoma
\3-year-old girl shows a white reflection from the surface of the retina upon
ophthalmologic examination. Biopsy of the lesion reveals retinoblastoma (Rb). The
Rb gene is which of the following types of gene? - ANS-tumor suppressor gene
\3-year-old girl shows a white reflection from the surface of the retina upon
ophthalmologic examination. Biopsy of the lesion reveals retinoblastoma (Rb).
Underphosphorylated Rb gene product has which significant characteristic? -
ANS-prevents mitosis
Review: Pathology CNS
A 10-year-old boy with a history of epilepsy and intellectual disability is brought to a
specialty clinic for evaluation. Physical examination is remarkable for several ovoid
hypopigmented areas on the trunk and large numbers of red and yellow papules on
the face, particularly near the mouth. Biopsy of the papules demonstrates
angiofibromata. This patient is most likely to have which of the following central
nervous system pathologies? - ANS-Large cortical hamartomas
\10-year-old girl presents with severe headache and ataxia. Neuroradiologic imaging
reveals a tumor in the cerebellum. Microscopically, there are bipolar fibrillated and
elongated cells packed in bundles with perivascular arrangements. There are stellate
cells with short processes with a lacy pattern and areas showing microcystic
changes. Also seen are Rosenthal fibers, granular hyaline deposits, and eosinophilic
intracytoplasmic bodies. What is the most likely diagnosis? - ANS-Cerebellar
astrocytoma
\12-year-old boy is brought to the pediatrician by his mother, who says that for a few
months, her son has had some episodes of confusion and makes some strange
movements with his hands. Findings at the physical exam are a brownish ring
around the cornea and splenomegaly. What part of his nervous system is most likely
affected? - ANS-Lenticular nuclei
\12-year-old boy is investigated for severe headache and is found to have an
intraventricular mass by CT scan. The mass is well demarcated with pushing
borders. Microscopically, the excised mass shows cells with nuclei showing open
chromatin with an inconspicuous nucleus and well-defined cytoplasm with tapering
processes. These cells are arranged in rosette-like nests and around the vessels,
forming pseudorosettes. Also seen are epithelial lined tubules. The delicate
processes are positive with PTAH staining and are positive for GFAP. What is the
most likely diagnosis in this case? - ANS-Ependymoma
\12-year-old boy is prepubescent and has grown to over two meters tall. An MRI of
his head reveals an extrasellar mass. A similar tumor appearing an a 40-year-old
woman would MOST likely result in which disease? - ANS-acromegaly
\12-year-old boy is prepubescent and has grown to over two meters tall. An MRI of
his head reveals an extrasellar mass. The boy's tall stature is MOST probably due to
which of the following physiologic processes? - ANS-pituitary adenoma secreting
elevated growth hormone
\16-year-old boy is over 7' tall. Skull films showed an enlargement of the sella
turcica. What is the most likely cause? - ANS-Acidophil adenoma of pituitary
\17-year-old boy was working as a caddie when he was struck by a golf ball on the
right temple just above and in front of the ear. The boy was transported unconscious
,to the hospital. In the emergency department, he briefly regained consciousness but
then lapsed into unconsciousness again. On examination, the right pupil was dilated
and there was decreased muscle tone in the left leg. A Babinski reflex was elicited
from the left leg but not from the right. Lumbar puncture revealed bloody CSF with
increased pressure. A skull radiograph revealed a compression fracture of the
anterior, inferior angle of the parietal bone. The MOST likely diagnosis of this patient
is extradural hemorrhage. If your diagnosis includes rupture or tearing of a blood
vessel, which vessel (or branch of it) is MOST likely damaged in this patient? -
ANS-middle meningeal artery
\17-year-old high school student had been recently experiencing visual problems.
When questioned by the physician, she mentioned that she had stopped
menstruating several months previously. A MRI-scan of her head showed an
abnormal mass just inferior to the hypothalamus. The MOST likely diagnosis is which
of the following? - ANS-tumor of the adenohypophysis
\2-year-old child became blind in the right eye and showed a yellow 'cat's eye' reflex
when light was shone into the pupil. Ophthalmoscopic examination revealed a white
mass projecting from the retina. The MOST likely diagnosis is which of the following?
- ANS-retinoblastoma
\2-year-old girl presents because her mother noticed some kind of abnormality in her
daughter's right pupil. On examination, the right pupil appears white and there is
strabismus. The computed tomography reveals a growth behind the lens measuring
3 cm in diameter. Refer to the image for the microscopic picture of the enucleated
tumor. What is the most likely diagnosis? - ANS-Retinoblastoma
\20-year-old college student recently noticed difficulty with controlling muscles on the
right side of his face. Additionally, he had become extremely sensitive to loud noises
on his right side. He went to the campus health facilities, where a physician observed
right-sided hyperacusis, inability of the right eyelid to close, loss of taste sensation
from the right, anterior portion of the tongue, and weakness of upper and lower facial
muscles on the right side of the face. He made a prompt diagnosis of Bell's palsy
and advised the patient to get some rest but not to worry too much. Bell's palsy can
occur as a result of inflammation of which of the following nerves? - ANS-facial
\23-year-old English foreign exchange student was living with an American family
near Ames, Iowa. He had majored in agricultural sciences and international trade
during his studies in England. His health has always been good, with an appetite for
typical American junk foods and bland English dishes. Prior to his visit to the U.S., he
started having difficulty focusing on his studies. His difficulties, which included poor
eyesight, decreased coordination, and muscle spasms, progressed during his U.S.
visit the following year. His condition rapidly deteriorated over the next six months,
resulting in his hospitalization. Tests of his blood, sputum, CSF, and x-rays all were
negative for bacterial pathogens. He went into a coma, was hospitalized, and died a
month later. An autopsy of brain tissue showed a spongiform encephalopathic
disease. The patientï¾'s disease was MOST likely acquired from which of the
following source - ANS-consuming contaminated meat
, \23-year-old man presents with difficulty walking and frequent falls for the last 3
months. He also has a 3-month history of increased thirst and urinary frequency.
There is no history of fever, weight loss, and no history of any major illness in the
past. He has mild palpitations on walking. On examination, pulse 86/min and blood
pressure 130/80mm of Hg are noted. Abdominal, respiratory, and cardiovascular
system examinations are within normal limits. CNS examination shows nystagmus,
loss of fast saccadic eye movements, absent deep tendon reflexes, and upward
plantar reflexes. There is weakness in distal limb muscles and some sensory loss of
fine touch and vibrations. He has ataxic gait, but no spasticity. MRI of the brain is
normal. He denies alcohol consumption or any other illicit drug use. This condition
may be associated with a deficiency of what vitamin? - ANS-Vitamin E
\23-year-old woman presents due to a headache that appears to be bilateral, and
she describes it as a "tight" feeling around her head. She started physician assistant
school 2 months ago and has been really stressed out. Upon physical exam, no
abnormal findings are found. Additionally, all laboratory findings are within normal
limits. What is the most likely diagnosis? - ANS-Tension headache
\28-year-old man is brought into the emergency room after a single episode of
seizure. He has a history of acute onset of headache with high-grade fever. On
examination, the patient appeared extremely drowsy and revealed a right-sided
hemiplegia. A CT scan and CSF examination confirmed a viral infection of the brain
parenchyma. What is the most likely diagnosis? - ANS-Encephalitis
\28-year-old woman had loss of position sense, sensation, and fine motor control in
her upper extremities gradually increasing over months. A CT scan showed a mass
in her cervical spine with the attenuation coefficients of lipid. Operation (Figure
G10.4 A - left) removed a mass (Figure G10.4 B - right). The clinical features and
appearance of the disease are MOST likely which of the following? - ANS-lipoma
\29-year-old woman visits her obstetrician/gynecologist. She and her husband have
been trying unsuccessfully to have a child. She also notes weight gain, increased
facial hair, and lack of menses. A pelvic examination reveals normal external
genitalia but palpation reveals that both ovaries are enlarged. Her blood chemistry
shows elevated LH, decreased FSH, and abnormal steroid levels. The MOST likely
diagnosis is which of the following? - ANS-Stein-Leventhal syndrome
\3-year-old boy develops headaches and is brought to the family doctor.
Fundoscopic examination reveals papilledema; 1 retina also shows a very vascular
tumor. CT of the head demonstrates a cystic tumor of the cerebellum. This child has
a high likelihood of later developing what condition? - ANS-Bilateral renal cell
carcinoma
\3-year-old girl shows a white reflection from the surface of the retina upon
ophthalmologic examination. Biopsy of the lesion reveals retinoblastoma (Rb). The
Rb gene is which of the following types of gene? - ANS-tumor suppressor gene
\3-year-old girl shows a white reflection from the surface of the retina upon
ophthalmologic examination. Biopsy of the lesion reveals retinoblastoma (Rb).
Underphosphorylated Rb gene product has which significant characteristic? -
ANS-prevents mitosis
