neoplasm

Question 1

A 65-year-old right-handed woman began having neurological prob-
lems about 1 week ago. She began experiencing nausea, vomiting, and
numbness in the left hand and left foot. Today she had a generalized con-
vulsion, and since then she has had a throbbing headache that is worse
when she bends forward. On examination, the only deficits she has are loss
of double simultaneous tactile stimulation and left lower facial droop when
smiling. MRI reveals a lesion suggestive of a primary brain tumor.
The most common sources of primary brain tumors are
a. Glial cells
b. Neurons
c. Meningeal cells
d. Lymphocytes
e. Endothelial cells

Answer 1

The answer is a.( Bradley, p 1266.) Between 2 and 5% of all tumors
occurring in the general population are primary CNS tumors. In adults, the
most common primary brain tumor is the astrocytoma. In children, brain
tumors are more likely to arise in the posterior fossa. Even in childhood,
glial cell tumors, such as the cerebellar astrocytoma and the optic glioma,
are common

Question 2

A 65-year-old right-handed woman began having neurological prob-
lems about 1 week ago. She began experiencing nausea, vomiting, and
numbness in the left hand and left foot. Today she had a generalized con-
vulsion, and since then she has had a throbbing headache that is worse
when she bends forward. On examination, the only deficits she has are loss
of double simultaneous tactile stimulation and left lower facial droop when
smiling. MRI reveals a lesion suggestive of a primary brain tumor.
The most common type of primary brain tumor is
a. Meningioma
b. Astrocytoma
c. Lymphosarcoma
d. Oligodendroglioma
e. Medulloblastoma

Answer 2

The answer is b. ( Bradley, p 1266.) The most common primary
brain tumors are malignant astrocytomas. These are classified as grade 3 or
4. Grade 4 astrocytoma is more commonly called glioblastoma multiforme.
It is malignant in the very conventional sense that it invades adjacent tis-sue. This type of glial tumor is usually seen in adults; men are more sus-ceptible than women

Question 3

Most brain tumors in children are

a. Metastatic lesions from outside the central nervous system (CNS)
b. Oligodendrogliomas
c. Glioblastomas multiforme
d. Meningiomas
e. Infratentorial

Answer 3

The answer is e.( Bradley, p 1276.) The posterior fossa is the usual
location for brain tumors in children. Medulloblastomas, ependymomas,
and cerebellar (or brainstem) gliomas account for most of the tumors that
occur before puberty. Other common tumors developing intracranially in
children include optic gliomas and metastatic leukemias.

Question 4

The incidence of primary brain tumors in children—about 1 to 5 per
100,000 per year—is mainly accounted for by
a. Meningiomas and neurofibromas
b. Astrocytomas and medulloblastomas
c. Melanomas and choriocarcinomas
d. Gliomas and adenomas
e. Colloid cysts of the third ventricle

Answer 4

The answer is b. ( Rowland, p 297.) Meningiomas may occur in
childhood but are more likely to appear and become symptomatic during
adult life. Neurofibromas are not primary brain tumors, although schwan-noma of the eighth cranial nerve is sometimes incorrectly referred to as an
acoustic neurofibroma rather than an acoustic schwannoma. Colloid cysts
of the third ventricle are not necessarily neoplastic, although most are
assumed to have started as neoplasms rather than as developmental anom-alies. Glioma is a broad category that includes the astrocytoma. Adenomas,
such as pituitary adenomas, do develop in children, but much less com-monly than either astrocytomas or medulloblastomas. Central nervous sys-tem tumors account for a large proportion of the tumors seen in childhood.
In fact, they are second in frequency only to childhood leukemias and
account for 15 to 20% of childhood tumors.

Question 5

A 72-year-old woman has a head CT performed because of headaches.
It is significant for a left hemisphere mass with an overlying hyperostosis of
the skull. She most likely has which of the following?
a. Meningioma
b. Pituitary adenoma
c. Astrocytoma
d. Schwannoma
e. Hemangioblastoma

Answer 5

The answer is a.( Rowland, p 306.) Hyperostosis is thickening of the
bone and is much less commonly induced by tumors in or about the brain
than is thinning of the bone. Thinning occurs especially with pituitary ade-nomas, which may cause erosions in the floor of the sella turcica as an early
feature. Calcifications may develop in schwannomas or astrocytomas, but
both of these tumor types will usually cause bony erosions where they
impinge on the skull. Calcifications may develop in many primary or
metastatic brain tumors, but calcification sufficient to be readily seen on a
skull x-ray suggests an astrocytoma, meningioma, oligodendroglioma, or
metastatic tumor. Calcification can be visualized on CT scan in about 17%
of medulloblastomas. With meningiomas, hyperostosis may develop in the
bone adjacent to the tumor even if there is no infiltration of the bone by the
tumor

Question 6

A 9-year-old girl with papilledema and precocious puberty is most
likely to have
a. A pineal region tumor
b. An oligodendroglioma
c. A Kernohan class II astrocytoma
d. A brainstem glioma
e. An ependymoma

Answer 6

The answer is a.( Rowland, p 343.) The pineal region is the source
of an extraordinarily diverse group of tumor types, ranging from astrocy-tomas (derived from glial tissue) to chemodectomas (derived from sympa-thetic nervous tissue). Several different types of germ cell tumors arise from
the tissues in this region, presumably from embryonal cell rests. In the
United States, pineal tumors account for only 1% of intracranial tumors,
but one-third of these pineal tumors are germ cell tumors, including ger-minomas and choriocarcinomas.

Question 7

A 15-year-old boy has multiple angiomatoses of the retina and cysts
of the kidney and pancreas. The brain tumor that is most likely to develop
in this child is which of the following?
a. Glioblastoma multiforme
b. Meningioma
c. Hemangioblastoma
d. Ependymoma
e. Pinealoma

Answer 7

The answer is c. ( Rowland, p 375.) With von Hippel-Lindau syn-drome, the patient may exhibit tumors in multiple organs. In the brain,
hemangioblastomas are the tumors most likely to arise, and these tumors
are usually limited to the cerebellum or brainstem. Hemangioblastomas are
often multiple and become symptomatic by bleeding into themselves. The
initial episode of bleeding may prove lethal.

Question 8

A 56-year-old right-handed woman who had breast cancer 1 year
ago began having neurological problems about 1 week ago. She began
experiencing nausea, vomiting, and numbness in the right hand and foot.
Today she is experiencing crescendo pain in the left retroorbital area. Her
headache is throbbing and positional, particularly when she tries to bend
forward. The headache was intense in the morning, and at times it woke
her up last night. On examination, the only deficits are loss of double
simultaneous tactile stimulation and right lower facial droop when smiling.
The most appropriate next action would be to
a. Administer intravenous prochlorperazine
b. Give the patient a prescription for zolmitriptan
c. Make a follow-up appointment for next month
d. Order an electroencephalogram to rule out seizures
e. Get a brain MRI

Answer 8

The answer is e. ( Victor, pp 658–660, 684–686.) The headache is
typical of that caused by intracranial hypertension. Additionally, the
patient has focal neurological symptoms and signs. This creates particular
concern about a brain tumor or hemorrhage, and the patient should be
evaluated as soon as possible. An appointment next month is too late.
Intravenous prochlorperazine is a good treatment for status migrainosus;
however, this history is atypical for such a diagnosis and more serious
problems should be ruled out first in the emergency room. Zolmitriptan is a treatment for migraines. This history is not typical for migraine, and
zolmitriptan is also relatively contraindicated in patients with complex
migraine. This history is very atypical for seizures, and an electroen-cephalogram is not likely to provide useful information in this case

Question 9

A 56-year-old right-handed woman who had breast cancer 1 year
ago began having neurological problems about 1 week ago. She began
experiencing nausea, vomiting, and numbness in the right hand and foot.
Today she is experiencing crescendo pain in the left retroorbital area. Her
headache is throbbing and positional, particularly when she tries to bend
forward. The headache was intense in the morning, and at times it woke
her up last night. On examination, the only deficits are loss of double
simultaneous tactile stimulation and right lower facial droop when smiling.
Further evaluation reveals multiple brain masses. The most common
source of metastatic tumors to the brain is the
a. Breast
b. Lung
c. Kidney
d. Skin
e. Uterus

Answer 9

The answer is b.(Osborn, p 660.) The breast, lung, kidney, skin, and
uterus are all common sources of metastases to the brain. The incidences of
metastases from the lung and breast in women are very close, but with the
climbing rates of pulmonary carcinoma in women, the lung has become
the more common source. Skin lesions metastasizing to the brain include
malignant melanomas

Question 10

A 56-year-old right-handed woman who had breast cancer 1 year
ago began having neurological problems about 1 week ago. She began
experiencing nausea, vomiting, and numbness in the right hand and foot.
Today she is experiencing crescendo pain in the left retroorbital area. Her
headache is throbbing and positional, particularly when she tries to bend
forward. The headache was intense in the morning, and at times it woke
her up last night. On examination, the only deficits are loss of double
simultaneous tactile stimulation and right lower facial droop when smiling.
Metastatic lesions to the brain most often appear
a. At the gray-white junction
b. In the thalamus
c. In the posterior fossa
d. In the caudate
e. In the sella turcica

Answer 10

The answer is a.(Osborn, pp 660–661.) Metastatic lesions are spread
primarily by the vascular system. The gray-white junction (where the white
matter and the gray matter meet) is the interface at which blood-borne cells
are most likely to lodge and grow. No part of the brain is exempt from the
spread of metastases, but the cerebral hemispheres and the cerebellum are
especially vulnerable

Question 11

A 56-year-old right-handed woman who had breast cancer 1 year
ago began having neurological problems about 1 week ago. She began
experiencing nausea, vomiting, and numbness in the right hand and foot.
Today she is experiencing crescendo pain in the left retroorbital area. Her
headache is throbbing and positional, particularly when she tries to bend
forward. The headache was intense in the morning, and at times it woke
her up last night. On examination, the only deficits are loss of double
simultaneous tactile stimulation and right lower facial droop when smiling.
The shortest life expectancy with metastatic disease to the brain will
be found in the patient with metastatic
a. Malignant melanoma
b. Breast cancer
c. Lung cancer
d. Renal cancer
e. Prostate cancer

Answer 11

he answer is a.( Victor, pp 697–699.) The outlook with malignant
melanoma, breast cancer, lung cancer, or renal cancer metastatic to the
brain is poor and limited to a matter of months, but malignant melanoma
is especially grim because it is highly likely to bleed after it metastisizes to
the brain. Malignant melanoma and choriocarcinoma are likely to produce
lethal intracranial hemorrhages, and the former may in fact first become
apparent only after it has precipitated an intracranial hemorrhage. Prostate
cancer does not typically metastasize to the brain

Question 12

A 65-year-old right-handed woman began having neurological prob-
lems about 1 week ago. She began experiencing nausea, vomiting, and
numbness in the left hand and left foot. Today she had a generalized con-
vulsion, and since then she has had a throbbing headache that is worse
when she bends forward. On examination, the only deficits she has are loss
of double simultaneous tactile stimulation and left lower facial droop when
smiling. MRI reveals a lesion suggestive of a primary brain tumor.
The most common sources of primary brain tumors are
a. Glial cells
b. Neurons
c. Meningeal cells
d. Lymphocytes
e. Endothelial cells

Answer 12

The answer is a.( Bradley, p 1266.) Between 2 and 5% of all tumors
occurring in the general population are primary CNS tumors. In adults, the
most common primary brain tumor is the astrocytoma. In children, brain
tumors are more likely to arise in the posterior fossa. Even in childhood,
glial cell tumors, such as the cerebellar astrocytoma and the optic glioma,
are common

Question 13

A patient has a MRI performed and a colloid cyst of the third ventri-cle is identified. The most common complication of this lesion is

a. Bitemporal hemianopsia
b. Hydrocephalus
c. Gait ataxia
d. Optic atrophy
e. Oscillopsia

Answer 13

The answer is b. ( Victor, pp 708–709.) Colloid cysts may produce
transient or persistent obstruction of the flow of CSF. Because this is an
especially deep-seated lesion, it may be more practical to simply shunt the
fluid from the lateral ventricles rather than attempt to excise the cyst.
These cysts are usually lined with epithelial cells and may arise from a
variety of sources, including low-grade neoplasms that involute early in
their evolution

Question 14

The tumor type that is common in the brain of patients with AIDS,
but otherwise extremely rare, is
a. Lymphocytic leukemia
b. Metastatic lymphoma
c. Primary lymphoma
d. Kaposi’s sarcoma
e. Lymphosarcoma

Answer 14

The answer is c. ( Victor, pp 693–696.) Kaposi’s sarcoma is unusu-ally common in patients with AIDS, but it is rarely metastatic to the brain.Metastatic lymphomas producing meningeal lymphomatosis are not espe-
cially rare in the general population, but primary lymphomas (that is,
lymphomas apparently arising in the CNS) were rare before the AIDS epi-
demic. The primary brain lymphoma usually presents as a solitary mass
and can occur anywhere in the brain, but it does have a predilection for
the periventricular structures.

Question 15

A 37-year-old man presents with visual impairment. Examination
reveals a bitemporal hemianopsia. Which of the following tumors is most
likely responsible for this finding?
a. Optic glioma
b. Occipital astrocytoma
c. Brainstem glioma
d. Pituitary adenoma
e. Sphenoid wing meningioma

Answer 15

The answer is d.( Victor, p 714.) With bitemporal hemianopsia, the
visual fields in both eyes are impaired, but only the temporal quadrants of
the field in each eye are affected. Pressure on the optic chiasm inferiorly by
a tumor arising in or near the sella turcica will crush the fibers crossing in
the chiasm from the medial aspects of the optic nerves. The most medial
fibers in both optic nerves are contributed by the nasal aspects of the
retina. The nasal or medial aspects of the retina receive light from the tem-poral or lateral aspects of the visual field.

Question 16

A 9-year-old girl presents with precocious puberty and episodes of
uncontrollable laughter. Which of the following mass lesions might explain
her symptoms?
a. Craniopharyngioma
b. Choroid plexus papilloma
c. Giant aneurysm
d. Metastatic carcinoma
e. Hypothalamic hamartoma

Answer 16

The answer is e. (Swaiman, pp 1058–1050. Victor, pp 594–595.)
Hypothalamic hamartomas are nonneoplastic malformations involving
neurons and glia in the region of the hypothalamus. They may be discov-ered incidentally, either on imaging performed for other reasons or at
autopsy, or they may cause symptoms referable to the hypothalamus. Most
often, the latter involves neuroendocrine functions, causing precocious
puberty or acromegaly due to overproduction of growth hormone–releas-ing hormone. Patients may also experience paroxysms of laughter, known
as gelastic seizures. They may be cured surgically. Craniopharyngiomas are
epithelial neoplasms arising in the sellar and third ventricular regions.
They may cause hypopituitarism and visual field disturbances. Choroid
plexus papillomas usually develop intraventricularly and do not extend
down into the sella turcica. These tumors affect both children and adults,
but they are rare. They are benign if they are surgically accessible and are
extirpated early in their evolution. Giant aneurysms occur in many loca-tions, but typically do not cause gelastic seizures or precocious puberty.
Metastatic carcinoma generally occurs in older patients and would not be
expected to cause these symptoms.

Question 17

With an ependymoma of the posterior fossa, the patient is at risk of
dying because of
a. Transforaminal herniation
b. Emboli from the tumor
c. Vascular occlusion by the tumor
d. Hemorrhagic necrosis of the tumor
e. Status epilepticus

Answer 17

The answer is a.( Bradley, p 1062.) As a tumor of the posterior fossa
enlarges, the contents of the posterior fossa will be compressed and ulti-mately forced upward or downward. If the herniation is upward, it is called transtentorial because it is across the tentorium cerebelli. If it is
downward, it is called transforaminal because it is across the foramen
magnum. Ependymomas are not especially vulnerable to hemorrhagic
necrosis. Tumors in the posterior fossa generally do not produce seizures.

Question 18

A 30-year-old man with the acquired immune deficiency syndrome
(AIDS) develops headaches and left hemiparesis and is found to have a
right frontal white matter homogeneously enhancing lesion.  (SELECT 1
TUMOR
a. Medulloblastoma
b. Oligodendroglioma
c. Optic glioma
d. Carcinomatous meningitis
e. Schwannoma
f. Choriocarcinoma
g. Metastatic carcinoma
h. Pineocytoma
i. Primary CNS lymphoma

Answer 18

The answer is i. ( Bradley, p 1412.) Patients with AIDS are at risk for
numerous CNS infections, but have an increased frequency of only two
tumor types: lymphoma and Kaposi’s sarcoma. KS may metastasize to the
CNS, but lymphoma is routinely primary to the CNS. This tumor may pro-duce blindness through direct invasion of the optic nerve.

Question 19

A 4-year-old boy presents with ataxia, lethargy, and obstructive hy-drocephalus. (SELECT 1 TUMOR)

a. Medulloblastoma
b. Oligodendroglioma
c. Optic glioma
d. Carcinomatous meningitis
e. Schwannoma
f. Choriocarcinoma
g. Metastatic carcinoma
h. Pineocytoma
i. Primary CNS lymphoma

Answer 19

The answer is a. (Swaiman, pp 1065–1067.) Medulloblastomas are
one of the most common CNS tumors of childhood. They typically develop
in the cerebellum, causing ataxia. Astrocytomas may also occur in children
infratentorially, primarily in the cerebellum and brainstem. In either loca-tion, hydrocephalus may develop because of obstruction at the level of the
fourth ventricle. The astrocytoma that develops in the cerebellum is usually
cystic. Medulloblastomas are invariably infratentorial, at least initially. They
may extend supratentorially or become disseminated supratentorially
through seeding of cells carried in the CSF. Ependymomas, another com-mon tumor type in children, are derived from the lining of the ventricles
and also carry the risk of hydrocephalus and seeding throughout the CNS.

Question 20

A 16-year-old boy with café au lait spots and cutaneous nodules
complains of decreased vision in his left eye. (SELECT 1 TUMOR)
a. Medulloblastoma
b. Oligodendroglioma
c. Optic glioma
d. Carcinomatous meningitis
e. Schwannoma
f. Choriocarcinoma
g. Metastatic carcinoma
h. Pineocytoma
i. Primary CNS lymphoma

Answer 20

The answer is c.( Victor, p 719.) The neurofibromatoses are a pair of
hereditary neurocutaneous syndromes that result in a variety of congenital
and later-occurring abnormalities and neoplasms affecting the skin, ner-vous system, and other organs. Neurofibromatosis (NF) type 1, also called
peripheral NF, is characterized by café au lait spots, which are light to dark
brown spots found on the skin; multiple cutaneous and subcutaneous
tumors; bone cysts; sphenoid bone dysgenesis; precocious puberty;
pheochromocytoma; syringomyelia; glial nodules; cortical dysgenesis; and
macrocephaly. Optic nerve tumors are a particularly worrisome complica-tion, and may produce blindness in children.

Question 21

A 55-year-old woman presents with mild unsteadiness, tinnitus, and
hearing loss. (SELECT 1 TUMOR)
a. Medulloblastoma
b. Oligodendroglioma
c. Optic glioma
d. Carcinomatous meningitis
e. Schwannoma
f. Choriocarcinoma
g. Metastatic carcinoma
h. Pineocytoma
i. Primary CNS lymphoma

Answer 21

The answer is e. ( Victor, pp 709–712.) Schwannomas usually
develop on the vestibular division of cranial nerve VIII and are pathologi-cally derived from Schwann cells rather than nerve tissue, and are therefore
more appropriately called vestibular schwannomas than acoustic neuromas, the traditional name. Although this is not the division of the nerve
that carries information from the cochlea, the cochlear division is crushed
as the tumor expands. This type of tumor is especially likely with neurofi-
bromatosis type 2, a hereditary disorder characterized by a variety of
tumors in the skin and nervous system.

Question 22

A 13-year-old girl has headaches and diplopia. On examination, 
she has impaired upward gaze, lid retraction, and convergence-retraction
nystagmus. Her pupils react on convergence but not to light.  (SELECT 1
TUMOR)
a. Medulloblastoma
b. Oligodendroglioma
c. Optic glioma
d. Carcinomatous meningitis
e. Schwannoma
f. Choriocarcinoma
g. Metastatic carcinoma
h. Pineocytoma
i. Primary CNS lymphoma

Answer 22

The answer is h.( Victor, pp 705–708.) Pineocytomas are histologi-cally benign lesions affecting the region of the pineal gland. They arise
from the parenchymal cells of the pineal gland. This patient’s symptoms
and signs constitute Parinaud syndrome, which may include loss of verti-cal gaze, loss of pupillary light reflex, lid retraction, and convergence-retraction nystagmus, in which the eyes appear to jerk back into the orbit
on attempted upgaze. This syndrome occurs in lesions due to involvement
of the dorsal midbrain in the region of the superior colliculus. Other
tumors appearing in the pineal region that can produce a similar clinical
picture include germ cell tumors (germinomas), teratomas, and gliomas.
Malignant pineal tumors, or pineoblastomas, may also occur, and are sim-ilar histologically to medulloblastomas.

Question 23

A 67-year-old woman has a 2-month history of progressive gait dis-turbance. On exam, she has dysmetria of the limbs; a wide-based, unsteady
gait; and hypermetric saccades. A hard, firm breast lump is discovered.
(SELECT 1 DISORDER)
a. Paraneoplastic cerebellar degeneration
b. Limbic encephalitis
c. Dorsal root ganglionopathy
d. Hypercalcemia
e. Cancer-associated retinopathy
f. Pseudotumor cerebri
g. Motor neuron disease
h. Guillain-Barré syndrome
i. Paraproteinemic neuropathy
j. Opsoclonus-myoclonus
k. Stiff man syndrome
l. Lambert-Eaton myasthenic syndrome
m. Myasthenia gravis

Answer 23

The answer is a. ( Victor, pp 724–725.) Paraneoplastic cerebellar
degeneration (PCD) is characterized by subacute and relentlessly progres-sive ataxia, dysarthria, and nystagmus. Myoclonus, opsoclonus (irregular
jerking of the eyes in all directions), diplopia, vertigo, and hearing loss may
also occur. Imaging may eventually reveal cerebellar atrophy, and pathol-ogy will disclose loss of Purkinje cells in the cerebellum as the primary
abnormality. The most common associated tumor types are small cell car-cinoma of the lung, ovarian carcinoma, and lymphoma, in that order.
Approximately 50% of patients may harbor anti–Purkinje cell antibodies
(called anti-Yo antibodies), and these are especially commonly found in
women with breast cancer or other gynecologic malignancies. Interestingly,
the symptoms of PCD often precede the symptoms of the underlying
tumor itself, leading to speculation that the immune reaction that damages
the nervous system may, in fact, be protective against the tumor

Question 24

A 70-year-old man with a history of lung cancer develops nausea and
vomiting and then becomes lethargic. On exam, he is lethargic but arous-able, and disoriented and inattentive. He is weak proximally and has
diminished reflexes. (SELECT 1 DISORDER)
a. Paraneoplastic cerebellar degeneration
b. Limbic encephalitis
c. Dorsal root ganglionopathy
d. Hypercalcemia
e. Cancer-associated retinopathy
f. Pseudotumor cerebri
g. Motor neuron disease
h. Guillain-Barré syndrome
i. Paraproteinemic neuropathy
j. Opsoclonus-myoclonus
k. Stiff man syndrome
l. Lambert-Eaton myasthenic syndrome
m. Myasthenia gravis

Answer 24

The answer is d. ( Bradley, p 1491.) Hypercalcemia may occur as a
complication of cancer in up to 5% of patients. It may be a result of
parathyroid-related peptide secreted by the tumor itself (usually a lung
cancer) or of bone destruction by metastatic disease. The elevated serum calcium decreases membrane excitability, leading to the clinical syndrome
of fatigability, lethargy, generalized weakness, and areflexia. In more severe
cases, coma and even convulsions can occur. Symptoms usually do not
occur until levels reach 14 mg/dL or higher.

Question 25

A 57-year-old woman with a history of smoking has a 3-month his-tory of hip and shoulder weakness. She also complains of xerostomia. There
are no sensory symptoms, and she is cognitively intact. On exam, she is
orthostatic. There is proximal muscle weakness, but she has increasing mus-cle strength with repetitive activity of her muscles. Eye movements are nor-mal.  (SELECT 1 DISORDER)
a. Paraneoplastic cerebellar degeneration
b. Limbic encephalitis
c. Dorsal root ganglionopathy
d. Hypercalcemia
e. Cancer-associated retinopathy
f. Pseudotumor cerebri
g. Motor neuron disease
h. Guillain-Barré syndrome
i. Paraproteinemic neuropathy
j. Opsoclonus-myoclonus
k. Stiff man syndrome
l. Lambert-Eaton myasthenic syndrome
m. Myasthenia gravis

Answer 25

The answer is l.( Victor, pp 1547–1549.) The Lambert-Eaton myas-thenic syndrome (LEMS) shares some features with myasthenia gravis,
notably proximal muscle weakness. It usually develops subacutely, however,
and spares the bulbar musculature and eyes. There is also little response to
anticholinesterase drugs. A characteristic feature is the increase in strength
briefly after repeated muscle activation. Most cases are associated with an
underlying oat cell carcinoma of the lung or other malignancy. In other
cases, LEMS may be associated with other autoimmune illness. The under-lying defect is the loss of function of the voltage-sensitive calcium channels
in the presynaptic nerve terminal at the neuromuscular junction, due to
cross-linking and aggregation by pathologic IgG autoantibodies. Various
immune-modulating therapies, as well as 3,4-diaminopyridine, have been
used with varying success. Removal of the underlying malignancy may also
be curative.

Question 26

A 65-year-old woman develops pain and paresthesias in her feet. On
examination, she has loss of reflexes, stocking distribution sensory loss,
and mild distal weakness. Serum protein electrophoresis reveals a mono-clonal gammopathy, and bone marrow biopsy reveals plasma cell dyscrasia.
(SELECT 1 DISORDER)
a. Paraneoplastic cerebellar degeneration
b. Limbic encephalitis
c. Dorsal root ganglionopathy
d. Hypercalcemia
e. Cancer-associated retinopathy
f. Pseudotumor cerebri
g. Motor neuron disease
h. Guillain-Barré syndrome
i. Paraproteinemic neuropathy
j. Opsoclonus-myoclonus
k. Stiff man syndrome
l. Lambert-Eaton myasthenic syndrome
m. Myasthenia gravis

Answer 26

The answer is i. ( Bradley, pp 2091–2092.) Polyneuropathy may
occur in up to 15% of patients with multiple myeloma. This generally takes
the form of a chronic distal symmetrical sensory or sensorimotor neuropa-thy. In some cases, the neuropathy progresses more aggressively, and the
patient becomes confined to a wheelchair. Spinal fluid protein may be ele-vated, and the illness has the appearance of a chronic inflammatory
demyelinating polyneuropathy. Up to 20% of patients referred for evalua-tion of polyneuropathy may have an underlying monoclonal paraproteine-mia. In the absence of an obvious malignancy, this is called a monoclonal
gammopathy of undetermined significance, but a hematologic malignancy
may later turn up in as many as one-third of such patients