Tumor Flashcards

Question

A 9-month-old boy who is breast-fed is evaluated for scaphocephaly. Length and weight are in the 10th percentile, although occipitofrontal circumference is in the 80th percentile. He has a history of gastroesophageal reflux disease that is treated with antacids. X-ray films confirm sagittal synostosis. Which of the following is the most likely diagnosis? Answers: A. Crouzon syndrome B. Rickets C. Vitamin A deficiency D. Plagiocephaly E. Carpenter syndrome

Answer 1

Rickets ## Footnote Osteomalacia or rickets may result from altered 1,25-dihydroxyvitamin D bioavailability and/or deficiency of calcium or phosphorus. Moreovever, a rare but well-recognized cause of hypophosphatemia is the long-term ingestion of phosphate-binding aluminum- or magnesium- containing antacids. Antacids that contain aluminum or magnesium bind phosphate in the gut and result in markedly decreased phosphate absorption, leading to severe phosphate depletion. There is an increased risk of sagittal synostosis in hypophosphatemic rickets and related diseases in children. The appearance of the cranial vault in this type of synostosis can vary from that seen in nonsyndromic synostosis. In this setting, careful clinical and imaging follow-up is warranted.

Answer 2

**Paraganglioma** ## footnote This patient has pulsatile tinnitus, is showing signs of lower cranial nerve dysfunction and otoscopy reveals a “rising sun sign”. These findings are classic for a glomus tumor or paraganglioma. Paragangliomas are referred to as pheochromocytomas when they arise from the adrenal gland and are sometimes also called chemodectomas depending on their histologic morphology. The “Rising Sun” sign is the visualization of a red tumor along the floor of the middle ear and can be seen in a variety of otologic diseases. When blanchable, it is referred to as “Brown’s Sign” which is a specific finding for a glomus tympanicum tumor but can also be seen in glomus jugulare tumors. Cholesteatomas and schwannomas are tumors that can affect the middle ear but rarely cause lower cranial nerve dysfunction and are not associated with the Rising Sun sign. Chordomas of the skull base can cause lower cranial nerve dysfunction but usually not pulsatile tinnitus. Dural AV fistulas can cause pulsatile tinnitus but usually not other neurologic signs.

Answer 3

Diabetes ## Footnote Diabetic 3rd nerve palsies are the most common etiologic subset of 3rd nerve palsy in adults. Patients have pain and a pupil sparing 3 nerve palsy. 1. Ptosis: Due to paralysis of LPS (levator palpebrae superioris) muscle 2. 2. Ocular deviation: In case of third-nerve palsy, the lateral rectus and superior oblique are spared, and their unopposed action brings the eye in a “down and out” position. 3. 3. Pupil:In compressive third-nerve palsy, the pupil becomes fixed and dilated due to paralysis of sphincter pupillae. Ciliary muscle paralysis also leads to loss of accommodation. However, in ischemic lesions, the pupil is spared, and there is no loss of accommodation. 4. 4. Diplopia:This occurs due deviation of the affected eye resulting in the image falling on an extrafoveal point. However, due to ptosis the patient usually doesn’t complain of double vision as ptosis acts as a barrier to diplopia. Tolosa Hunt Syndrome is also hallmarked by orbital pain, however typically there is pupillary involvement, and often more than one nerve in the cavernous sinus involved. Compression from an aneurysm would have pupil involved 3 rd nerve palsy. Bells Palsy involves CN7 and would not cause Diplopia MG causes bilateral ptosis and is not painful

Answer 4

Lateralization of ACTH production by pituitary microadenoma ## Footnote Inferior petrosal sinus sampling (IPSS) involves sampling of ACTH levels from the petrosal veins that drain the pituitary gland and comparing ACTH levels with systemic blood levels to determine pituitary versus ectopic ACTH production. IPSS can be used to established lateralization (right versus left) of ACTH production which could guide surgical exploration when the microadenoma is not obvious on MRI.

Answer 5

Resection of nodule ## Footnote This patient has a cystic tumor of her posterior fossa. The lesions in her eyes and kidneys suggest she has von Hippel Lindau disease. This means the posterior fossa tumor is likely a hemangioblastoma which is symptomatic and should be resected. Observation is reasonable for smaller asymptomatic tumors in patients with VHL. Radiation is reserved for palliative cases. If the cyst is drained, it will likely recur as the underlying nodule continues to grow. Moreover, the nodule can be very vascular and minimally invasive drainage may result in hemorrhage. Bevacizumab is utilized for VHL patients with multiple lesions that are growing and not amenable to surgical resection.

Answer 6

Cerebellar mutism ## Footnote Cerebellar mutism syndrome typically develops after resection of midline cerebellar or intraventricular tumors in the posterior fossa (as shown in the image). The constellation of symptoms includes transient mutism, ataxia, hypotonia and irritability. This typically occurs in children, although there are reports of cerebellar mutism occurring in adults. Cerebellar mutism is thought to occur due to post-surgical injury to the dentato-thalamo-cortical tract. Supportive care and early rehabilitation are critical for recovery. Anomia and finger agnosia are characteristic of Gerstmann's Syndrome, resulting from dominant parietal damage. Temporary contralateral hemiparesis would be consistent with SMA syndrome. Alexia without agraphia is a type of disconnection syndrome, which can be caused by posterior corpus callosum damage.

Answer 7

Diabetes ## Footnote Diabetes mellitus and hypertension cause ischemic changes in the nerve and are the most common systemic causes of acquired nerve palsy 1. Ptosis: Due to paralysis of LPS (levator palpebrae superioris) muscle 2. Ocular deviation: In case of third-nerve palsy, the lateral rectus and superior oblique are spared, and their unopposed action brings the eye in a “down and out” position. 3. Pupil: In compressive third-nerve palsy, the pupil becomes fixed and dilated due to paralysis of sphincter pupillae. Ciliary muscle paralysis also leads to loss of accommodation. However, in ischemic lesions, the pupil is spared, and there is no loss of accommodation. 4. Diplopia: This occurs due deviation of the affected eye resulting in the image falling on an extrafoveal point. However, due to ptosis the patient usually doesn’t complain of double vision as ptosis acts as a barrier to diplopia.

Answer 8

60 Gy ## Footnote In Stupp et al. published in the NEJM in 2005, it was found that fractionated focal radiation at a dose of 2 Gy per fraction given one daily for five days per weeks over a period of six weeks, for a total of 60 Gy with concomitant chemotherapy consisting of temozolomide demonstrated a clinically meaningful and statistically significant survival benefit compared to radiotherapy alone. Among elderly patients, there is no evidence that conventionally fractionated radiation therapy (60 Gy in 30 fractions) is more efficacious than hypofractionated radiation therapy (eg, 40 Gy in 15 fractions over 3 weeks). Compared with conventionally fractionated radiation therapy, hypofractionated radiation therapy has been associated with superior survival and less corticosteroid requirement.

Answer 9

Short term memory loss ## Footnote The figure demonstrates a non-enhancing lesion in the roof of the third ventricle blocking the bilateral foramen of Monroe. CT imaging demonstrates hyperdensity. This is most consistent with a colloid cyst. The most common complication encountered post operatively is short term memory loss. This is due to proximity of the fornix to the cyst, which can be injured during resection. Often the memory loss is transient and returns within months after surgery. Expressive aphasia can occur from injury to the dominant inferior frontal lobe cortex. Seizures can occur from irritation to the brain secondary to open surgery. Mutism can occur following extensive injury to the corpus callosum. Disconnection syndrome can occur secondary to injury of the corpus callosum as a result of an interhemispheric approach to this lesion.

Answer 10

Immediate transsphenoidal resection ## Footnote The MRI images demonstrate evidence of pituitary apoplexy with significant expansion of the adenoma with compression of the optic chiasm cephalad and extension into the right cavernous sinus resulting in presentation of visual deterioration and ophthalmoplegia. Pituitary apoplexy defines hemorrhage or infarction of a preexisting pituitary adenoma resulting in rapid expansion of contents of the sella turcica. It can result in a classical constellation of symptoms characterized by sudden severe headaches, visual impairment, ophthalmoplegia, vomiting, and altered mental status. Hemodynamic stabilization with corticosteroid and necessary hormonal replacement followed by surgical decompression has been considered generally to be the best treatment course for apoplexy that results in neuro-ophthalmologic symptoms. There is controversy regarding the timing of surgery whether immediate decompression is necessary for the highest chance to restore neurological function, or surgery in the subacute period can also provide the same benefit. Most studies agree that surgical decompression within the subacute period (< 6-7 days) have the same overall outcome and chance for neurological recovery. In the absence of neurological deficits, conservative management may achieve similar results.

Answer 11

Germinoma ## Footnote Intracranial germinomas, also known as dysgerminomas or extra-gonadal seminomas, are a type of germ cell tumor and are predominantly seen in pediatric populations. They tend to occur in the midline, either at the pineal region (majority) or along the floor of the third ventricle/suprasellar region. The differential diagnosis for a pineal tumor is broad and includes tumors of pineal (pinealocytoma, pineoblastoma), germ cell (germinoma, embryonal carcinoma, endodermal sinus, choriocarcinoma, teratoma), glial (astrocytoma, glioblastoma, ependymoma, choroids plexus papilloma, etc.), and other (meningioma, dermoid, epidermoid, or arachnoid cyst) derivations. However, a synchronous pineal region and suprasellar tumor (as seen in this patient) is considered almost pathognomonic of a germinoma. Germinomas are tumors of young patients with a peak incidence of 10-12 years of age (90% of patients being younger than 20 at the time of diagnosis). They account for 3-5% of pediatric intracranial tumors but only 0.4-1% of intracranial tumors in adults. They are the most common tumor of the pineal region accounting for approximately 50% of all tumors, and the majority (73-86%) of intracranial germ cell tumor. Gender ratios are interestingly different depending on location. In the pineal region there is a marked male preponderance with a male to female ratio of 5-22:1 whereas in the suprasellar region, they are slightly more frequent in females with a male to female ratio of 1:1.3. Overall, due to the pineal region being most common, germinomas are seen more frequently in males. Presentation depends on location, with compression of the tectal plate leading to obstructive hydrocephalus and Parinaud syndrome, whereas involvement on the pituitary infundibulum leads to diabetes insipidus (most common), hypopituitarism (common) or optic chiasm compression or signs of intracranial hypertension. When the thalami and basal ganglia are involved, the presentation is often delayed with a larger tumor at diagnosis. Pure germinomas are commonly highly radiosensitive and are often treated without total surgical resection.

Answer 12

Meningioma ## Footnote Meningiomas can be positive for estrogen and progesterone receptors. Hemangiopericytomas can mimic meningioma but are hormone receptor negative. Many other CNS neoplasms can express hormone receptors including schwannoma, glioblastoma, and medulloblastoma but these are not markers typically used to identify these tumors.

Answer 13

Carotid cavernous fistula ## Footnote Carotid cavernous fistula (CCF) is an abnormal communication between the cavernous sinus and the carotid arterial system. Patients with CCF may initially present to an ophthalmologist with decreased vision, conjunctival chemosis, external ophthalmoplegia and proptosis. Graves disease is the most common cause of exophthalmos, however it is bilateral and non pulsatile. An orbital tumor could be a cause of pulsatile exophthalmos.

Answer 14

60Gy in 30 fractions ## Footnote In Stupp et al. published in the NEJM in 2005, it was found that fractionated focal radiation at a dose of 2 Gy per fraction given one daily for five days per weeks over a period of six weeks, for a total of 60 Gy with concomitant chemotherapy consisting of temozolomide demonstrated a clinically meaningful and statistically significant survival benefit compared to radiotherapy alone. Among elderly patients, there is no evidence that conventionally fractionated radiation therapy (60 Gy in 30 fractions) is more efficacious than hypofractionated radiation therapy (eg, 40 Gy in 15 fractions over 3 weeks). Compared with conventionally fractionated radiation therapy, hypofractionated radiation therapy has been associated with superior survival and less corticosteroid requirement.

Answer 15

Autosomal dominant ## Footnote This patient most likely has von Hippel Landau (VHL) disease, which demonstrates autosomal dominant inheritance based on a gene mutation found on chromosome 3. VHL is caused by a mutation of the tumor suppressor gene (pVHL). Patients with his condition have tumors that can arise in multiple organs. Most commonly, they have hemangioblastomas. Approximately 25-33% of patients harboring a hemangioblastoma have Von Hippel-Lindau disease. These lesions are highly vascular, and their removal requires meticulous dissection and cautious circumferential disruption of feeding arteries and draining veins. People with VHL can also have retinal angiomas, clear cell renal cell carcinoma, pancreatic neuroendocrine tumors and pheochromocytomas, which is likely the hypervascular adrenal lesion in this case. This patient has a hemangioblastoma of the spinal cord and posterior fossa. These are brightly enhancing lesions. These lesions usually have distinct borders between tumor and spinal cord. They may be cured by total surgical excision. Therefore, external beam radiotherapy or, conversely, conservative management are not indicated. Open biopsy is an option, but once the diagnosis of hemangioblastoma is confirmed, gross total excision should be undertaken.

Answer 16

Hormonal (thyroid and adrenal) supplementation followed by transsphenoidal resection. ## Footnote The presentation of acute vision loss and panhypopituitarism in the setting of known prolactinoma should raise suspicion for pituitary apoplexy. In addition, the presence of adrenal insufficiency with hypotension should suggest potential Addisonian crisis. The appropriate management would entail immediate adrenal and thyroid hormonal supplementation followed by sellar decompression if there is chiasmatic compression from hemorrhage.

Answer 17

Restriction of intake of free water

Answer 18

Excessive zinc ingestion ## Footnote Multiple factors, either hereditary or acquired, contribute to copper. The uptake of dietary copper into intestinal cells is via the Ctr1 transporter, located at the apical membrane aspect of intestinal cells and in most tissues. Copper is excreted from enterocytes into the blood via the Cu-ATPase, ATP7A, by trafficking the transporter towards the basolateral membrane. Although zinc absorption may occur by direct interaction with the Ctr1 transporter, its absorption is slightly different. With excessive zing ingestion, the elimination of excess zinc is slow and that, until such elimination occurs, the intestinal absorption of copper is blocked. Copper deficiency affects physiologic systems such as bone marrow hematopoiesis, optic nerve function, and the nervous system in general. Copper deficiency myeloneuropathy — A syndrome similar to the subacute combined degeneration of vitamin B12 deficiency can occur with acquired copper deficiency, which can result from gastrointestinal surgery, excessive zinc ingestion (eg, overuse of denture cream), and other causes. Most patients also have hematologic abnormalities.

Answer 19

Insulin like growth factor-1 (IGF-1) ## Footnote Acromegaly is most commonly the result of a GH secreting pituitary adenoma. GH acts on the liver to result in hypersecretion of IGF-1. Its diagnosis is confirmed by high levels of serum IGF-1, and is the diagnostic test of choice to rule out a diagnosis of acromegaly. IGF-1, rather than GH, is the serum marker used to rule out acromegaly because the serum levels are more constant during the day while GH levels can fluctuate significantly. Acromegaly treatment rests on normalization of serum IGF-1 levels, as this is the best reflection of adequate disease control. Somatostatin analogs may be used for the medical treatment of GH secreting tumors. Surgical resection is the treatment of choice, but in patients for whom surgery is contraindicated, the use of somatostatin analogs offers first line medical therapy.

Answer 20

Internuclear ophthalmoplegia ## Footnote Internuclear ophthalmoplgia (INO) is an ocular movement disorder caused by a lesion of the medial longitudinal fasciculus (MLF) resulting in impaired ipsilateral adduction and nystagmus of the abducting eye. 30% of cases are due to infarction, 30% from demyelination, and the rest from a variety of infectious, iatrogenic or vascular reasons. Saccades are initiated by the frontal eye field which sends signals to the contralateral paramedian pontine reticular formation (PPRF) for horizontal saccades and rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) for vertical saccades. The PPRF activates the ipsilateral abducens nucleus signaling the lateral rectus along with the contralateral medial rectus subnucleus of the oculomotor nucleus through the MLF. Convergence can be preserved in some cases of INO which can help distinguish this injury from pseudo-INO diseases (e.g. 3rd nerve palsy, myasthenia gravis).

Answer 21

Sagittal sinus thrombosis ## Footnote Clinical manifestations of homocystinuria include developmental delay, Marfanoid appearance, osteoporosis, ocular abnormalities, thromboembolic disease, and severe premature atherosclerosis.

Answer 22

Right Tuberculum Meningioma ## Footnote This patient has symptoms of direct right optic nerve compression, leading to painless, progressive vision loss and optic nerve pallor. Because she does not have light perception, she is does not have a pupillary response in that eye. She also has a left superior temporal visual field defect in the left eye likely due to compression on the inferomedial side of the left optic nerve or near the chiasm. Thus, she most likely has a tuberculum meningioma eccentric to the right or involving the right optic canal. Tumors in the occipital lobe would cause a contralateral homonymous hemianopsia. A trigeminal schwannoma, if large enough, might disrupt the optic radiations (Meyer’s loop) and cause a contralateral quadrantanopsia.

Answer 23

Surgical resection and whole brain radiation therapy ## Footnote The image depicts a right sided cerebellar lesion with significant mass effect to the adjacent brain parenchyma and compression on the Aqueduct of Sylvius. The patient’s history of colon cancer makes this likely to be a metastatic tumor. Level I evidence exists that for single brain metastases larger than 3 to 4 cm and amenable to safe complete resection, with favorable performance status and limited extracranial disease, surgery and whole brain radiation provides maximum local control and improvement of survival. Level I evidence demonstrates that surgery and whole brain radiation therapy is superior to WBRT alone in patients with single metastasis. Level III evidence indicates that surgery with stereotactic radiosurgery can provide survival benefit. Radiosurgery has been shown by Class I studies to extend survival in patients with metastatic brain tumors. In particular, radiosurgery with or without whole brain radiotherapy has been shown to extend survival 8-10.6 months (Aoyama et al). Routine use of chemotherapy following WBRT for brain metastases has not been shown to increase survival and is not recommended.

Answer 24

Conversion Reaction ## Footnote Without any funduscopic abnormalities, this is most likely conversion reaction or conversion disorder (CD) and none of the other pathologies listed which would have abnormal exam findings. Although the exact etiology or pathogenesis of CD is not known, CD is often found to be associated with recent psychological trauma, stressors, or conflicts Patients with non-organic disease may present to ophthalmologists with afferent (visual loss) or efferent (double vision) complaints. An ophthalmologist should carefully document the eye findings and if nonorganic disease is suspected careful attention to proving that the vision is better than claimed is essential for diagnosing nonorganic disease. A normal structural eye examination is not sufficient to make the diagnosis of nonorganic visual loss and formal visual field testing is recommended for patients with unexplained visual loss.

Answer 25

Temporal Lobe ## Footnote Homonymous superior quadrantanopia, also called “pie in the sky,” causes a field deficit in the superior field of both eyes for the same side. Temporal lobe surgery (surgery beyond 3 cm of the temporal lobe usually produces a superior quadrantanopsia, while surgery beyond 8 cm usually will produce complete homonymous hemianopia). Between 89%-91% of the patients have a deficit; those with selective amygdalohippocampectomy less pronounced than those with standard temporal lobectomy

Answer 26

Perioperative intravenous hydration ## Footnote Water and electrolyte homeostasis is of critical importance following transsphenoidal pituitary surgery. In the immediate postoperative phase, polyuria is most likely the result of intravenous hydration during surgery especially since the serum sodium is not elevated. Diabetes insipidus is characterized by excessive urinary output with a rise in serum sodium and osmolarity. Often times, patients have increased thirst and are able to maintain electrolyte homeostasis and fluid balance with increased free water consumption. When patient driven thirst is unable to maintain homeostasis, DDAVP should be administered to augment polyuria and hypernatremia. SIADH results in reduced free water excretion and a decrease in serum sodium and osmolarity. It may be seen as part of the triphasic response following pituitary surgery in which patients have an initial phase of DI, followed by SIADH, and then DI again. If DI is sustained, patients may need to be maintained on supplemental DDAVP in the outpatient setting. Cerebral salt wasting is a form of volume depletion associated with natriuresis; it is often associated with subarachnoid hemorrhage.

Answer 27

Isocitrate dehydrogenase (IDH) 1 mutation ## Footnote IDH1/2 mutations are associated with an improved overall survival in glioblastoma (27 versus 11 months approximately) and are found in younger patients. IDH mutations are also associated with secondary glioblastoma (progressed from lower grade gliomas). TERT promoter mutation is one of the criteria associated with a diagnosis of glioblastoma even if the tumor has no necrosis. ATRX mutations are common in glioblastoma. EGFRvIII amplication is found mostly in primary glioblastoma. CDKN2A deletion is associated with shortened survival in glioma patients.

Answer 28

ACTH secreting pituitary adenoma ## Footnote Cushing’s syndrome encompasses all forms of glucocorticoid excess, both iatrogenic and noniatrogenic. Cushing’s disease is the result of glucocorticoid excess in response to a ACTH secreting pituitary adenoma, and is the most common form of non-iatrogenic Cushing’s syndrome. Glucocorticoid excess presents with central obesity with supraclavicular fat accumulation, thinned skin, purple striae, proximal muscle weakness, osteoporosis, fatigue, hypertension, diabetes, acne, hirsutism, and dysmenorrhea. Iatrogenic Cushing’s syndrome most commonly occurs following prolonged steroid therapy (ie. Oral prednisone). Adrenocortical adenomas will produce cortisol independent of ACTH stimulation. Neuro-endocrine tumors (ie. Carcinoid or small cell lung cancer) may result in ectopic ACTH production and Cushing’s syndrome as a paraneoplastic syndrome. Pro-opiomelanocortin (POMC) is a precursor peptide synthesized in the anterior pituitary gland, from which it is cleaved to produce a few smaller peptides—one of which is ACTH. Overproduction of CRH from the hypothalamus is not the most common cause of non-iatrogenic Cushing’s syndrome.

Answer 29

Hemangioblastoma ## Footnote Hemangioblastoma, pilocytic astrocytoma, pleomorphic xanthoastrocytoma, and ganglioglioma all cause cysts with mural nodules but gangliogomas and PXAs are typically supratentorial so hemangioblastoma is the best answer. Medulloblastoma typically cause more heterogenous lesions, not cysts with mural nodules. Abscesses are usually ring enhancing without nodularity. Hemangioblastomas are characterized by neoplastic stromal cells with high vascularity and are commonly found in the cerebellum, brainstem or spinal cord. They are WHO grade I tumors and can be associated with von Hippel-Lindau (VHL) disease.

Answer 30

Enterovirus ## Footnote Acute flaccid paralysis (also referred to as acute flaccid myelitis) refers to a syndrome of acute paralysis in the setting of anterior myelitis that affects the spinal cord gray matter. Given its clinical parallels with polio-virus, the term “polio-like” syndrome has been historically used. Acute flaccid paralysis typically affects healthy children (median age ~7 years) following a febrile illness. The neurologic manifestations typically begin 5 days later. MR imaging typically demonstrates T2WI hyperintense lesions within the gray matter of the spinal cord without enhancement. Occasionally edema and cord expansion can be observed. There is not one single cause of acute flaccid paralysis, but an association between recent enterovirus (i.e. coxsackie viruses) infections and this condition have been postulated. Herpes Simplex Virus – Can cause an encephalitis, usually affecting the temporal lobes. Has not been associated with this condition. JC virus – virus that leads to progressive multifocal leukoencephalopathy in immunocompromised individuals Borrelia burgdorferi – Spirochete that causes Lyme’s Disease Group A beta-hemolytic streptococcus –Causative agent of pharyngitis that can subsequently lead to development of rheumatic fever and Sydenham’s Chorea

Answer 31

Paraganglioma ## Footnote Paragangliomas arise from paraganglion cells and are categorized based on their site of origin. The tumor resulting in the described findings are from the glomus jugulare, or the superior vagal ganglion. Glomus jugulare tumors present with dysfunction of cranial nerves IX, X, and XI, or XII. Paragangliomas in the temporal bone can present with pulsatile tinnitus. This may be associated with conductive hearing loss causing by tumor in the middle ear cavity. Cranial nerve palsies may include CV VII, IX, X, and XII. A conductive or mixed hearing loss associated with a pulsatile red mass behind the tympanic membrane, or a red mass arising from the hypotympanum, known as the ‘rising sun’ sign is a commonly seen clinical sign. Paragangliomas in the cervical region can present as a mass in the neck or a husky voice. Some may experience difficulties with swallowing, and be associated with deficits of CN IX, X, XI, or XII. Paragangliomas are known for having a “salt and pepper” speckled appearance. Meningiomas occurring within the jugular foramen are exceedingly rare lesions presumed to arise from arachnoid-lining cells situated within the jugular foramen. Meningiomas demonstrate more uniform enhancement on MRI with contrast. A dural tail may also be present. Schwannomas may occur in this region but would involved the nerves of the jugular foramen (IX, X or XI), not the vestibular nerve. These lesions are hypointense on T1 but enhance greatly with gadolinium, although not necessarily as brightly as meningiomas. Cholesterol granulomas cause a local bone erosion with smooth borders and having imaging characteristics of a fluid filled lesion. Metastatic lesions are usually lytic bone lesions and are more uniform in appearance.

Answer 32

Ophthalmic division ## Footnote Herpes Zoster of the trigeminal nerve has a predilection for the ophthalmic branch. Herpes zoster can also affect the facial nerve (Ramsay-Hunt syndrome).

Answer 33

Vitamin B3 (niacin) ## Footnote Vit B3 (niacin) deficiency = Pellagra (meaning "raw skin") is characterized by a photosensitive pigmented dermatitis (typically located in sun-exposed areas), diarrhea, and dementia. In the United States and other resource-rich countries, pellagra tends to occur in alcoholics and has been reported as a complication of bariatric surgery, anorexia nervosa, or malabsorptive disease

Answer 34

Lisch nodules ## Footnote This patient is presenting with brain tumor and subcutaneous nodules and hyperpigmented patches. The most likely syndrome that encompasses these findings together is Neurofibromatosis Type 1 (NF1). NF1 is a neurocutaneous disorder associated with unique neurologic and cutaneous findings. The diagnostic criteria for NF1 includes 2 or more of the following findings: ≥ 6 café au lait spots, ≥ 2 neurofibromas of any type, freckling in the axillary or intertriginous areas, ≥ 2 Lisch nodules, optic glioma, distinctive osseous abnormalities, or a first degree relative with NF1. In addition to optic gliomas, astrocytoma in other locations and meningioma can be found in NF1. Lisch nodules are pigmented iris hamartomas that appears as translucent yellow/brown elevations. They can be detected on ophthalmologic examination in a patient with NF1. Café au lait spots are hyperpigmented oval light brown macules found on the skin of NF1 patients. Visual field deficits can occur with space occupying lesion in the occipital lobe or compression on the optic chiasm. Parinaud’s syndrome is the inability of upward gaze, loss of pupillary reflex, and convergence nystagmus. These are associated with tumors in the pineal region but are not typically associated with subcutaneous lesions or skin pigmentation. Papilledema is a result of increase intracranial pressure and not necessarily associated with NF1.

Answer 35

24-Hour urinary free cortisol assay ## Footnote This is a patient the clinical features of Cushing’s syndrome. This occurs when the body has an excess of cortisol. Common symptoms include weight gain, moon facies, buffalo hump, abdominal striae, and thinned/fragile skin. Measurement of 24-hour urine free cortisol level is the preferred screening test for Cushing’s syndrome. In this patient, the MRI localizes a microadenoma. Therefore, there is no need for any further testing such as inferior petrosal sinus sampling. The treatment of choice is surgery, as complete resection results in chemical cure.

Answer 36

Transsphenoidal surgery for tumor resection ## Footnote Patient presents with a likely nonfunctioning pituitary macro-adenoma with vision loss consistent with chiasmatic compression. The most appropriate intervention would be tumor resection and decompression of the sellar via a transsphenoidal approach as opposed to interhemispheric approach. The mild elevation of prolactin is likely stalk effect as opposed to prolactinoma hence medical therapy would not be effective. Radiotherapy is not indicated in this setting of vision loss and chiasm compression. References:

Answer 37

Aseptic meningitis ## Footnote This posterior fossa tumor has a pearly-white appearance which is classic for an epidermoid. Resection of epidermoid cysts is associated with aseptic, or chemical meningitis. Bacterial meningitis, subtotal resection, and deep vein thrombosis are risks with any brain surgery but are much less common than aseptic meningitis for these patients. Akinetic mutism can rarely occur after posterior fossa surgery if a transvermian approach is taken to the fourth ventricle However, the operative image shows an infracerebellar telovelar approach is being used so akinetic mutism is unlikely.

Answer 38

Reassurance and follow-up MRI in 6 months ## Footnote Reassurance and follow-up MRI are most appropriate. Most vestibular schwannomas grow at a slow rate. In an elderly patient who demonstrates an intracanalicular acoustic neuroma, the tumor can be followed with serial MR imaging until there is demonstrable growth. If an acoustic neuroma progresses in an elderly patient, stereotactic radiosurgery can often times be employed to inactivate the tumor cells. Long-term control of growth in acoustic neuromas following radiosurgery is greater than 90%. Immediate resection either via a retrosigmoid or translabyrinthine approach in elderly patients can be associated with higher complication rates, and these risks would likely outweigh the benefits especially in the setting of this small of tumor.

Answer 39

Creutzfeldt–Jakob Disease ## Footnote Creutzfeldt–Jakob Disease is a rapidly, progressive, fatal spongiform encephalopathy that results from the pathologic accumulation of prions within the brain. Several forms of CJD have been described: Acquired, Familial, Sporadic and variant. The sporadic variant accounts for 85% of cases of CJD and typically occurs in the 7th decade of life. Sporadic CJD is thought to result from a somatic mutation in a cellular protein (MM1) that induces prion formation. Familial CJD accounts for approximately 10% of cases of CJD and is caused by familial mutations in PRNP (major prion protein PrP). Acquired CJD (usually through iatrogenic inoculation of contaminated dural grafts or corneal transplants) is less common. Variant CJD (i.e. Bovine Spongiform Encephalopathy) occurs from the ingestion of contaminated foods with prions. In all cases, the accumulation of insoluble prions within the brain leads to microglial activation, neuronal loss and neurodegeneration leading to spongiform changes on pathologic analysis. Patients typically exhibit progressive dementia of unknown origin as well as myoclonus, ataxia, or akinetic mutism. The WHO has diagnostic criteria for CJD that include: Rapidly progressive dementia + 2 or more of: Myoclonus, visual/cerebellar signs, Pyramidal/Extrapyramidal signs, Akinetic mutism + At least one of: Periodic Sharps Waves On EEG; Positive 14-3-3 CSF assay in patients with disease for 2 or more years It is important to recognize that the periodic sharp waves on EEG can fluctuate during the disease course and during sleep/wake cycles. Their presence has a 95% PPV. The gold standard of diagnosis remains brain biopsy although this may not be necessary in all situations. Herpes Encephalitis – Typically will present with fever, headaches, seizures and altered mental status. EEG may show evidence of PLEDs. Bilateral PLEDs are almost diagnostic of HSE Subacute Sclerosis Panencephalitis – This is a progressive encephalitis, usually of children and young adults. Usually follows diagnosis of measles earlier in life. EEG findings usually include periodic high voltage with 4-14ms separation with body jerks Hepatic Encephalopathy – Occurs in liver failure, EEG will show non-specific triphasic waves ALS - Caused by degeneration of anterior horn cells and corticospinal tracts leading to mixed upper and lower motor neuron findings, typically will have progressive muscle wasting, weakness, fasciculation but no cognitive changes.

Answer 40

Von Hippel-Lindau disease ## Footnote This patient has an enhancing tumor of her posterior fossa. Von Hippel-Lindau disease is associated with hemangioblastomas which are typically cystic tumors of the posterior fossa with an enhancing nodule. VHL results from a germline mutation in the VHL tumor suppressor gene on chromosome 3 and is an autosomal dominant condition. Patients may also have retinal hemangioblastoma, head/neck paragangliomas, renal cell carcinoma or cysts, pheochromocytoma, pancreatic cysts, endolymphatic sac tumors of the inner ear, papillary cystadenomas of the epididymis and broad ligament cystadnomas. Turcot syndrome can be associated with glioblastoma or medulloblastoma, but this tumor does not appear heterogenous as one would expect for glioblastoma or medulloblastoma. Neurofibromatosis type 2 is associated with schwannomas and meningiomas which are extraaxial tumors. Cowden disease is associated with Lhermitte-Duclos which is a dysplastic gangliocytoma of the cerebellum which is bright on T2 but usually does no enhance. Tuberous sclerosis causes subependymal giant cell astrocytoms and hamartomas. SEGAs are typically intraventricular and hamartomas do not enhance.

Answer 41

Hydrocortisone ## Footnote The patient described her has a large pituitary adenoma with low serum cortisol and low free thyroxine. He should be administered glucocorticoid replacement therapy prior to undergoing surgery in order not to precipitate an Addisonian crisis. This is a potentially life threatening emergency of acute adrenal insufficiency. It is characterized by rapid progression of nonspecific symptoms: fatigue, weakness, nausea, vomiting, abdominal pain, back pain, diarrhea to hypotension, syncope, obtundation, encephalopathy, and shock. This is differentiated from Addison’s disease which is a chronic state of cortisol deficiency due to primary adrenal insufficiency. A large non-secreting adenoma may result in local mass effect on hypophyseal portal vessels, resulting in a deficiency of normal hormone release. This explains the low cortisol and thyroxine levels (decreased ACTH and TSH release) observed in this scenario. Levothyroxine should not be administered before steroid therapy, as this can also precipitate an Addisonian crisis.

Answer 42

Left Internal Carotid Artery ## Footnote The image demonstrates the surgical view from a right orbitofrontal craniotomy. The craniopharyngioma can be seen between the optic nerves. On the ipsilateral side, the optic nerve can be seen just medial to the internal carotid artery. Just inferior to the contralateral optic nerve, the asterisk is marking the contralateral internal carotid artery. The anterior cerebral arteries would be just under the retractor. The pituitary stalk and gland are obscured by the mass itself which is filling the sella. The oculomotor nerve is not visible in this photo.

Answer 43

Cholelithiasis ## Footnote Octreotide is a somatostatin analog used in the treatment of acromegaly and thyrotrophinomas, management of carcinoid syndrome, diarrhea in patients with vasoactive intestinal peptidesecreting tumors, acute hemorrhage from esophageal varices, and management of gastrointestinal fistulas. It is administered subcutaneously or intravenously. The most common adverse events are gastrointestinal (34-61%) which can include cholelithiasis and decreased gallbladder motility, bradycardia (25%), conduction abnormalities (10%), arrhythmia (9%), hypoglycemia (3%), hyperglycemia (16%), hypothyroidism (12%), itching (18%), and other side effects. Cardiac valvular abnormalities may be seen with high doses of cabergoline during the treatment of prolactinomas.

Answer 44

Trochlear nerve ## Footnote Trochlear nerve palsies most commonly occur from congenital (49%), hypertensive (18%), and traumatic (18%). Other causes can include iatrogenic, idiopathic, neoplasm, diabetes, vascular insults, or from post-operative Herpes Zoster. Patients present with vertical or torsional diplopia that may worsen or improve in certain gazes. For a right superior oblique palsy, the diplopia is worsened with downward and inward (esotropic) gaze. This often makes it difficult for patients with trochlear nerve palsies to walk down stairs. Patients may compensate by adopting a head tilt and face turn to the opposite side, which in this case would be towards the left. Various techniques for detecting a trochlear nerve palsy can include the Maddox Rod test, Parks three-step test,Bielschowsky head tilt test, or red-green colored glasses.

Answer 45

Increased serum osmolarity, decreased urine osmolarity ## Footnote The patient in this scenario has developed central diabetes insipidus (DI) due to injury to the infundibulum or posterior pituitary. This results in inadequate release of arginine vasopressin from the posterior pituitary leading to an inability to conserve free water in the kidneys. This leads to the excretion of large volumes of dilute urine independent of the bodies hydration status. If the patient is unable to maintain homeostasis, this can lead to severe hydration and electrolyte derangement—a potentially fatal event. These patients should be monitored with strict intake and outputs and frequent sodium checks. Supplementary DDAVP should be administered if the patient is unable to maintain homeostasis via voluntary oral free water consumption. DI results in an increase in serum osmolarity with a decrease in urine osmolarity.

Answer 46

Sydenham’s Chorea ## Footnote Sydenham’s chorea is the most prevalent form of chorea in children and is one of the criteria for the diagnosis of rheumatic fever. Patients with Sydenham’s chorea are usually children and they typically develop involuntary movements of the face, arms and hands several weeks after Group A beta-hemolytic streptococcal infection of the pharynx. This patient had a recent pharyngitis followed by the development of chorea-like symptoms. Thus, the most likely diagnosis for this patient is Sydenham’s chorea. Huntington’s disease (HD) is a hereditary choreiform disorder that leads to chorea and eventually dementia. HD is often inherited in an autosomal dominant (trinucleotide repeat disorder of the HTT gene) fashion, although spontaneous cases can develop as well. HD demonstrates anticipation, therefore the age of onset of the disorder tends to occur at earlier ages in successive generations. Most cases of spontaneous HD and inherited HD occur between 30-45 years of age. Given that this patient has no dementia, a recent pharyngitis and no family history of neurologic diseases, Huntington’s disease is not the most likely diagnosis. Wilson’s Disease (also known as hepatolenticular degeneration) is a copper storage disease that leads to pathologic accumulation of copper in the liver, brain and cornea as well as other organs. Copper deposition in the brain typically occurs in the putamen but can also be present in the midbrain and thalamus. Patients with Wilson’s disease can develop progressive choreiform movements. In the absence of a history of liver dysfunction and given that Wilson’s disease is extremely rare, this is not the most likely diagnosis. Chorea-acanthocytosis is a very rare disorder that affects leads to abnormal red blood cell development (acanthocystosis) as well as muscle atrophy. Patients can develop chorea involving the trunk and limbs in addition to seizures and muscle wasting. Chorea gravidum is a non-specific description of chorea that occurs during pregnancy. The causes are likely multifactorial and in many original reports of Chorea gravidum were likely cases of Huntington’s disease or Sydenham’s Chorea that occurred during pregnancy. This patient is not pregnant and other options are more likely.

Answer 47

## Footnote Deficiency in vitamin B12 (cobalamin) can lead to subacute combined degeneration, resulting in degeneration of the dorsal and lateral white matter of the spinal cord and myelopathy, producing a slowly progressive weakness, sensory ataxia, and paresthesias, and ultimately spasticity, paraplegia, and incontinence. Vitamin A deficiency, Vitamin D deficiency, thiamine deficiency, and niacin deficiency are not associated with myelopathy.

Answer 48

Episodic unilateral diplopia, Eye pain, Ptosis, pupillary dilation ## Footnote Tolosa-Hunt syndrome (THS) is a painful ophthalmoplegia caused by nonspecific inflammation of the cavernous sinus or superior orbital fissure. It is characterized as episodic orbital pain associated with paralysis of one or more of the third, fourth, and/or sixth cranial nerves, which usually resolves spontaneously but tends to relapse and remit. It responds well to steroids for treatment.

Answer 49

Trigemino-cardiac reflex ## Footnote The figure demonstrates an enhancing right sided cerebellopontine angle lesion with extension into the right internal acoustic canal. Along with the patient’s auditory and vestibular symptoms, this lesion is consistent with a vestibular schwannoma. The reflex ilicited is the trigemino-cardiac reflex (TCR). The TCR is a sudden onset of parasympathetic dysrhythmias including hemodynamic irregularities, apnea, and gastric hypermotility during stimulation of the sensory branches of the trigeminal nerve. The afferent limb is the trigeminal nerve, with the vagus nerve as the efferent limb. The TCR has been found to occur during craniofacial surgery, balloon-compression rhizolysis of the trigeminal ganglion, and tumor resection in the cerebellopontine angle, cavernous sinus, and the sella. The glossopharnygel-vagal reflex is bradycardia and asystole from irritation to the glossopharyngeal nerve. The oculocardiac reflex is moderate trigemino-vagal bradycardia that is elicited by tenson on an extraocular muscle. The vaso-vagal response is arteriolar dilation and cardiac slowing secondary blood loss or emotional stress. The Cushing reflex results in increased blood pressure, irregular breathing, and bradycardia, and is a response to increased intracranial pressure.

Answer 50

Liver ## Footnote Acromegaly is a rare tumor, most commonly the result of a growth hormone (GH) secreting pituitary adenoma. Excess GH acts on the liver leading to overproduction of IGF-1. Clinically, it presents as excessive growth of hands and feet, soft tissue swelling, arthralgias, jaw prognathism, hyperglycemia, dysmenorrhea, erectile dysfunction, facial (prominence of the brow and macroglossia) and skeletal disfigurement (gigantism), osteoarthritis, hypertension, and respiratory and cardiac failure.

Answer 51

Germinoma ## Footnote This patient's imaging findings are most consistent with a germinoma, which typically appears as a solid contrast enhancing mass on CT/MR in the pineal region (and/or the hypothalamic region). Furthermore, germinomas are often described as engulfing the pineal gland, which gives the appearance of central calcification. The differential diagnosis of pineal region masses includes Germ Cell Tumors (~75% of all pediatric cases), Pineal Parenchymal Tumor (~25% of all pediatric cases), PNET, or Glioma. Germinoma is the most common (~50%) of the germ cell tumors. Unlike most CNS tumors, germ cell tumors may be associated with elevations in CSF levels of alpha-Fetal Protein (aFP), betahuman-Chorionic Gonadotropin (bhCG), and placental-like alkaline phosphatase (PLAP). Germinoma is associated with increased PLAP, and possible changes in bhCG. Large increases in bhCG are seen with choriocarcinoma, and elevations of aFP are seen with yolk-sac (endodermal sinus) tumor. Pilocytic astrocytomas. Ependymomas, and medulloblastomas are brain tumors that present in the pediatric population, but are not commonly located in the pineal region.

Answer 52

Grade I ## Footnote The Simpson grading scale was developed in 1957 by Donald Simpson. It is the gold standard for defining the surgical extent of resection of WHO grade I meningiomas. The grading system was developed primarily to predict recurrence based on the extent of tumor resection. Recent reports have challenged the applicability of the scale to the modern approach to meningiomas. Grade I is defined by a complete macroscopic resection of the tumor with removal of affected bone and dura. Grade II is complete macroscopic resection of the tumor with coagulation of the affected dura. Grade III is complete macroscopic resection of the tumor only. Grade IV is subtotal tumor resection. Grade V is decompression of the tumor with or without a biopsy.

Answer 53

Family history of NF2 and 2 additional lesion types (e.g., meningioma, glioma, etc.) ## Footnote Various diagnostic criteria for neurofibromatosis 2 (NF2) exist and are currently evolving. NF2 is defined by four clinical criteria: 1) bilateral vestibular schwannomas; 2) a family history of NF2 AND unilateral vestibular schwannoma OR any 2 associated lesions; 3) unilateral vestibular schwannoma AND any 2 of the following lesion types; 4) multiple meningiomas AND unilateral vestibular schwannoma OR any 2 NF2-associated lesion. The NF2-assocaited lesions are meningioma, glioma, schwannoma, juvenile posterior subcapsular lenticular opacity, or juvenile cortical cataracts.

Answer 54

Retinal angioma ## Footnote Von Hippel Lindau (VHL) disease results from VHL mutation and is associated with hemangioblastomas of the brain, spinal cord and retina; renal cysts and clear cell renal cell carcinoma; pheochromocytoma, pancreatic cysts, and neuroendocrine tumors; endolymphatic sac tumors; and epididymal and broad ligament cysts. Renal cell carcinoma occurs in about 70% of individuals with VHL and is the leading cause of mortality. Cutaneous manifestations in VHL are rare. The vast majority of cerebellar hemangioblastomas are sporadic with about 20% related to familial VHL. Standardized guidelines govern the screening, genetic testing and surveillance of patients with VHL syndrome.

Answer 55

Petrosal sinus sampling ## Footnote Petrosal sinus sampling allows for measurement of ACTH in the petrosal sinus and the peripheral blood at the same time. If the ACTH is elevated in the petrosal sinus, this would implicate a microadenoma in the pituitary gland as the source of elevated ACTH. This should only be performed once Cushing’s syndrome is confirmed with a urinary or salivary cortisol test or dexamethasone suppression test. The 24 hour urinary cortisol test and midnight salivary cortisol test determine if a patient has Cushing’s syndrome. Patients with an ACTH secreting pituitary microadenoma will often have cortisol suppression with a low dose dexamethasone suppression test while those with an ectopic source of ACTH will not have cortisol suppression with the low dose test.

Answer 56

Clinical observation ## Footnote Neurofibromatosis type 1 (NF1) is clinically defined by the presence of two or more of the following (Arch Neurol 1988;45:575-578): 1) 6 or more café-au-laut macules over 5 mm in diameter in prepubertal individuals and over 15mm in greatest diameter in postpubertal individuals; 2) Two or more neurofibromas of any type or one plexiform neurofibroma; 3) Freckling in the axillary or inguinal regions; 4) Two or more Lisch nodules (iris hamartomas); 5) Optic glioma; 6) A distinctive osseous lesion such as sphenoid dysplasia or thinning of long bone cortex, with or without pseudarthrosis; 7) First-degree relative (parent, sibling, or offspring) with NF-1 by the above criteria. Genetic testing can also be diagnostic. Patients with NF1 can present with brainstem gliomas however in many cases these can be observed and only treated if they become symptomatic. A series of 133 patients with NF1 at 4 major U.S. centers showed that the majority (54%) were asymptomatic at presentation and most were untreated (88%). Only 9 of 72 asymptomatic patients received treatment due to tumor enlargement. In contrast, 61 patients presented with focal neurological deficits and underwent treatment. These were more likely to be older children and those with focal lesions. Progression free survival was about 3 years shorter for the treated group. Overall survival was 85% for the tumor treated group and 100% for the untreated group.

Answer 57

Metastasis outside the CNS ## Footnote The MRI demonstrates a well circumscribed lesion with homogenous enhancement. The pathology findings , particularly the ‘staghorn’ vasculature, indicate the diagnosis of hemangiopericytoma. The most common associated clinical development of hemangiopericytoma is metastasis outside the CNS. Hemangiopericytoma is a rare, aggressive central nervous system tumor that tends to invade locally and metastasize, and has a high rate of recurrence. 20-50% metastasize to lungs, liver, or bone. On histopathology, tumors are uniformly cellular (similar to cellular areas of solitary fibrous tumor) with numerous, variably ectatic or compressed, thin-walled branching vessels with gaping sinusoidal spaces (staghorn configuration). Tumor cells are spindled to round with small amounts of pale or eosinophilic cytoplasm, indistinct margins, bland vesicular nuclei. Reported 5-year overall survival is 86%. Pheochromocytoma are associated with MEN-2 syndrome and glomus jugularae tumors. Bilateral vestibular schwannomas are associated with neurofibromatosis-2 (NF-2).Hemangiopericytoma are rarely associated with NF-2. Unilateral optic nerve glioma is associated with neurofibromatosis-1. De novo glioblastoma are not associated with hemangiopericytomas.

Answer 58

Late night salivary cortisol ## Footnote Recommended first line tests for the diagnosis of endogenous Cushing’s syndrome include urine free cortisol (at least two measurements), late night salivary cortisol (two measurements), and the the dexamethasone suppression test. Of these, late night salivary cortisol testing is the only correct answer choice listed. The insulin tolerance test and random serum ACTH or cortisol levels are not recommended tests for Cushing’s syndrome. A thorough history must be obtained to rule out an exogenous source of Cushing syndrome (ie. Chronic oral steroid therapy). Petrosal sinus sampling may help differentiate hypercortisolism from the pituitary vs. an ectopic origin, but is not the appropriate answer for the initial diagnosis of Cushing’s syndrome.

Answer 59

Transsphenoidal resection of the tumor ## Footnote Initial treatment of pituitary adenomas that are not prolactinomas is surgical resection, especially if causing visual symptoms. Prolactin levels can vary throughout the day and with a woman’s menstrual cycle. The upper limit of normal can vary depending on the laboratory, between 18-27 ng/ml. The heterogeneity of the hormone can also produce variable results between assays. Prolactinomas typically present with a serum prolactin level greater than 200ng/ml. Prolactin may be elevated in the absence of a prolactin-secreting adenoma secondary to drugs (phenothiazines, certain birth control pills), primary hypothyroidism, or "stalk effect". Stalk effect can occur in the setting of displacement or injury to the hypothalamus or pituitary stalk, with resultant decrease in prolactin inhibitory factor release. Prolactin elevations less than 150 ng/ml are generally not secondary to prolactinomas. Treatment of prolactinomas is typically administration of a dopamine agonist such as cabergoline. If medical therapy fails, then surgical resection should be considered. Somatostatin analogs, e.g. octreotide, can be used to treat growth hormone secreting adenomas.

Answer 60

Herpes simplex encephalitis ## Footnote The presentation of profound memory loss, mild nuchal rigidity, fever and LP findings of lymphocytosis should raise suspicion for viral meningitis. The memory loss symptoms suggest mesial temporal involvement. That in combination with mild xanthochromia on LP will favor Herpes Simplex meningitis. Aneurysmal SAH will be associated with headaches but not fever and CSF lymphocytosis. Brain abscess if evident on LP would be more consistent with a bacterial as opposed to viral meningitis. Primary CNS lymphoma except for the fever and meningismus. Hence the nest answer is herpes simplex encephalitis.

Answer 61

Biphasic pattern ## Footnote Juvenile pilocytic astrocytoms are WHO grade I tumors with a favorable prognosis. The most common histologic feature is a bisphasic pattern of bipolar cells and Rosenthal fibers mixed with areas of multipolar cells and eosinophilic granular bodies. Rosenthal fibers are often present in pilocytic astrocytoma but they are not required, nor are eosinophilic granular bodies. Additionally, neither of these findings is specific for pilocytic astrocytoma. Mitoses, necrosis and vascular proliferation can be present although these features are less common.

Answer 62

Carbergoline administration ## Footnote The patient described here has a prolactinoma. Prolactinomas are the most common types of pituitary micro- and macroadenomas and result in the secretion of excess prolactin. Large prolactinomas may exert local mass effect and cause cranial neuropathies. Prolactinomas may also cause endocrinopathies manifesting as osteoporosis, amenorrhea, decreased libido, galactorrhea, decreased fertility, and erectile dysfunction. Prolactin secretion is normally negatively related by dopamine that is produced and secreted by the hypothalamus. For non prolactin secreting adenomas, serum prolactin levels may be elevated due to mass effect on the infundibular stalk (disinhibiting the effect of dopamine on prolactin secretion). If serum prolactin level is in excess of 200 μg/mL, this is almost always due to a prolactin secreting tumor—rather than due to stalk effect. Primary treatment involves the administration of a dopamine agonist. Carbergoline is preferred over bromocriptine as it is better tolerated with a more favorable side effect profile. Carbergoline treatment is effective at reducing excessive prolactin secretion and normalization of prolactinoma size.

Answer 63

Toxoplasmosis ## Footnote The presentations of multiple intracranial calcifications, psychomotor retardation, seizures and retinal abnormalities are most likely consistent with toxoplasmosis infection. With Sturge Weber, we see intracranial calcifications, seizures, developmental delay and choroid abnormalities as well. However, a facial cutaneous angioma (port wine stain) along the trigeminal distribution is pathognomonic for Sturge Weber. Infantile spams are febrile seizures in isolation. Besides retinal abnormalities, retinoblastoma is not associated with any of the above findings. Anoxic brain injury can lead to psychomotor retardation and seizures but not typically retinal abnormalities or intracranial calcifications.

Answer 64

Middle Fossa approach ## Footnote The middle fossa approach allows for greater chance of hearing preservation for small vestibular schwannomas located distally in the internal auditory canal. This approach has been found to have a lower rate of hearing loss compared to the retrosigmoid approach. For larger tumors with and those with a large portion of tumor in the medial internal auditory canal or the cerebellopontine angle, the retrosigmoid approach allows for a higher chance of hearing preservation due to the limited field of view of the posterior fossa in the middle fossa approach. The translabyrnthine approach does not preserve hearing function but allows for removal of vestribular schwannomas of almost any size with early identification of the facial nerve. The pterional and the telovelar approaches do not provide access to vestibular schwannomas.

Answer 65

Renal failure ## Footnote A multitude of metabolic disorders are linked to myoclonus, including the following: Hyperthyroidism Hepatic failure Renal failure Dialysis syndrome Hyponatremia Hypocalcemia Hypomagnesemia Hypoglycemia Nonketotic hyperglycemia Multiple carboxylase deficiency Biotin deficiency Hypoxia Metabolic alkalosis Vitamin E deficiency Hypokalemia, metabolic acidosis, Vitamin A deficiency, and hypothyroidism are typically not associated with myoclonus.

Answer 66

Transsphenoidal or transcranial resection/decompression of the sellar ## Footnote The presentation of acute blindness in the setting of hemorrhagic infarction of known pituitary tumor is consistent with pituitary apoplexy. This is a neurosurgical emergency since restoration of vision is a key goal. The most appropriate intervention would be sellar decompression. In addition, medical management for cortisol and thyroid supplementation is important.

Answer 67

Vestibular schwannoma ## Footnote The three most common cerebellopontine angle lesions are vestibular schwannoma, meningioma, and epidermoid cyst. Imaging features of vestibular schwannomas and meningiomas will show enhancing lesions with various degrees of brainstem or cerebellar compression depending on the tumor size. Vestibular schwannomas will arise from the internal acoustic meatus while meningiomas will often have an associated dural tail or thickening. Facial nerve schwannomas can also present within the internal acoustic canal but are associated with early facial weakness due to compression of the facial nerve. Epidermoids are characterized by restricted diffusion on DWI-type MR images.

Answer 68

Choana ## Footnote The sphenoid sinus can be approached through various surgical techniques which include transseptal, trans-nasal, and intracranial skull base approaches. The endoscopic endonasal approach has become the most popular to address sellar lesions. The sphenoid ostium is a natural landmark for gaining access to the sphenoid sinus. It is generally about 1.5cm superior to the choana, although this can vary based on individual anatomy.

Answer 69

Location B ## Footnote This image shows a craniotomy with a mastoidectomy. The mastoid was where the “D” is located. Just below the “D” is the sigmoid sinus and between “B” and “E” is the transverse sinus. The superior petrosal sinus is just to the right of “A”. The vein of Labbe typically drains into the transverse sinus although it can drain into the superior petrosal sinus. This area is most closely approximated by “B”. Care must be taken to preserve the drainage of Labbe to prevent venous infarction.

Answer 70

Macrocytic anemia ## Footnote Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism and is a cofactor in DNA synthesis. The average recommended amount for an adult is 2.4 mcg per day. The classic findings associated with vitamin B12 and folate deficiency include worsening macrocytic anemia, yellow skin (caused by combined anemia and jaundice), and variable neurologic abnormalities more prominent in vitamin B12 deficiency (cognitive slowing and neuropathy).

Answer 71

Facial Nerve ## Footnote Lyme’s disease occurs as a result of a spirochetal infection (Borrelia burgdorferi) that is transmitted to humans by Ixodes species of ticks. There are three classic stages of infection of Lyme’s disease: Localized Stage I (localized, early infection, usually within days to weeks of infection), Disseminated Stage 2 (Disseminated early infection, usually within several weeks of infection) and Persistent Stage 3 (Late infection, occurs months after infection). Stage I disease includes the classic “Bull’s Eye Rash” (Erythema Migrans) and regional lymphadenopathy. Fever malaise, fatigue occur during the Stage 2 disease and occur as a result of hematologic dissemination of the B. burgdorferi. Approximately 15% of patients with Stage 2 Lyme disease will develop neurologic sequelae including motor/sensory radiculoneuritis, meningitis and classically cranial nerve palsies, the most common of which is a unilateral or bilateral facial palsy. Cerebellar ataxia, pseudotumor and myelitis have been described in patients with stage 2 disease. Neurologic symptoms can also occur in Stage 3 Lyme’s (encephalomyelitis, chronical axonal polyradiculopathy, and spastic paraparesis). Patients with facial palsy in the setting of Lyme’s disease are typically treated with 14-21 days of oral doxycycline. In patients with more advanced CNS infections (meningitis, radiculopathy), patients are typically treated with 14-28 days of intravenous ceftriaxone.

Answer 72

Facial Nerve ## Footnote Lyme’s disease occurs as a result of a spirochetal infection (Borrelia burgdorferi ) that is transmitted to humans by Ixodes species of ticks. There are three classic stages of infection of Lyme’s disease: Localized Stage I (localized, early infection, usually within days to weeks of infection), Disseminated Stage 2 (Disseminated early infection, usually within several weeks of infection) and Persistent Stage 3 (Late infection, occurs months after infection). Stage I disease includes the classic “Bull’s Eye Rash” (Erythema Migrans) and regional lymphadenopathy. Fever malaise, fatigue occur during the Stage 2 disease and occur as a result of hematologic dissemination of the B. burgdorferi. Approximately 15% of patients with Stage 2 Lyme disease will develop neurologic sequelae including motor/sensory radiculoneuritis, meningitis and classically cranial nerve palsies, the most common of which is a unilateral or bilateral facial palsy. Cerebellar ataxia, pseudotumor and myelitis have been described in patients with stage 2 disease. Neurologic symptoms can also occur in Stage 3 Lyme’s (encephalomyelitis, chronical axonal polyradiculopathy, and spastic paraperesis). Patients with facial palsy in the setting of Lyme’s disease are typically treated with 14-21 days of oral doxycycline. In patients with more advanced CNS infections (meningitis, radixulopathy), patients are typically treated with 14-28 days of intravenous ceftriaxone.

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