Neuro tumors

Question 1

Characteristics of astrocytoma

Answer 1

Originates from atrocytes

Immunoreactivity for glial fibrillary acidic protein (GFAP) and diffuse (ill-demarcated) pattern of growth

Pilocytic astrocytoma is a well-differentiated, benign astrocytic tumor that arises throughout the neuroaxis; it is common in children and young adults

Sites of involvement include posterior fossa (cerebellum) and diencephalon

Question 2

Radiographical characteristics of astrocytoma

Answer 2

Most show cystic lesion with a mural nodule

Question 3

Histologically characteristics of astrocytoma

Answer 3

Shows spindly neoplastic astrocytes with long bipolar processes
Rosenthal fibers

Question 4

What are rosenthal fibers?

Answer 4

Thick, corkscrew-like eosinophilic structures that derive from hypertrophic processes of atrocytes

Question 5

Characteristics of fibrillary (diffuse) astrocytoma

Answer 5

Low grade tumor that arises in the cerebral hemisphere of young to middle-aged and the brainstem of children
IDH1 positive

Question 6

Characteristics of anaplastic astrocytoma

Answer 6

Cellular, pleomorphic and mitotically active

Question 7

Characteristics of glioblastoma

Answer 7

Most common CNS primary malignancy in adults

Question 8

Histological characteristics of gliomblastoma

Answer 8

Shows necrosis and/or vascular proliferation in addition to features seen in anaplastic astrocytoma

Question 9

Characteristics of glioblastoma multiforme

Answer 9

Tendency to cross midline by involving the corpus callosum (“butterfly glioma”)

Question 10

Characteristics of oligo dendroglioma

Answer 10

Occurs more often in adults than in children
Cortical location; may cause seizures
Slow-growing
Tumors with deletions of 1P or 19q respond well to therapy

Question 11

Histological characteristics of oligo dendroglioma

Answer 11

Perinuclear halos are a fixation artifact that is not seen on frozen section

Question 12

Characteristics of ependymoma

Answer 12

Located in the fourth ventricle in children, where it presents with obstructive hydrocephalus
In adults the spinal cord is the most common site
Multifocality in the spinal cord is associated with NF2

Question 13

Histological characteristics of ependymoma

Answer 13

Pseudorosettes are a helpful diagnostic feature on microscopic study

Question 14

Characteristics of embryonal (primitive) tumors

Answer 14

Group of small round cell tumors that occur predominantly in children
In the cerebellum they are called medulloblastoma
Most common malignant brain tumor in children

Question 15

Characteristics of schwannoma

Answer 15

Originates from schwann cells of cranial or spinal nerves
Most frequent location is on CN8 at the cerebellopontine angle (CPA)
Manifests characteristically with unilateral loss of hearing and tinnitus
Prognosis good after resection
S100 positive
NF1

Question 16

NF2 schwannoma

Answer 16

Bilateral acoustic schwannoma

Question 17

Histological characteristics of schwannoma

Answer 17

Has spindly cells arranged in hypercellular Antoni A areas; alternating hypocellular Antoni B areas
Verocray bodies

Question 18

What are verocay bodies?

Answer 18

Parallel rows of neoplastic Schwann cells

Question 19

Characteristics of meningioma

Answer 19

Originates from meningothelial cells of the arachnoid
Common in adults (F>M), rare in children
Dura based mass
Clinical features: Headache, seizures and neurological deficits
Abnormalities of chromosome 22 sometimes present
Multiple meningiomas occur in NF2 patients

Question 20

Histological characteristics of meningioma

Answer 20

Shows cellular whorls and psammoma bodies

Syncytial pattern is common

Question 21

Characteristics of craniopharyngioma

Answer 21

Arises from odotogenic epithelium within the suprasellar/diencephalic region
Most commonly affects children and young adults
Most common presenting symptoms: Headache, hypopituitarism, and visual field disturbances
Contains deposits of calcium
Benign but tends to recur after resection
Beta-catenin (CTNNBIc) gene mutations have been reported

Question 22

Histological characteristics of craniopharyngioma

Answer 22

Shows squamous cells

Question 23

Characteristics of lymphomas

Answer 23

Most common CNS tumor in the immunosuppressed
May be multiple
Don’t respond well to chemo

Question 24

Characteristics of germ cell layers

Answer 24

More common in children than adults

Question 25

Histological characteristics of germ cell tumors

Answer 25

Germinoma most common histologic type

Question 26

Characteristics of Sturge-Weber syndrome

Answer 26

Also known as Encephalotrigeminal angiomatosis Presentation: Facial angioma (Port-wine stain) in the V1 + V2 distribution of trigeminal nerve Leptomeningeal angioma, often same side as the port-wine stain ``` Associated conditions: Mental retardation Epileptic spam at infancy Early onset glaucoma Skull radiopacities ("Tram track" calcification) ```

Question 27

Characteristics of Charcot-Marie-Tooth disease

Answer 27

Also known as hereditary motor and sensory neuropathy (HMSN) Mutations in a peripheral myelin protein (PMP22) forms unstable myelin Distal symmetric sensorimotor polyneuropathy with atrophy of the calf muscles ("stork legs") and pes cavus deformity Nerve conduction studies: decrease impulse conduction velocity

Question 28

Histological characteristics of Charcot-Marie-Tooth disease

Answer 28

Nerve biopsy-segmental demylination and remyelination with onion bulb formation

Question 29

Characteristics of neurofibroma

Answer 29

Heterogenous in composition- Schwann cells are admitted with perineural-like cells, fibroblasts, mast cells and CD34+ spindle cells Solitary are not associated with NF1 Multiple are associated with NF1 Often young, 20-30

Question 30

Classifications of neurofibroma

Answer 30

Cutaneous or dermal Diffuse Plexiform

Question 31

Characteristics of cutaneous or dermal neurofibroma

Answer 31

Small nodular tumors of the skin and subcutaneous tissue, arising from small cutaneous nerves

Question 32

Characteristics of diffuse neurofibroma

Answer 32

present as large plaque-like elevation of skin

Question 33

Characteristics of plexiform neurofibroma

Answer 33

multiple nodular masses affecting nerve roots, plexuses or large nerves (appear as "bag of worms")

Question 34

Characteristics of malignant peripheral nerve sheath tumors (MPNST)

Answer 34

Mostly high grade tumors, but uncommon Can be sporadic tumors or NF1-associated tumors arising through malignant transformation of a plexiform neurofibroma Most commonly found on the extremities and trunk, and less often on the head and neck An interesting feature of MPNST is a "divergent differentiation" i.e. the presence of other lines of differentiation, including glandular, cartilaginous, osseous or rhabdomyoblastic morphology S100+

Question 35

Characteristics of conjunctival carcinoma

Answer 35

Keratinizing squamous cell carcinoma Develop from precancerous lesion (Bowden's disease-squamous cell carcinoma in situ) Often associated with human papillomavirus (HPV) types 16 and 18 Clinical presentation: Whitish, bulging thickening of the epithelium with an irregular surface

Question 36

Characteristics of uveal melanoma

Answer 36

Most common primary intra-ocular malignancy of adults Develops from choroidal melanocytes Common location" Choroid~18%, Ciliary body ~15%, Iris~5% Risk factors: Uveal nevus, light skin color, and light color of iris Clinic: Visual field defects, floaters, and/or photopsia due to tumor-related retineal detachment Fundoscopy: A pigmented lesion near temporal margin of the optic disk

Question 37

Histological characteristics of retinoblastoma

Answer 37

Clinical features: Leukocoria ("cat's eye pupil"); Strabismus Progressive loss of vision- due to tumor infiltration into the macula or vitreous body Sudden loss of vision- due to retineal detachment

Question 38

Histological characteristics of retinoblastoma

Answer 38

Small blue cells- round with hyperchromatic nuceli, scanty cytoplasm Rosettes and fleurette Necrosis; viable tumor around blood vessels Dystrophic calcification- characteristic

Question 39

Characteristics of tuberous scelerosis

Answer 39

Characterized by hamartomas (cortical tubers) Presentation: Seizure (infantile spasms) Mutation: TSC1 (encodes hamartin on chromosome 9) TSC2 (encodes tuberin on chromosome 16) Skin: Adenoma sebaceum (angiofibromas) Hypopigmented macule (ash leaf spot) Shagreen patches Visceral cysts: Liver, kidney, pancreas Retina- Retinal glial hamartomas Heart-Cardiac rhabdomyomas Renal-Renal angiomyolipomas