Chap 28 Morphology 4

Question 1

What are the characteristics of diffuse astrocytomas?

Answer 1

Poorly defined, gray infiltrative tumors that expand and invade the brain

Question 2

What is always present in a diffuse astrocytoma?

Answer 2

Infiltration beyond the outer margins

Question 3

What is the microscopic appearance of a diffuse astrocytoma?

Answer 3

• Greater cellular density than normal white matter
• Astrocytic processes
• Indistinct transition between neoplastic and normal tissue

Question 4

What are the characteristics of an anaplastic astrocytoma?

Answer 4

• More densely cellular
• Greater nuclear pleomorphism
• Mitotic figures present

Question 5

What is a gemistocytic astrocytoma?

Answer 5

A tumor where the predominant neoplastic astrocyte shows brightly eosinophilic cell body

Question 6

What is the histologic appearance of a glioblastoma?

Answer 6

• Similar to an anaplastic astrocytoma + necrosis and vascular endothelial cell proliferation

Question 7

What is pseudo-palisading?

Answer 7

A histologic pattern where the tumor cells collect along the edges of the necrotic regions

Question 8

What occurs with vascular cell proliferation in glioblastomas?

Answer 8

• Tuft of cells pile up and create a double layer of endothelial cells
• Forms a ball-like structure called a glomeruloid bodyt

Question 9

What is the relevance of VEGF in relation to vascular change in glioblastomas?

Answer 9

VEGF is produced by malignant astrocytes in response to hypoxia

Question 10

What is gliomatosis cerebri?

Answer 10

A diffuse glioma with extensive infiltration in the brain

*Considered a grade III/IV lesion

Question 11

What are the common characteristics of pilocytic astrocytomas?

Answer 11

Cystic and usually well circumscribed

Question 12

What cells are present in a pilocytic astrocytoma?

Answer 12

Bipolar cells with long, thin “hairlike” processes that form fibrillary meshworks

Question 13

What can be a characteristic finding for a pilocytic astrocytoma?

Answer 13

Rosenthal fibers and eosinophilic granular bodies

Question 14

What is a difference between diffuse fibrillary astrocytomas and pilocytic astrocytomas?

Answer 14

Pilocytic astrocytomas show limiting infiltration to the surrounding brain whereas diffuse filbrillary astrocytomas do show infiltration

Question 15

What is the appearance of oligodendrogliomas?

Answer 15

Well circumscribed, gelatinous, gray masses, cystic, focal hemorrhage, minimal mitotic activity and calcification

Question 16

What is the histology of the cells in an oligodendroglioma?

Answer 16

Cells with spherical nuclei containing finely granular chromatin surrounded by a clear halo of vacuolated cytoplasm

Question 17

What are the characteristics of an anaplastic oligodendroglioma?

Answer 17

High cell density, nuclear anaplasia, detectable mitotic activity, and necrosis

Question 18

What cells and cellular components are in ependymomas?

Answer 18

• Cells with regular, round to oval nuclei and abundant granular chromatin
• Dense fibrillary background
• Tumor cells that form rosettes or canals

Question 19

What are rosettes?

Answer 19

Gland-like round structures formed by tumor cells

*Found in ependymomas

Question 20

What are canals?

Answer 20

Elongated structures formed by tumor cells that resemble the embryologic ependymal canal
*Found in ependymomas

Question 21

When are perivascular pseudorosettes present?

Answer 21

When tumor cells are arranged around vessels with an intervening zone of thin ependymal processes directed toward the wall of the vessel

Question 22

What are the characteristics of an anaplastic ependymoma?

Answer 22

Increased cell density, high mitotic rates, areas of necrosis, and less ependymal differentiation

Question 23

What are myxopapillary ependymomas?

Answer 23

Lesions that occur in the filum terminale of spinal cord

Question 24

What are the characteristics of a myxopapillary ependymoma?

Answer 24

• Have cuboidal cells around papillary cores containing connective tissue and blood vessels
• Contain neutral and acidic mucopolysaccharides

Question 25

What is the difference in location of medulloblastomas in children vs adults?

Answer 25

Children: located in the midline of the cerebellum Adults: lateral locations of the cerebellum

Question 26

What is the appearance of a medullablastoma?

Answer 26

- Well circumscribed, gray, and friable | - Mitoses are abundant and markers of cellular proliferation are in high percentage

Question 27

Microscopic examination of medullablastomas

Answer 27

- Very densely cellular with sheets of anaplastic cells | - Single cells are hyperchromatic nuclei and elongated or crescent shaped

Question 28

What tumors are Homer-Wright rosettes found?

Answer 28

Medullablastomas and neuroblastomas

Question 29

What is the nodular desmoplastic variant in medullablastomas?

Answer 29

- Area of stomal response marked by collagen and reticulin deposition - Nodules forming "pale islands"

Question 30

What is the large cell variant in medullablastomas?

Answer 30

- Large irregular vesicular nuclei , prominent nucleoli, and frequent mitosis and apoptotic cells

Question 31

What is the term "drop metastases"?

Answer 31

When nodular masses form at distance from the primary tumor mainly from CSF dissemination

Question 32

Characteristics of atypical teratoid/rhabdoid tumor

Answer 32

Large, soft consistency, that spread along surface of the brain and have lots of mitotic activity

Question 33

What is the appearance of a rhabdoid cell?

Answer 33

- Eosinophilic cytoplasm - Sharp cell borders - Eccentrically located nuceli

Question 34

Characteristics of Primary CNS lymphoma lesions

Answer 34

Lesions are multiple and involve the deep gray matter, white matter, and cortex

Question 35

What is the most common histologic group of primary CNA lymphomas?

Answer 35

B-cell lymphomas

Question 36

What is the histologic pattern, "hooping", and when does it occur?

Answer 36

Hooping is when infiltrating cells are separated form one another by silver-staining material *Seen in primary brain lymphomas

Question 37

What marker is expressed in Primary CNS lymphomas?

Answer 37

B cell markers- CD20

Question 38

What is the appearance of a meningioma?

Answer 38

- Rounded mass with well-defined dural bases that compress underlying brain - Surface is encapsulated by fibrous tissue

Question 39

What is "en plaque" and when is it seen?

Answer 39

When the tumor spreads in a sheetlike fashion along the surface of the dura *Seen in meningiomas

Question 40

What is the histologic pattern, syncytial, and when is it present?

Answer 40

Whorled clusters of cells that sit in tight groups without visible cell membranes *Seen in meningiomas

Question 41

What is the histologic pattern, fibroblastic, and when is it present?

Answer 41

Elongated cells with abundant collagen deposition between them *Seen in meningiomas

Question 42

What is the histologic pattern, transitional, and when is it present?

Answer 42

Share features of syncytial and fibroblastic | *Seen in meningiomas

Question 43

What is the histologic pattern, psammomatous, and when is it present?

Answer 43

Psammona bodies that form from calcification of syncytial nests of meningothelial cells *Seen in meningiomas

Question 44

What is the histologic pattern, secretory, and when is it present?

Answer 44

PAS-positive intracytoplasmic droplets and intracellular lumens by electron microscopy *Seen in meningiomas

Question 45

What is the histologic pattern, microcystic, and when is it present?

Answer 45

Loose, spongy appearance and is associated with a specific genotype--> mutations in TRAF7 and KLF4 *Seen in meningiomas

Question 46

What is an atypical meningioma?

Answer 46

A lesion with a higher rate of recurrence and more aggressive local growth

Question 47

How are atypical meningiomas distinguished?

Answer 47

Have 4 or more mitoses per 10 power fields or at least 3 atypical features

Question 48

What are examples of atypical features?

Answer 48

Increased cellularity, small cells with high nuclear-to-cytoplasmic ratio, prominent nucleoli, patternless growth, or necrosis

Question 49

What is an anaplastic (malignant) meningioma?

Answer 49

Highly aggressive tumor with the appearance of a high-grade sarcoma but retain histologic evidence of meningioma origin

Question 50

Papillary Meningioma

Answer 50

Pleomorphic cells arranged around fibrovascular cores

Question 51

Rhabdoid Meningioma

Answer 51

Sheet of tumor cells with hyaline eosinophilic cytoplasm containing intermediate filaments

Question 52

Characteristics of intraparenchymal metastases

Answer 52

- Sharply demarcated - At the junction of gray and white matter - Surrounded by a zone of edema

Question 53

What metastatic tumor is associated with carcinoma of the lung and breast?

Answer 53

Meningeal carinomatosis

Question 54

Characteristics of cortical hamartomas of tuberous sclerosis

Answer 54

Firm areas of cortex that are comprised of haphazardly arranged neurons that lack organization

Question 55

What does "candle-guttering" mean and when is it seen?

Answer 55

- Droplike masses that bulge into the ventricular system | * Seen in tuberous sclerosis

Question 56

What are hemangioblastomas?

Answer 56

Highly vascular neoplasms that occur as a nodule and are associated with a large fluid-filled cyst

Question 57

What is considered the neoplastic element in hemangioblastomas and why?

Answer 57

Stromal cells that express inhibin- they are the neoplastic element because they show the presence of the second "hit" in the preciously normal VHL allele