Chap 27 Morphology

Question 1

What are the characteristics of a schwannoma?

Answer 1

• Well-circumscribed, encapsulated mass that is next to it’s associated nerve without invading it
• Firm, gray mass
• associated with Schwannomas

Question 2

What does a schwannoma look microscopically?

Answer 2

Admixture of dense and lose areas known as Antoni A and Antino B
*associated with Schwannomas

Question 3

What are the characteristics of Antoni A?

Answer 3

Dense eosinophilic area that contains spindle cells arranged into cellular intersecting fascicles
*associated with Schwannomas

Question 4

Verocay bodies

Answer 4

Palisading of nuclei and “nuclear free zone” between regions of nuclear palisading
*associated with Schwannomas

Question 5

What are the characteristics of Antoni B?

Answer 5

Areas of spindle cells that are spread apart by myxoid extracelullar matrix
*associated with Schwannomas

Question 6

What do Schwann cells look like?

Answer 6

Spindled elongated nucleus with a wavy or buckled shape

*associated with Schwannomas

Question 7

Electron microscopy of a Schwann cell

Answer 7

Basement membrane deposits encasing single cells and collagen fibers
*associated with Schwannomas

Question 8

What are degenerative characteristics of Schwannomas?

Answer 8

Nuclear pleoorphism, xanthomatous change, vascular hyalinization, cystic change, necrosis and mitotic activity

Question 9

What are the characteristics of Localized Cutaneous Neurofibromas?

Answer 9

• Small, well delineated, nonencapsulated nodular lesions

- Located in the dermis and subcutaneous fat

Question 10

What are the contents of a localized cutaneous neurofibroma?

Answer 10

Bland Schwann cells mixed with stomal cells (mast cells, perineurial cells, CD34+ spindle cells, and fibroblasts)

Question 11

What does the stoma of a localized cutaneous neurofibroma contain?

Answer 11

Loose collagen

Question 12

What are the characteristics of a diffuse neurofibroma?

Answer 12

Distinct feature- infiltrated the dermis and subcutaneous connective tissue, entrapping fat and appendage structures
- Creates a plaque like appearance

Question 13

Pseudo-Meissner corpuscles/Tactile-like bodies

Answer 13

Focal collections of cells mimicking appearance of Meissner corpuscles
*associated with diffuse neurofibroma

Question 14

What are the characteristics of plexiform neurofibromas?

Answer 14

• Grow within and expand nerve fascicles which entraps the associated axons
• Individual nodule and encapsulated appearance
• Ropy thickening of multiple nerve fascicles causing “bag of worms” appearance

Question 15

Bag of worms appearance

Answer 15

ropy thickening of multiple nerve facicles

*associated with plexiform neurofibromas

Question 16

What is the collagen appearance in plexiform neurofibromas?

Answer 16

Seen in bundles linked to “shredded carrot”

Question 17

What is the morphology of malignant peripheral nerve sheath tumors?

Answer 17

• Poorly defined masses, infiltrate along the axis of the parent nerve and invade adjacent soft tissues

Question 18

What is the most common appearance of a malignant peripheral nerve sheath tumor?

Answer 18

• Fasciculated arrangement of spindle cells

- “Marbleized”

Question 19

What is “divergent differentiation”?

Answer 19

• *Seen in malignant peripheral sheath tumors
• Presence of focal areas that exhibit other lines of differentiation such as glandular, cartilaginous, osseous or rhabdomyoblastic morphology

Question 20

What is a Triton tumor?

Answer 20

A malignant peripheral sheath tumor that has focal areas with rhabdomyoblastic morphology