Ch. 22 - Neural tumors

Question 1

Neurofibroma

Answer 1

Loose myxoid arrangement of haphazard spindle cells with small wavy nuclei.

Question 2

Diffuse neurofibroma

(differential?)

Answer 2

Diffuse replacement of dermis and fat with typical features of neurofibroma. Rule out DFSP (S100-).

Question 3

Plexiform neurofibroma

Answer 3

Large fascicles of neurofibroma surrounded by perineurium (“bag of worms”)

Question 4

Schwannoma (neurilemmoma)

Answer 4

Deep dermal tumors arising within nerve with perineural capsule. Antoni A tissue with parallel rows of nuclei separated by acellular Verocay bodies, Antoni B tissue degenerative with edematous stroma.

Question 5

Ancient schwannoma

Answer 5

Benign degenerative schwannoma with hyperchromatic pleomorphic nuclei.

Question 6

Neuromas

Answer 6

Nerve sheath tumors with a 1:1 ratio of axons to schwann cells.

Question 7

Traumatic neuroma

Answer 7

Multiple nerve fascicles embedded in a fibrous scar.

Question 8

Palisaded encapsulated neuroma

Answer 8

Superficial nonpalisading clefted fascicles with a thin, delicate capsule.

Question 9

Supernumerary digit (rudimentary polydactyly)

Answer 9

Acral papule with nerve bundles and sometimes bone or cartilage.

Question 10

Merkel cell carcinoma (primary neuroendocrine carcinoma of the skin, trabecular carcinoma)

IHC?

Answer 10

Small blue cells in sheets or trabeculae. Nuclear molding and atypia.

Synapto/chromo+, NSE+, CK20+ (paranuclear dot pattern)

Question 11

Granular cell tumor

Answer 11

Sheets of large polygonal cells with eosinophilic granules (pustulo-ovoid bodies of Milian) and overlying pseudoepitheliomatous hyperplasia.

Question 12

Myxoid neurothekeoma (nerve sheath myxoma)

Answer 12

Multiple myxoid lobules with sparse stellate cells.

Question 13

Cellular neurothekeoma

(IHC?)

Answer 13

Nests and fascicles of epithelioid or spindled cells with little myxoid stroma.

S100- but S100A6+

Question 14

Malignant peripheral nerve sheath tumor (MPNST) (neurofibrosarcoma, malignant schwannoma)

Answer 14

Malignant transfomration of usually plexiform neurofibromas, with intersecting fascicles of spindle cells in an expansile growth pattern.

Question 15

Cutaneous ganglioneuroma

Answer 15

Mixture of schwann cells (uniform wavy nuclei) and large polygonal ganglion cells.

Question 16

Perineuroma

Answer 16

Fascicles of spindle cells with elongate bipolar processes. Can be parallel or concentric / onion-skin.

Question 17

Glial heterotopia (nasal glioma)

Answer 17

Astrocytes with round vesicular nuclei in a loose neurofibrillary stroma

Question 18

Meningeal heterotopia (rudimentary meningocele)

Answer 18

Pseudovascular spaces lined by meningothelial cells dissecting through collagen. May have psammoma bodies.

Question 19

Answer 19

Neurofibroma

Question 20

Answer 20

Plexiform neurofibroma

Question 21

Answer 21

Schwannoma

Question 22

Answer 22

Ancient schwannoma

Question 23

Answer 23

Traumatic neuroma

Question 24

Answer 24

Palisaded encapsulated neuroma

Question 25

Answer 25

Supernumerary digit

Question 26

Answer 26

Merkel cell carcinoma

Question 27

Answer 27

Granular cell tumor

Question 28

Answer 28

Myxoid neurothekeoma

Question 29

Answer 29

Cellular neurothekeoma

Question 30

Answer 30

Malignant peripheral nerve sheath tumor (MPNST)

Question 31

Answer 31

Cutaneous ganglioglioma

Question 32

Answer 32

Sclerosing perineuroma

Question 33

Answer 33

Nasal glioma

Question 34

Answer 34

Rudimentary meningocele