BENIGN AND MALIGNANT MELANOCYTIC TUMORS Flashcards
Usual ratio of melanocytes to keratinocytes
1:4 on the cheek
1:10 on the limbs
Melanocyte stains
(+) S100, Mart-1, HMB-45
How can you differentiate keratinocyte from melanocyte?
haloed nucleus WITHOUT cytoplasm = KERATINOCYTE
haloed nucleus WITH cytoplasm = MELANOCYTE
Ans
Keratinocyte
Keratinocyte
Melanocyte
- if may nesting, you have to think of nevus or something bad
*its difference from lentigo simplex is it has solar elastosis
Junctional Melanocytic Nevus
- Nests of melanocytes are at the tips of rete ridges
- starts and ends with a nest = BENIGN
- no sun damage/ solar elastosis points to a benign lesion
Compound Melanocytic Nevus
Nests of melanocytes are found at the tips of rete ridges and in the dermis
Intradermal Melanocytic Nevus
- Decrease in size of nest of melanocytes with depth
- Decrease in size of melanocytes with depth
What are the congenital features of nevus
*focal lang na melanocyte migration sa epidermis. benign pa rin
Identify
KAMINO bodies - Degenerated and hyalinized melanocytic aggregates along the dermoepidermal junction
- Can be composed of spindled cells, epithelioid cells or combination of both
- There is maturation with depth: Dermal nests and melanocytes are smaller than those in the junctional component
Seen in spitz nevus
Common Blue Nevus
- Fairly symmetric intradermal proliferation
*lentiginous spread - melanocytes are spread as single cells along the DEJ
What does it mean by shouldering phenomenon?
What are the features of dysplastic nevus?
Features of Junctional melanocytic nevus
Characteristics of Melanocytes showing cytological atypia
lentigo simplex
Spitz nevus
Blue nevus
Melanoma
- not symmetrical
- not circumscribed (does not start and end with a nest)
- melanocytes are atypical looking
- no maturation (cells at the bottom are bigger that the cells above)
- with solar elastosis
