Derm Path II Flashcards
What causes a freckle?
Increased melanin pigment production (that is distributed to keratinocyte)
How does a lentigo appear clinically?
Small, oval-tan brown spot that occurs at any age on the mucous membranes
What is a lentigo histologically?
A non-confluent typical single cell melanocytic hyperplasia along the basal layer
Differentiate nevi from lentigo histologically
nevi form hyperplastic NESTS of melanocytes
Nevi= Nests
What is the link between dysplastic nevi and melanoma?
People with dysplastic nevi have an increased risk of developing melanoma
Describe melanoma histologically
Confluent nests and single atypical melanocytes
There are melanocytes lined up next to each other, rather than being buffered in between by keratinocytes
Describe the progression of a melanocytic nevi from junction –> compound –> intradermal
Melanocyte at the junction –> compound (both in the eipdermis and dermis) –> intradermal
Take home: the melanocytic nevi progress deeper into the skin
What is one way of differentiating melanocytic nevi from melanoma?
Melanocytic nevi “mature” from nest cells to single cells in the dermis.
Melanoma cells do not mature- they just invade and take over
“Shouldering” of the epidermal component that extends at least 3 rett ridges beyond the dermal component suggest what type of skin finding?
Dysplastic nevi
Describe the “bridging” seen in dysplastic nevi
confluence of rete ridge nests
What is the worst prognostic factor for melanoma
Finding (even) a single cell in the sentinel lymph node
Which is more concerning, radial growth or vertical growth for melanoma?
Vertical growth- nodular and any invasive type of melanoma
Blood vessels are there in the dermis, so the cells can metastasize
Which are the two more important predisposing risk factors for melanoma?
1) Sun exposure (Men- upper back, women- posterior calf)
2) Inherited genes: CDKN2A, BRAF, NRAS, PTEN, C-KIT
Non sun-exposure melanomas are associated with which mutation?
C-KIT
Which two gene mutations are seen in both familial and sporadic melanoma cases?
BRAF and CDKN2A
CDKN2A is seen in more familial melanomas
BRAF are seen in more sporadic melanomas
there are specific BRAF and CDKN2A tx’s
What is the most important prognostic feature for invasive melanomas?
Breslow thickness
The more deep a melanoma goes, the greater its chance of metastasizing
“Buckshot” and “pagetoid spread” indicate what type of lesion?
melanoma
What is a follicular epidermal inclusion cyst?
hard nodule under skin- epidermis appears normal with a punctum in the middle of it.
Cyst with full thickeness epidermal layer- punctum open up and keratinous material comes out
Follicular Trichilemmomas are associated with what syndrome?
Cowden’s syndrome: PTEN mutation that leads to increased risks of breast, endometrial and thyroid cancers
Describe the histology of trichilemommas
Pushing border, some palisading cellular architecture with clear cell change
These are completely benign
What’s a way to distinguish a dermatofibroma from a melanoma
Squeeze it- dermatofibromas show a dimple sign
Name two histologic features characteristic of dermatofibroma
Tabeling of rete ridges
Collagen trapping
What are dermatofibrosarcoma protuberans
large nodules with multiple protuberances, most common on the trunk of young to middle aged adults
Describe the histology of a dermatofibrosarcoma protuberans
Dense proliferation of spindle cells in the dermis demonstrating a storiform (irregularly whorled pattern) of fibroblasts
