Dermatopathology Flashcards
Describe vitiligo
Partial or complete loss of melanocytes
Well demarcated macules/patches
Hand/wrist, axillae, perioral/periorbital, anogenital
Pathogenesis: autoimmune
What is albinism caused by?
it’s usually an inherited defect in tyrosinase
there is no melanin produced
in contrast to vitiligo, there are normal melanocytes in albinism, there just isn’t the enzyme necessary for normal function
What are the two general causes of pigmented lesions?
- excess melanin
- increased number of melanocytes
What are three examples of pigmented lesions due to excess melanin?
freckle
melasma
solar lentigo
What are two examples of pigmented lesions due to increased number of melanocytes?
melanocyte hyperplasia - lentigo simplex
melanocytic neoplasis - nevi, melanoma
What is the technical term for a freckle?
ephelis
ephelides
Under histology, what do freckles look like?
increased pigment in basal melanocytes
normal number of melanocytes
Describe melasma.
it’s mask-like hyperpigmentaiton on forehead and cheeks due to increased pigment transfer from melanocytes to keratinocytes
occurs in pregnancy or oral contraceptive use
usually will resolve
WHat is a solar lentigo?
a hyperpigmentation of the basal epidermis due to excess melanin production
it occurs in the elderly in areas of heavy sun exposure - it’s a protective mechanisms of the melanocytes
Describe lentigo simplex.
it’s localized hyperplasis of melanocytes
it can occur in all ages and isn’t related to sun
you get small brown macules anywhere on the skin
it results from increased number of melanocytes, resulting in increased pigment in stratum ocrneum and basal epidermis\
ITS AN EXAMPLE OF MELANOCYTIC HYPERPLASIA
In terms of skin neoplasia, what is a benign neoplasia and a malignant neoplasia
a benign neoplasm has no capability for metastasis - this includes those neoplasia that look like they COULD become metastatic, but haven’t crossed the basement membrane yet
malignant neoplasma have the potential for metastasis and have crossed the basement membrane
Is squamous cell carinoma in situ melignant or benign?
it’s still considered benign because it hasn’t crossed the basement membrane
this means it’s NOT CANCER
What are some benign neoplasia of the skin?
Melanocytic: Nevi
Epithelial: AK, adenomas
Stromal: leiomyoma, hemangioma
What are some malignant neoplasia of the skin?
Melanocytic: Melanoma
Epithelial: SCC, BCC
Stromal: DFSP, leiomyosarcoma, angiosarcoma
What are the 3 lifes stages of a nevi?
- junctional (at the junction of the epidermis and dermis - but not in the dermis yet)
- compound (in both epidermis and dermis)
- dermal (loss of the junctional part and only in the dermis)
WHat is the msot common mutatoin in a nevi?
BRAF
What’s the clinical treatment for a spitz nevus?
you have to take the whole thing off whenever you get path report saying its a spitz because they’re very hard to predict and it’s better to just remove the whole thing