Dermatopathology: Pigmented Lesions Flashcards
Which layer of skin are melanocytes normally found in?
Basal layer
Does melanocyte density vary with race?
No
Organelle of melanocytes that is incorporated into keratinocytes
Melanosome
Autoimmune destruction of melanocytes
Vitiligo
What races are affected by Vitiligo?
All
Generalized form of vitiligo that affects almost the entire body
Vitiligo universalis
Condition involving circumscribed amelanotic macules of skin and mucous membranes
Vitiligo
10-15% of patients with generalized vitiligo have this
Systemic autoimmune disease
(e.g. Hashimoto’s thyroiditis, Pernicious anemia, Lupus)
Condition where histology shows absent melanocytes
Vitiligo
Inherited reduction or absence of pigmentation
Albinism
Inheritance pattern of albinism
Autosomal recessive
Albinism is usually due to a mutation in this
Tyrosinase
Amount of melanocytes in Vitiligo
Absent
Amount of melanocytes in Albinism
Normal numbers
Is Vitiligo S100 positive?
No; absent melanocytes
Is Albinism S100 positive?
Yes; melanocytes are present in normal numbers
Patients with Albinism have increased rates of this cancer
Squamous cell carcinomas
UV light induced small pigmented molecule
Ephelis
Does an Ephelis occur with the sun?
Yes
Localized area of non-nested melanocyte hyperplasia
Lentigo
Form of Lentigo that occurs in childhood
Lentigo simplex
Form of Lentigo that has no relation to sun exposure
Lentigo simplex
Form of Lentigo that occurs in elderly
Solar lentigo
Form of Lentigo that involves sun damaged skin
Solar lentigo
Form of Lentigo that is typically a small (<1cm) tan brown macule
Lentigo simplex
Form of Lentigo that is typically 1-3cm and may be confluent
Solar lentigo
Form of Lentigo that occurs in childhood, has no relation to sun exposure, and is typically a small (<1cm) tan brown macule
Lentigo simplex
Form of Lentigo that occurs in elderly, to sun damaged skin, and is typically 1-3cm and may be confluent
Solar lentigo
Localized hyperpigmentation of mucosal site
Mostly on lip, oral mucosa, genitals
Melanotic macule
Does lentigo involve nesting?
No
Does a melanotic macule involve nesting?
No
Inheritance pattern of Peutz-Jaeger Syndrome
Autosomal dominant
Syndrome associated with melanotic macules
Involves multiple lentigines, usually orofacial
Peutz-Jaeger Syndrome
Syndrome associated with melanotic macules that involves Hamartomatous GI polyps
Peutz-Jaeger Syndrome
Peutz-Jaeger Syndrome has increased risk of these 2 types of cancer
Intestinal and breast cancer
Condition involving few to dozens of hamartomatous GI polyps that are usually lobulated with arborizing smooth muscle
Peutz-Jaeger Syndrome
Benign neoplasm of melanocytes
Melanocytic nevus
Is a melanocytic nevus nested?
Yes, if at dermal-epidermal junction
Most melanocytic nevi have mutations in either of these 2 oncogene pathways
RAS or BRAF
Type of melanocytic nevus that tend to be flat
Junctional nevus
Type of cells that are involved with regression
CD8+ T cells
Halo Nevus has an increased incidence in patients with this condition
Vitiligo
Numerous lymphocytes infiltrating the nevus and a pale halo around it indicate this process is occurring
Regression
Multiple or giant congenital nevi have association with this condition
Neurocutaneous melanosis
These have an association with neurocutaneous melanosis
Multiple or giant congenital nevi
CNS symptoms of neurocutaneous melanosis are due to this
Leptomeningeal melanocytosis
Most common activating mutation in malignant melanoma
BRAF
Drug that inhibits BRAF ser/thr protein kinase
Vemurafenib
Vemurafenib inhibits this
BRAF ser/thr protein kinase
Is used to treat melanoma
Mutation in this is more common in malignant melanoma in acral sites
kit
Do malignant melanomas arise from benign nevi?
Most do not
Diameter greater than this could indicate malignant melanoma
> 6mm (pencil eraser size)
This describes melanocytes at elevated levels of epidermis
Pagetoid
What are pagetoid melanocytes?
Melanocytes at elevated levels of epidermis
This describes melanocytes confluent along the dermo-epidermal junction
Lentiginous
What are Lentiginous melanocytes?
Melanocytes confluent along dermo-epidermal junction
Does melanoma in situ have a risk of metastasis?
No
What skin layer are malignant melanocytes located in melanoma in situ?
Limited to epidermis
Does melanoma have lentiginous or pagetoid growth?
Can have either
What skin layer are malignant melanocytes located in invasive melanoma?
Dermis
What is the most important factor of primary tumor in invasive melanoma?
Depth of invasion
Growth pattern of malignant melanoma along the plane of dermal-epidermal junction
Radial phase
Growth pattern of malignant melanoma that is downward into dermis
Vertical phase
Increasing depth of malignant melanoma has what effect on the ability to metastasize?
Increases
Vertical growth of malignant melanoma is correlated with mutations in this
p16
p16 mutations are correlated with this type of growth of malignant melanoma
Vertical phase
Form of melanoma in situ that typically involves sun damaged skin of elderly
Slowly expanding growth, may have no invasion
Lentigo maligna
What is the typical patient with Lentigo maligna?
Sun damaged skin of elderly
Does Lentigo maligna have invasion?
No; slow growing
What does Lentigo maligna look like?
Variable, asymmetric, but flat
Slow growing
Is a form of melanoma in situ
Invasive melanoma arising in Lentigo maligna
Lentigo maligna melanoma
What is the clinical appearance of Lentigo maligna melanoma?
Same as Lentigo maligna but with invasion
Nodular, thicker, ulcerated, rapidly changing area
Is Lentigo maligna related to sun exposure?
Yes, typically involves sun damaged skin of elderly
Is superficial spreading malignant melanoma related to sun exposure?
Yes, most arise from sun exposed skin
What is the prognosis of Superficial spreading malignant melanoma?
Relatively good
Tends to be more superficial, radial phase is prolonged
Uncommon form of invasive melanoma defined by lack of radial growth phase
Predominately invasive
Nodular melanoma
What defines nodular melanoma?
Lack of radial growth phase
Predominately invasive
Melanoma arising in palms, soles, subungual sites
Acral lentiginous melanoma
What population is Acral lentiginous melanoma more common in?
Non-Caucasians
Melanoma in palms, soles, subungual sites
c-kit may be involved
Acral lentiginous melanoma
S100, MelanA, Sox10, HMB45, Mart1 are markers for this
Malignant melanoma
Atypical nevus which does not fulfill criteria for malignancy
Dysplastic nevus
Can Dysplastic nevus evolve into melanoma?
It can yes
Multiple dysplastic nevi is a marker for what?
Increased whole body risk of melanoma
Dysplastic nevus syndrome is due to a mutation in this
CDKN2A (cyclic-dependent kinase inhibitor 2A)
CDKN2A mutation causes this condition
Dysplastic nevus syndrome
Patients with Dysplastic nevus syndrome have a high lifetime rate of this
Melanoma