Benign Melanocytic Neoplasms Flashcards
What is the difference between ephelides and lentigo?
Ephelides can come and go with sun exposure
Pathogenesis of ephelides?
Increased melanogenesis and melanin transfer to keratinocytes
Histology of ephilids
Increased basilar keratinocyte pigmentation and enlarged melanocytes w/o increased density
Multiple cafe au lait macucles (CALMs) is a/w what conditions?
Russell-Silver, Bloom syndrome, Neurofibromatosis type 1>type 2, tuberous sclerosis, ataxia telangietasias, noonan sydrome, fanconi syndrome, mccune-albright syndrome; MEN-1
What are the CALMS like in Mccune Albright syndrome?
Fewer CALMs, larger, midline demarcation, segmental distribution, patter, broad bands along Blaschko lines
What are the CALMS like in NF type 1?
Can have superimposed lentigines
Which melanocytic lesion increases hair and can have acneiform lesions?
becker’s nevus
What is becker’s nevus a/w?
Hypoplasia of ipsilateral breast, areola, nipple and arm, ipsilateral arm shortening, lumar spina bifida, thoracic scoliosis, pectus carnatum, enlargement of the ipsilateral foot.
Do solar lentigines fade over time?
No
Histology of solar lentigines?
Dirty socks (hyperpigmentation of the bottom of the rete pegs), epidermal hypoplasia, and sun damage
What lentigos are in younger people?
Lentigo simplex and mucosal melanotic lesions
The most common location for lentigines or melanosis of the female genital area?
Labia minor most common
What can lentigo simplex and mucosal melanotic lesions be a/w?
Cronkhite-Canada, Carney complex (LAMB/NAME), LEOPARD (aka Noonan w/ multiple lentigines), Laugier-Hunziker, Bannayan-Riley-Ruvalcaba (penile), Peutz-Jeghers (especially oral/perioral), xeroderma pigmetosum, Cowden syndrome
Why are dermal melanocytosis grey-blue appearing
Tyndall effect
Extensive dermal melanocytosis could be related to which genetic disorders?
Phakomatosis cesioflammea (type II phakomatosis pigmentosvascularis (PPV)), phakomatosis cesiomarmorata (type V PPV)
Epidemiology of the nevus of Ota?
First year of life or puberty, increased in Asians and Blacks
Most common location of nevus of Ota?
Coalescing gray/blue mauces in V1/V2 distribution. frequent scleral involvment (60%); unilateral (90%)>bilateral
What is the mutation in nevus of Ota that degenerates to uveal melanoma?
GNAQ
What can nevus of Ota turn in to?
Uveal melanoma
What is nevus of Ito?
Located on shoulder, suprclavicular, scalpular regions; essentially no risk of progression to melanotic
What is a Hori’s nevus?
Acquired nevus of Ota-like macules bilateral zygomatic regions; Most common in East Asian females
What is a Sun’s nevus?
Acquired, unilateral (Only one sun) nevus. This is different because nevus of Ota/Ito are usually present at birth
Histology differences between nevus of Ota and dermal melanocytosis?
Elongated dendritic melanocytes are more numerous in nevus of Ota and involve levels of the dermis to varying degrees (superficial dominant, deep dominant, etc)
Epidemiology of blue nevi?
Onset is usually in childhood or adolescence 25% are cellular blue nevi
Most common sites of blue nevus?
Scalp, sacral area, distal extensor extremities
Where do the melanocytes that make up blue nevi come from?
They are retained melanocytes in the dermis that persist during embryogenesis rather than populating epidermis
What mutations can you see in blue nevi?
GNAQ and GNA11
What are the different variants of blue nevus?
Common blue nevi (<1cm), hands, feet, face scalp cellular (larger 1-3cm, favors buttocks or scalp) epithelioid blue nevus (a/w carney complex, trunk, and extremities) Malignant blue nevus (melanoma, GNAQ/GNA11, and BAP-1 mutations)
How to distinguish blue nevus from nevus of Ota or dermal melanocytosis?
Sclerotic collagen in the dermis which is seen in blue nevus and not in nevus of Ota or dermal melanocytosis
What blue nevus type does malignant blue nevus arise from?
Cellular blue nevus
What location is most common with malignant blue nevus?
Scalp
What two diseases can you see with eruptive acquired nevi?
Epidermolysis bullosa and LS+A
What is the abtopfung hypothesis
Nevus cells start as juncitonal proliferation–>subsequently migrate into dermis (compound) –> later become entirely intradermal –> may involute
What mutations are in nevi?
BRAF mutation in up to 80% more so than NRAS