Skin Pathology Flashcards
What are the 5 layers of the Epidermis?
- Stratum Basale
- Stratum Spinosum
- Stratum Granulosum
- Stratum Lucidum
- Stratum Corneum
Describe the gross appearance of Vitiligo. What populations does vitiligo affect? Are there any predisposing factors? What is the etiology? Microscopic Appearance?
Irregular, completely depigmented patches
Common and may affect any race
Familial predisposition
Unknown etiology, possibly autoimmune
Microscopic: The affected areas are devoid of melanocytes
Describe the gross appearance of Melasma.
What other condition(s) is it associated with?
Irregular blotchy patches of hyperpigmentation on the face
Associated with oral contraceptive use & pregnancy (“mask of pregnancy”); May regress after pregnancy
What is the common name for Ephelides?
Describe the gross appearance.
What populations are most susceptible?
Describe the microscopic appearance.
Freckles!
Light brown macules on face, shoulders, and chest
Common in fair-skinned children - Darken and fade with the season due to sunlight exposure
Microscopic appearance: Increased melanin deposition in the basal cell layer of the epidermis; Normal number of melanocytes
Describe Benign Lentigo.
Describe the microscopic appearance.
Benign, localized proliferation of melanocytes that appear
Small, oval, light brown macules
Microscopic appearance shows linear melanocytic hyperplasia
*you are not born with them necessarily (those would be congenital nevi, aka birthmarks)
Congenital (Birthmarks)
Present at birth
Giant congenital nevi have increased risk of developing melanoma
Nevocellular Nevus (Mole)
What is the etiology of a nevocellular nevus?
Describe their gross appearance.
Benign tumor of melanocytes (melanocytic nevus cells)
Clearly related to sun exposure
Gross appearance: Uniform tan to brown color
Sharp, well circumscribed borders
Tend to be stable in shape and size
Malignant transformation is uncommon
What types of nevi are there?
junctional, compound, and intradermal
How do Dysplastic Nevi (BK Moles) differ?
Describe their microscopic appearance.
Nevi are larger and irregular and may have pigment variation
Microscopic appearance: the nevus exhibits cytological and architectural atypia
What is Dysplastic Nevus Syndrome?
AD (CMM1 gene on chromosome 1)
Often have multiple dysplastic nevi
Increased risk of melanoma
Malignant Melanoma
What is the incidence of malignancy of melanocytes/what is the peak age range?
What are the risk factors?
Increasing at a rapid rate; Melanoma peaks in ages 40-70
Risk factors:
Chronic sun exposure, sunburns
Fair-skinned individuals
Dysplastic nevus syndrom
Familial melanoma is associated with loss of function mutation of the p16 tumor suppressor gene on chromosome 9e
What is the gross appearance for malignant melanomas?
Where are the most common locations on the body?
Asymmetric, irregular borders, variegated color, large diameter, enlarging, macule, papule, or nodule
Males: upper back
Females: back and legs
What are the different types of malignant melanomas?
Lentigo Maligna Melanoma
Superficial Spreading Melanoma
Acral-lentiginous melanoma
nodular melanoma
Where are Lentigo Malignant Melanomas found?
What is the prognosis?
Usually located on the face or neck of older individuals
Best prognosis
What is the growth pattern of a superficial spreading melanoma? How commonly does it occur?
Has a primarily horizontal growth pattern
Most common type of melanoma
What populations is acral-lentiginous melanoma most common in?
Where is it most commonly found on the body?
Most common melanoma in dark-skinned individuals
Affects palms, soles, and subungual area
What is the growth pattern of nodular melanoma?
What is its prognosis?
vertical growth pattern
Worst prognosis of the melanoma
What two methods are used to determine the prognosis of malignant melanomas?
Staging is by depth of invasion (vertical growth)
Breslow’s thickness
Clark’s levels