Dermatopathology I Flashcards
Vitiligo:
Chronic depigmenting condition from complete loss of epidermal melanocytes.
Vitiligo cause:
Autoantibody against melanin-concentrating hormone receptor 1 in serum.
Vitiligo repigmentation:
Begins around hair follicles that look like freckles and become confluent.
Ephelis (4):
Freckle
- Basal layer hyperpigmentation
- Appear after sun exposure in lightly pigmented kids
- Darken with sun exposure
- No risk of malignancy
Lentigo (3):
- Small circumscribed brown macular lesions
- Hyperpigmentation of cells just above the basement membrane
- Do not darken with sun exposure
Melanocytic nevi gross features (5):
- Tan to brown
- Uniformly pigmented
- Small
- Flat to elevated
- Well-defined, rounded borders
Melanocytic nevi histological features (5):
- Sharply defined
- Well nested at the dermal-epidermal junction
- Melanocytes mature as they descend in dermis
- No deep mitoses
- No deep pigment in melanocytic nests
Location of melanocytic nests in junctional melanocytic nevus:
Tips and sides of rete.
Compound melanocytic nevus histologic features:
Histologic features of junctional nevus + nests and cords of nevus cells in underlying dermis.
Dermal melanocytic nevus histologic feature:
Epidermal nests are lost completely
Spitz Nevus (6):
- Composed of spindle and/or epithelioid cells
- Dyskeratotic melanocytes
- Sharply defined laterally
- Line symmetry from left to right
- Clefts separating nests from keratinocytes
- Deep red color
Kamino bodies:
Dyskeratotic melanocytes
- Eosinophilic bodies along dermal-epidermal junction
Dysplastic (atypical) melanocytic nevus (3):
- Commonly large, oval and multiple
- Irregular pigment common
- Fading border/fried egg appearance
Dysplastic melanocytic nevus histologic features (3):
- Horizontally oriented nests with bridging of adjacent rete
- Nests are at the tips and sides of rete
- Cytologic atypia: hyperchromatic, enlarged nuclei
Number 1 cause of skin cancer deaths worldwide:
Melanoma
Melanoma:
Malignancy of pigment-producing cells (melanocytes)
Melanoma stage determination:
Vertical phase depth.
ABCDE of melanoma:
A: Asymmetry B: Border irregularity C: Color variation D: Diameter > 6mm E: Evolving
Radial growth phase (2):
Melanoma-in-situ
- Horizontal spread of melanoma cells within the epidermis and superficial dermis
- Tumor cell slack the ability to metastasize
Vertical growth phase (4):
- Tumor cells invade downward into deeper dermal layers as a mass
- Cells with metastatic potential emerge
- Invading cells do not mature
- Grossly, a nodule appears
Most common melanoma subtype:
Superficial spreading
Superficial spreading melanoma is usually found on:
Sun-exposed skin, typically on backs of men and lower legs of women, but any age, any place.
Superficial spreading malignant melanoma histologic features (5):
- Buckshot scatter of atypical melanocytes within the epidermis
- Typically not symmetrical
- Typically fails to mature from top to bottom
- Deep mitoses may be present
- Cytologic atypia
Lentigo maligna melanoma (4):
- Indolent, slow growing lesion
- Typically on the face of old men
- Long radial growth phase, 10-50 years
- Starts as a tan-brown macule and gradually enlarges developing a darker, asymmetric foci
Lentigo maligna histologic features (3):
Melanoma-in-situ
- Poorly nested and confluent melanocytes at the dermal epidermal junction
- Adnexal extension
- Heavily sun damaged skin
Acral lentiginous melanoma (2):
- Most common melanoma in African Americans and Asians
- Palms, soles, beneath nail plate
Nodular melanoma histologic features (4):
- Vertical growth phase melanoma
- No apparent radial growth phase
- Dermal growth occurs in isolation or in association with an epidermal component
- Mitoses are frequent and often atypical
Melanoma prognostic factors (5):
- Tumor thickness
- Mitotic rate
- Ulceration
- Lymph node involvement
- Distant metastases
Most common benign tumor in older individuals:
Seborrheic keratosis
Seborrheic keratosis (4):
- Begin as light brown flat macules
- Develop velvety or waxy to finely verrucous surface
- Color may vary from pink to dark brown or black
- Appear stuck on and crumble with scraping
Dermatosis papulosa nigra (3):
- Brown to black, smooth, dome-shaped papules
- Most often seen in African Americans
- Sub-type of seborrheic keratosis
Acanthosis nigrans (5):
- Hyperpigmentation is first sign
- Hyperplasia of stratum spinosum makes skin thick and velvety
- Usually found in folds of the neck, axilla and groin
- Associated with endocrine abnormalites
- Associated with visceral malignancy in middle-aged and older
Epidermal (inclusion) cyst histologic features:
Cyst wall resembles normal epidermis, filled with strands of keratin
Earliest identifiable lesion that can develop into squamous cell carcinoma (SCC):
Actinic keratosis
Actinic keratosis risk factors (3):
- Years of sun exposure
- Fair skin
- Immunosuppression
Actinic keratosis appearance (3):
- Initially may be hard to see but will have areas of rough or “gritty” skin
- Discrete, scaly, feels like “broken glass” surface lesion
- Develop into poorly-demarcated, slightly erythematous papule or plaque with scale
Most common cancer in the US:
Nonmelanoma Skin Cancer (NMSC)
Majority of NMSC:
Basal cell carcinomas (BCC)
Bowen disease:
Subtype of SCC-in-situ characterized by a sharply demarcated pink plaque and can arise on non-sun-exposed skin.
Erythroplasia of Queyrat:
Bowen disease of the glans penis, which manifests as one or more velvety red plaques
Invasive SCC (2):
- Raised, firm, pink-to-flesh colored keratotic papule or plaque arising on sun-exposed skin
- Surface changes: scaling, ulceration, crusting, or cutaneous horn
Keratoacanthoma (5):
- Benign epithelial tumor that may progress to SCC
- Appear suddenly on actinically-damaged skin
- Spontaneously regress after a few months
- Red to flesh colored dome-shaped papule with a central crater filled with keratinous plug
- Treat the same as SCC
Basal cell carcinoma (BCC) (3):
- Pluripotential cells in the basal layer of the epidermis or follicular structures
- Can cause local destruction and disfigurement
- Slow grown and rarely metastasizes
Nodular BCC (7):
- Face most common site
- Waxy papules with central depression
- Pearly appearance
- Erosion, ulceration or crusting
- Bleeding with minor trauma
- Rolled border
- Telangiectasias over the surface
Superficial BCC (4):
- Trunk is most common site
- Slight scaly papule or plaque
- Light red color
- Atrophic center with fine translucent micropapules on rim
