Week 1 - Derm Flashcards
Vitiligo
- Partial or complete LOSS of melanocytes
- Due to autoimmune
- T-cells attack melanocytes in skin and cause destruction of melanocytes resulting in hypopigmented skin
**Autoimmune lymphocyte mediated melanocyte destruction (normal enzyme)
Albinism
- No melanin production/decreased production
- Inherited defect in Tyrosinase enzyme
- Normal number of melanocytes
***Congenital abscence of enzyme and melanin is not made/decreased.
What are three pigmented lesions due to excess melanin?
- Freckle
- Melasma
- Solar lentigo
What three pigmented lesions due to increased number of melanocytes?
- Melanocyte hyperplasia
- lentigo simplex
- Melanocytic neoplasia
- Nevi
- Melanoma
Freckle
- a.k.a Ephelis, Ephelides
- small tan red macules arising in childhood
- fade and reappear in cycle
- Histology: increased pigment in basale melanocytes
- overactive melanocytes due to sun exposure
Melasma
- Mask-like facial hyperpigmentation
- usually on cheeks, forehead, temples
- bilateral cheeks of face in “butterfly” pattern
- Melanocytes have enhanced pigment transfer to keratinocytes or macrophages
- thought to be estrogen related (pregnancy, oral contraceptives, hydantoin)
- resolves after pregnancy
Solar Lentigo
- Hyperpigmentation of basale epidermis due to excess melanin production
- Sun protective mechanism of melanocytes
- too much sun exposure over a lifetime
- Typical farmer (>70 years old)
Lentigo Simplex
- Localized hyperplasia of melanocytes
- Small brown macules
- Not sun related
- All ages
***Histopathology: Increased melanocytes, increased pigment in stratum corneum and basale epidermis, rete ridges elongated/thinned
What is neoplasia?
Genetically abnormal growth (irregular cell growth).
What is cancer?
Malignant neoplasm
Benign neoplasia
- Neoplasm with no capability for metastasis
- Can be destructive or symptomatic
Malignant neoplasia
- Neoplasm with potential for metastasis and subsequently growth/proliferation at distant site
- Often locally destructive, but may not be
Nevi
- Benign neoplasms of melanocytes
- Many Types:
- Acquired/congenital = typical mole
- Junctional (epidermal), Compound (epidermal/dermal), or Dermal
- Spitz/spitzoid
- Atypical (dysplastic)
- Dermal variants
- Blue nevus
Spitz nevi
Difficult to distinguish from melanoma under microscope occasionally.
ALL HAVE TO BE EXCISED.
- don’t know how they will behave
- difficult to judge malignant potential
Dysplastic Nevi (DPN)
- Atypical nevi (mild, moderate, severe atypia)
- Isolated dysplastic nevus = probably no risk or minimal risk of melanoma
- Multiple dysplastic nevi = marker of increased risk of melanoma
***Should excise moderate/severe dysplastic nevi.
Malignant neoplasm
- Malignant neoplasm of melanocytes
- Most arise in skin (can arise in oral/anogenital mucosa, meninges, esophagus, eye)
- Usually asymptomatic, may itch
- Change in color or size of pre-existing lesion
- RISK FACTORS: fair skin, sun exposre, many DPN
ABCD’s of Melanoma
- Asymmetry
- Border
- Color
- Diameter (>6 mm = penicl eraser)
Melanoma in situ
Localized to epidermis
(does not cross basement membrane)
***Benign, but likely to become malignant at some point
Breslow depth
How deep melanoma invades into the dermis.
- Probability to metastasize is best predicted by depth of invasion
- ***Best prognostic indicator***
- measured in millimeters
Breslow depth and survival rates
- <1mm: 5 year survival is 95-100%
- 1-2mm: 5 year survival is 80-96%
- 2.1-4mm: 5 year survival is 60-75%
- >4mm: 5 year survival is 37-50%
Other prognostic indicators
- Ulceration (usually bad, rapidly growing)
- Mitotic rate
- Sentinel lymph node biopsy
- Clark level (I-V)
- Gregression
- Inflammatory pattern
Seborrheic keratosis
- Most common epithelial neoplasm
- sign of aging
- benign epithelial proliferations
- “Stuck on” brown velvety papules/plaques
- exuberant keratin formation
- variable melanin
- sharply demarcated
Fibroepithelial polyp/Acrochordon
Skin Tag
- Soft flesh colored bag-like tumor with stalk
- Inconsequential
- very common
- not neoplastic
- may increase in pregnancy
- may be increased in diabetes, obesity
Epithelial Cyst
- Down growth of epidermis which becomes cystic
- Filled with keratin
- Subcutaneous or dermal nodule
- Rupture easily and become inflammed
- Subtypes:
- Epidermal
- Pilar
- Dermoid
- Steatocystoma multiplex
Actinic keratosis
- Benign neoplasm of epidermis
- may preced sqaumous cell carcinoma
- Induced by sunlight, ionizing radiation, arsenicals, hydrocarbons
- Rough spots on skin
- Cytologic atypia of basale layer, hyperkeratotic
- usually scaly and erythematous papules or plaques
How do you treat actinic keratosis?
- Liquid nitrogen
- curettage
- topical chemotherapy
Types of Squamous cell carcinoma
- In situ: contained above the basement membrane
- Invasive: invades basement membrane and dermis (malignant)
Clinical presentation of Squamous Cell Carcinoma
- Usually very scaly, red, raised
- common on sun exposed skin in older people
- Risk factors: sun, carcinogens, chronic ulcer, old burn scar
- Less than 5% will metastasize
Basal cell carcinoma
- Most common human malignancy
- slow growing, usually older adults
- Appearance: pearly papule with telangiectasia (small dilated blood vessels near the surface)
- arise from base of epidermis
- Risk factors: sun exposure, light pigment, xeroderma pigmentosum
Gorlin Syndrome
- Basal cell Nevus syndrome
- Dominant inheritance (rare)
- tumor suppressor gene is mutated
- BCC at early age with abnormalities of bone, nervous system, eyes, and reproductive organs
Cowden’s syndrome
- Hereditary condition prone to multiple hamartomas and malignancy
- Skin: multiple trichilemmomas (benign proliferation of hair follicle epithelium), benign keratoses on acral skin
- Mucosal papules, cobblestoning tongue
- Internal: breast, endometrial, and thyroid carcinoma
- cerebellar lesions
- Mutation in PTEN tumor suppressor gene
Sebaceous hyperplasia
- Acquired, localized increase in sebaceous glands
- Non-neoplastic
- Glands larger than normal
- Common on the face
- yellow papule
Sebaceous adenoma
- Benign neoplasm
- Lobular circumscribed proliferation of sebocytes and the peripheral basaloid epithelial cells
Sebaceous carcinoma
- Malignant neoplasm (cancer)
- Most are periocular (inner/outer eye lid)
- A periocular sebaceous neoplasm is most likely carcinoma, not adenoma or hyperplasia
- Extraocular forms are less common, but more likely to occur in Muir Torre syndrome
- Metastasis common (death in 20%)
Muir-Torre Syndrome
- Hereditary syndrome
- Germline mutation is DNA mismatch repair proteins
- **MLH1, **MSH2, MSH6, PMS2
- repair errors in base pairing during replication, especially in 1-2 bp repeats
- Skin: sebaceous adenoma and carcinoma, keratoacanthomas
- Internal: carinomas of the colon/rectum, endometrium, ovarian
- subset of hereditary non-polypsis colorectal carcinoma syndrome (HNPCC)
Who do you test for Muir Torre Syndrome (MTS)?
Young/adult patients with sebaceous adenoma or carcinoma.
Merkel Cell Carcinoma
- very aggressive epithelial neoplasm
- highly fatal due to metastasis
- most caused by polyomavirus
Dermatofibroma
- a.k.a. benign fibrous histiocytoma
- very common dermal proliferation of histiocytes and fibroblasts
- extremely firm, tan/brown papules
- commonly on legs
Dermatofibrosarcoma Protuberans (DFSP)
- Malignant form of a spindle cell stromal neoplasm
- locally aggressive
- rarely metastasize
- Protuberant nodule with a firm plauq
- honeycomb infiltration of fat
Hemangioma
- Benign vascular neoplasm
- well formed vascular spaces in dermis
Angiosarcoma
- Malignant
- Very aggressive in skin and internally
- usually fatal
- hard to treat/cure
Cutaneous T-cell lymphoma
- T-cells arise in marrow and travel to skin
- Usually very slowly progressive disease
- Age: >40 years
- Looks like psoriasis, eczema, etc. in early stage
- nodules come later
Mycosis Fungoides
- Most common type of Cutaneous T-cell Lymphoma
- Neoplastic CD4+ cells
- Infiltrate the epidermis and form clusters
- T-cells invade the epidermis
- Patchy, circular rashes
Cutaneous B-cell Lymphoma
- Less common than T-cell lymphoma
- Usually solitary of few nodules rather than patches/plaques
- Usually good prognosis
- Must exclude secondary cutaneous involvement by nodal lymphoma
Mastocytosis
- Mast cells originate in the marrow and travel to the skin
- Classified by cutaneous vs. systemic
- Urticaria pigmentosa: localized to skin
- Darier’s sign (histamine)
- Systemic mastocytosis: organ involvement
- Pruritis, flushing, runny nose, bleeding (heparin)
When do you do a shave biopsy?
**Superficial lesions**
- BCC, AK, SCC in situ, pigmented macules
- Better cosmetics
- No sutures
- Electrocautery
When do you do a punch biopsy?
Neoplasms involving the dermis.
- Nodular BCC
- SCC
- Melanoma
- Most RASHES
- Requires sutures
- Various sizes 4mm-8mm
What biopsy should a doc perform if they do not know what type of neoplasm?
***IF YOU DON’T KNOW,
DO A PUNCH BIOPSY!!!
