Disorders of cutaneous pigmentation - Jokinen Flashcards
Vitiligo
Hypopigmented disorder.
Autoimmune disease - partial or complete loss of melanocytes.
Albinism
No melanin produced (or decreased)
Inherited defect in tyrosinase
Pigmented lesions due to too much melanin (but normal # of melanocytes)
Freckle
Melasma - Though to be estrogen related.
“butterfly” distribution
This can go away.
Solar lentigo - Too much sun exposure over a lifetime.
Melanocytic Hyperplasia (too many melanocytes): Lentigo simplex
Not sun related. basically a small hyperpigmented macule.
Localized hyperplasia of melanocytes
Pigment tends to be uniform.
Benign Neoplasm
Neoplasm with no capability for metastasis
Can be destructive or symptomatic – this does NOT define malignancy
Malignant Neoplasm
Neoplasm with potential for metastasis and subsequently growth/proliferation at distant site
Often locally destructive but may not be!
Nevi
This is a Melanocytic Neoplasm.
Nevi are simply moles.
Melanocytes grow in nests along junction (junctional nevus - generally flat) and in time enter dermis (compound nevus) after aging become intradermal only. The junctional nevi are “bumpy”.
So as they raise - they become compound.
Dermal nevus - very raised nevus
What is a spitz nevi? How are they different?
Spitz nevi are unique. The melanocytes are irregular with larger nuclei. These are always taken out, always excised from patients.
What is blue nevus?
Nevus that are generally found on the head. These have elongated slender melanocytes.
Nevus of Ota/Ito?
These are congenital nevus where melanocytes start off in the dermis.
Ota: Peri-ocular, intra-ocular dermal melanocytic nevus
Ito: Mongolian spot, same type of lesion, different site
Dysplastic nevus syndrome
body covered with atypical nevus.
Malignant Melanoma
Malignant neoplasm of melanocytes
Used to be uniformly deadly
Most arise in skin
Other sites: oral/anogenital mucosa meninges, esophagus, eye
Risk factors: fair skin, sun exposure, many DPN
What are the ABCD’s of melanoma?
Asymmetry
Border
Color
Diameter (>6mm or pencil eraser)
Malignant melanoma vs melanoma in situ
Malignant melanoma has access to blood vessels - so it has invaded past basement membrane
In situ is still above the basement membrane and doesn’t have access to the blood vessels.
Breslow’s Depth
This is how deep melanoma invades into the dermis. This is the most important correlation to the probability for metastasis.
4mm: 5-year survival is 37-50%
It is from granular layer to deepest melanocyte
What is the best predictor that a malignant melanoma will metastasize??
Barlow’s depth
4mm: 5-year survival is 37-50%
Seborrheic keratosis
Sign of aging.
Benign epithelial proliferations that can look scary.
Due to excess of melanin, not an excess of melanocytes.
These are raised clinically. Completely benign.
Common epithelial neoplasm Trunk, head, neck are typical “stuck on” Brown and velvety papules/plaques Leser-Trelat Sign – paraneoplastic, rapid growth of numerous seborrheic keratoses
Skin tag/Fibroepithelial polyp/Acrochordon
Very common cutaneous lesion, not neoplastic
Soft flesh colored bag-like tumor with stalk
Inconsequential
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 inflamed
Subtypes: epidermal, pilar, dermoid, steatocystoma multiplex
Actinic keratosis
Sun related lesion.
Benign neoplasm of epidermis (may precede squamous cell carcinoma)
Scaly erythematous papules or plaques.
“old farmer”
Is an epithelial neoplasm that is benign (99% of the time).
Even though they are benign, they are treated by liquid nitrogen, curettage, topical chemotherapy
Squamous cell carcinoma - In Situ vs Malignant
In Situ - benign, hasn’t invaded basement membrane
Invasive - invaded past basement membrane and dermis.
less than 5% metastasize
Basal cell carcinoma
Most common malignancy.
Usually doesn’t metastasize.
Sun related.
Telangiectasia (widened small blood vessels)
These resemble basal cell layer of epidermis, but it is more likely that this carcinoma arises from base of epidermis, possibly hair follicle derived (controversial)
Adnexal Proliferations/Neoplasms
These are neoplasms that differentiate toward hair follicle, eccrine, sebaceous, eccrine and apocrine glands
Benign and malignant types
Main two are:
Cowden’s syndrome
Muir Torre syndrome
Cowden’s syndrome
Due to a mutation in PTEN (tumor suppressor gene)
Know that Trichilemmomas are associated with cowden’s syndrome.
Hereditary condition prone to multiple hamartomas and malignancy
Skin: multiple trichilemmomas (face), benign keratoses on acral skin
Mucosal papules, cobblestoning tongue
Internal: breast, endometrial and thyroid carcinoma
(trich = hair, so proliferation of hair follicle??)
Sebaceous carcinoma vs Sebaceous adenoma
Sebaceous carcinoma is the malignant form. Extraocular forms less common but more likely to occur in Muir Torre syndrome
Sebaceous adenoma is the benign form.
Muir-Torre Syndrome
Caused by germline mutations in DNA mismatch repair proteins: MLH1, MSH2, MSH6, PMS2
Skin: Sebaceous adenoma and carcinoma, keratoacanthomas
Internal carcinomas: Colon/rectal, endometrial, ovarian
Skin: Sebaceous adenoma and carcinoma, keratoacanthomas
Internal carcinomas: Colon/rectal, endometrial, ovarian
Very aggressive epithelial neoplasm
Most caused by a polyomavirus
50% rate of death. Widely metastasize to lymph nodes.
Dermatofibroma
Very common
Dermal proliferation of histiocytes and fibroblasts
Etiology unknown – many are clearly reactive hyperplasia (After bug bite) and resolve, others uncertain
Raised and firm.
The pinch test - pinch it and see if edges will dimple.
Dermatofibrosarcoma Protuberans (DFSP)
Well differentiated fibrosarcoma of skin
Rarely metastasize/locally aggressive
Protuberant nodule within a firm plaque
Often nodular in kids.
(may be a malignant dermatofibroma??)
Hemangioma vs Angiosarcoma
Hemangioma = Benign vascular neoplasm
Angiosarcoma = Malignant vascular neoplasm. Aggressive, very bad, kill!
Mycosis Fungoides
Type of T cell lymphoma.
Neoplastic cell is CD4+ T cell
T cells go into the epidermis.
When to shave vs when to punch for biopsy?
Shave: use for superficial lesions (many BCC, AK, SCC in situ, pigmented macules)
Better cosmetics, no sutures, electrocautery
Punch: use for neoplasms involving the dermis (nodular BCC, SCC, melanoma, etc.) and most rashes
Requires sutures
Various sizes 1.5 mm – 8 mm
