Week 1 - Disorders of Cutaneous Pigmentation & Cutaneous Neoplasms Flashcards
Neoplasms usually arise from. . .
the epidermis & the dermis
Dermis
Consists of collage/elastic fibers, peripheral nerves, muscle, fat, cartilage
Vitiligo
Partial or complete loss of melanocytes, well demaracated macules/patches, hand/wrist, axillae, perioral/periorbital, anogenital
Pathogenesis: autoimmune - T cells attack melanocytes of skin & destroy them - then you get hypopigmented cells
Neoplasia
Proliferation of genetically abnormal cells - clonal population or proliferation of cells that can escape the normal cell checkpoints
Cancer
Malignant Neoplasm
Benign vs. Malignant
Benign = can't metastasis Malignant = has potential (does not have to) metastasize
Albinism
No melanin produced (or decreased melanin)
Inherited defect in tyrosinase!! (normal number of melanocytes)
-Congenital absence of enzyme and melanin is not made or is decreased
Stromal Neoplasms
Neoplasms involving connective tissue
Nevus (mole)
Benign neoplasms of melanocytes, congenital or acquired - most have mutations (BRAF most common)
How do we predict the probability of melanoma to metastasize?
Depth of invasion
What is Breslow’s depth?
It is the probability to metastasize that is predicted by depth of invasion of the melanoma
- Measured in millimeters
- Best indicator of probability to metastasize
Breslow’s depth
How deep melanoma invades into the dermis (measure from the granular layer to the lowest melanocyte)
-Best prognostic indicator!!
Sentinel lymph node biopsy:
Usually for melanomas > 1 mm in thickness - melanomas like to go to lymph nodes (they usually go here first - so if melanoma isn’t here, it usually hasn’t metastasized)
Breslow depth & Survival:
4 mm: 5 yr sur. is 37-50%
Next most imp. prognostic indicator (after Breslow depth for melanoma):
Ulceration (usually growing very fast), mitotic rate of cells
Squamous cell carcinomas
Almost all are sun-related (sometimes related to radiation)
Basal cell carcinoma
Most common human malignancy - rarely metastasizes - risk factors include sun exposure, XP, light pigment - can be ulcerated, large papules on the nose
Cowden’s syndrome & Muir Torre Syndrome - common symptom:
Adnexal neoplasms/proliferations: differentiate toward hair follicle/glands, benign and malignant types
Cowden’s Syndrome:
Hereditary condition prone to multiple hamartomas and malignancy
Skin: multiple trichilemmomas (face- 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) <– KNOW!
Adenoma
Benign tumor of epithelial tissue
carcinoma
Malignant tumor of epithelial tissue
Multi-Torre Syndrome:
- Hereditary syndrome: germline mutations in DNA mismatch repair proteins: MLH1, MSH2, MSH6, PMS2
- These repair errors in base pairing during replication, especially in 1-2 bp repeats (microsatellites)
- Skin: sebaceous adenoma and carcinoma, keratoacanthomas
- Internal carcinomas: Colon/rectal, endometrial, ovarian
- Represents subset of hereditary non-polyposis colorectal carcinoma syndrome (HNPCC)
Merkel Cells
Touch, tactile cells
What should you do when biopsying a lesion to send the pathologist?
(1) Have to get a good sample & have a good description (history) sent to the pathologist
(2) Be overly descriptive for pathologist
- Never use terms like rash or lesion
- Be as descriptive as possible
THINK ABOUT DEPTH -take angriest looking biopsy sample - use punch biopsy if in doubt
What type of biopsy should you do on a rash?
Punch biopsy!
