Disorders of Pigmentation & Melanocytes, Benign Epithelial Tumors, Malignant Epidermal Tumors Flashcards

Question

Vitiligo vs Albinism

Answer 1

Vitiligo is autoimmune lymphocyte mediated melanocyte destruction – normal enzyme associated with other autoimmune disorders: pernicious anemia, thyroiditis Albinism is congenital absence of enzyme and melanin is not made or is decreased Enzyme loss of defect in transport to melanosomes

Answer 2

Due to excess melanin Freckle Melasma Solar lentigo ``` Due to increased number of melanocytes Melanocyte hyperplasia Lentigo simplex Melanocytic neoplasia Nevi Melanoma ```

Answer 3

Pregnancy, oral contraceptives, hydantoin Mask like facial hyperpigmentation Cheeks, forehead, temples Sunlight makes it worse Melanocytes have enhanced pigment transfer to keratinocytes or macrophages Resolves after pregnancy over or drug discontinued

Answer 4

Hyperpigmentation of basal epidermis due to excess melanin production Sun protective mechanism of melanocytes

Answer 5

``` Localized hyperplasia of melanocytes All ages Not sun related (vs. solar lentigo) Small brown macules Histopathology: Increased melanocytes, increased pigment in stratum corneum and basal epidermis, rete ridges elongated/thinned ```

Answer 6

malignant CAN (but not necessarily has) metastasize

Answer 7

Benign Definition: Neoplasm with no capability for metastasis Can be destructive or symptomatic – this does NOT define malignancy! Malignant Definition: Neoplasm with potential for metastasis and subsequently growth/proliferation at distant site Often locally destructive but may not be!

Answer 8

Benign neoplasms of melanocytes Congenital or acquired Most have mutations (BRAF most common) Common: Acquired or congenital Congenital: Large ones have increased risk of melanoma Blue: confused with melanoma clinically Spitz: difficult to distinguish from melanoma under microscope occasionally Halo: immune reaction to nevus cells Dysplastic/Atypical: potential precursor of melanoma

Answer 9

All Spitz/spitzoid lesions should be excised Unpredictable biologic behavior Many can be reliably classified as benign Others however difficult to judge malignant potential

Answer 10

Dark blue/brown papules Often clinically concerning for melanoma Benign Deep blue color due to deep pigmentation Tyndall effect – light scatter properties Entirely dermal proliferation of spindled melanocytes with many melanophages

Answer 11

Ota: Peri-ocular, intra-ocular dermal melanocytic nevus Ito: Mongolian spot, same type of lesion, different site

Answer 12

1978: families with many moles and high incidence of melanoma (Dysplastic nevus syndrome) Later sporadic cases described Sporadic syndrome is more common (2-17% of population?) Multiple dysplastic nevi = marker of increased risk of melanoma Isolated dysplastic nevus = probably no or only minimal risk of melanoma Usually graded by pathologist Mild, moderate, severe atypia Can excise mild depending on clinical circumstances, should excise mod/severe

Answer 13

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 Usually asymptomatic, may itch Change in color or size of pre-existing lesion ``` CLASSIC teaching is the ABCD’s: Asymmetry Border Color Diameter (>6mm or pencil eraser) ``` Only reliable way to exclude melanoma is to biopsy Many dermatologists believe that if a patient is concerned about a pigmented lesion that it should be biopsied if requested, even if it looks benign to you Options for patients with many atypical nevi: photos, frequent follow-up

Answer 14

``` Probability to metastasize is best predicted by depth of invasion This is known as Breslow’s depth Measured in **millimeters** Many prognosticators but ***Breslow depth is best*** Sentinel lymph node biopsy Usually for melanomas > 1 mm thickness ```

Answer 15

Next most important: Ulceration, mitotic rate For thin melanoma only (< 1mm) Clark level (essentially a less accurate Breslow) I – in situ II – few cells in papillary dermis III – melanoma fills papillary dermis IV – reticular dermis V – subcutis Others: regression, inflammatory pattern, etc. Breslow depth is best

Answer 16

``` 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 ``` Sharply demarcated Variable melanin/histologically overlap with lentigo Exuberant keratin formation Horn cysts

Answer 17

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

Answer 18

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

Answer 19

Benign neoplasm of epidermis (may precede squamous cell carcinoma) Induced by sunlight (most common), ionizing radiation, arsenicals, hydrocarbons Rough spots on skin (less than 1 cm) Sun exposed skin Cytologic atypia of basal layer, hyperkeratosis Some will progress to squamous cell carcinoma (malignant) if untreated (most likely 1%) Treated by liquid nitrogen, curettage, topical chemotherapy

Answer 20

Common neoplasm on sun exposed skin in older people Risk factors sun (#1), carcinogens, chronic ulcer, old burn scar, Also xeroderma pigmentosum, chemotherapy or organ transplant In situ: contained above the basement membrane (full thickness atypia) Invasive: invades basement membrane and dermis Less than 5% will metastasize

Answer 21

``` Most common human malignancy Slow growing, usually older adults Rarely metastasize Risk factors: sun exposure, light pigment, XP Pearly papule with telangiectasia ``` Resemble basal cell layer of epidermis Arise from base of epidermis, possibly hair follicle derived (controversial) Clefts are common between base of neoplasm and dermis

Answer 22

Differentiate toward hair follicle, eccrine, sebaceous, eccrine and apocrine glands Benign and malignant types Too many to learn realistically unless a pathologist

Answer 23

Hereditary condition prone to multiple hamartomas and malignancy Skin: multiple trichilemmomas (Benign proliferation of hair follicle epithelium) (face), benign keratoses on acral skin Mucosal papules, cobblestoning tongue Internal: breast, endometrial and thyroid carcinoma Cerebellar lesions Mutation in PTEN (tumor suppressor gene)

Answer 24

Acquired, localized increase in sebaceous glands, not neoplastic Glands larger than normal Common on the face Yellow papule

Answer 25

Benign neoplasm | Lobular circumscribed proliferation of sebocytes and the peripheral basaloid epithelial cells

Answer 26

Malignant neoplasm Most are periocular (inner/outer lid) A periocular sebaceous neoplasm is most likely carcinoma, not adenoma or hyperplasia Extraocular forms less common but more likely to occur in Muir Torre syndrome Metastasis common, death in 20%

Answer 27

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) Young/adult patient with sebaceous adenoma or carcinoma, test for MTS Immunohistochemistry Fast, relatively inexpensive Highly sensitive If loss of staining (indicating loss of DNA mismatch repair protein), genetic testing for confirmation

Answer 28

benign | dimple test

Answer 29

Well formed vascular spaces in dermis | Clinically must separate from malignant vascular neoplasms (Kaposi’s sarcoma, angiosarcoma)

Answer 30

For rashes – non-ulcerated/intact skin, usually sample center and edge Discrete lesions Needs to be representative in horizontal AND vertical axis Think about depth

Answer 31

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

Disorders of Pigmentation & Melanocytes, Benign Epithelial Tumors, Malignant Epidermal Tumors Flashcards

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