Skin & Soft tissue Flashcards
Hurley Classification of Hidradenitis Suppurativa
Hurley Stage I: localized abscesses; no sinus tract, no scars
Hurley Stage II: recurrent abscesses, +sinus tracts, +scars, separated by areas of normal skin
Hurley Stage III: diffuse dz, multiple connected sinus tracts/abscesses/scars affecting entire area
Treatment of Hidradenitis Suppurativa based on Hurley Stage
HS I: Topical clina, antiseptic (chlorhexidine) washed, lifestyle mods
HS II: PO Doxy, +/- adalimumab
HS III: PO Doxy, PO Clinda/Rifampin/Antiandrogens (for refractory dz), +/- adalimumab, Surgical excision + STSG (for refractory dz to max medical tx)
Burns classification
1st degree: only epidermis (red, without blisters)
2nd degree: extends into dermis (painful, blisters)
superficial partial thickness: papillary dermis (moist, blanches)
deep partial thickness: reticular dermis (dry, less blanching, insensate)
3rd degree (full thickness): entire dermis (leathery, painless)
4th degree: into underlying fat, muscle, bone (black, eschar)
Nonmelanoma skin cancer (NMSC)
MC skin cancer. 2/2 to UV ray exposure.
Basal cell carcinoma
Squamous cell carcinoma: actinic keratosis is precursor
Actinic keratosis
Can progress to SCC
small, 3-10mm, sandpaper-like spots, on elderly, fair-skinned, sun sensitive areas
Tx: topical chemo (5-FU), photodynamic tx, topical immune modulator (Imiquimod), cautery & destruction, cryosurgery, cautery & curettage, shave excision, cosmetic resurfacing (dermabrasion/chemical peels)
MC type of collagen in a scar?
Type I
Collagen = principal structural protein in tissues
Made of 2 amino acids: hydroxyproline and hydroxylysine
Hydroxylation needs ascorbic acid, important for stabilization and cross-linking of collagen.
Type I collagen: predominant collagen in body, healed wounds, and scars
Type II: cartilage
Type III: blood vessels, fetal skin, uterus
Type IV: basement membrane
Type V: cornea
Fothergill’s sign
rectus sheath hematoma that remains unchanged with contraction of rectus muscles
palpable abdominal mass, most often below the umbilicus, noted in sitting or lying position that remains unchanged with contraction of rectus muscles (Fothergill’s sign)
Rectus sheath hematoma
Types of rectus sheath hematomas
I: hematoma is intramuscular, increase in size of muscle seen, ovoid or fusiform shape, unilateral, doesn’t dissect along fascial planes. Tx: d/c home
II: intramuscular but blood between muscle and transversals fascia, bilateral, blood in prevesical space. Tx: admit for obs
III: blood b/w transversals fascia and muscle, in peritoneum, and prevesical space. Tx: angioembolization
Decrease risk of SSI following ostomy closure by?
purse-string closure technique
avoids open wound, lowest wound infection rate
Merkel cell carcinoma
Arise from Merkel cells of epidermis and hair follicle
Lesions are raised, purple, subcutaneous nodukes
Histo: monomorphic cells, large pale nuclei, scant cytoplasm, whorled paranuclear plaques; +CK20, -TTF1
Radiation induced skin ulcer
sxs: pruritus, pain
hx of radiation
histo: epidermal atrophy, dermal sclerosis (eosinophilic homogenized sclerosis of dermal collagen), dilated superficial blood vessels, loss of adnexal structures (hair follicles, sweat ducts), increased atypical stellate-shaped fibroblasts
tx: conservative wound care (1st), aggressive radical excision w/ recon (2nd line)
Pressure injury staging
Stage I: intact skin, localized nonblanching erythema
Stage II: partial thickness skin loss, exposed dermis
Stage III: full-thickness skin loss, exposed fat and granulation tissue
Stage IV: full thickness skin and tissue loss, exposed fascia, muscle, tendon, cartilage, bone
Lymphangitis
Infection of superficial lymphatic vessels
MCC: group A strep (strep pyogenes)
Streaking erythema, warmth, tenderness, induration, lymphadenopathy, hx of trauma to affected area
Tx: I&D of entry wound, Abx
Basal cell carcinoma
excision w/ 0.5cm margins
pearly, rolled edges, pink/brown/black
Necrotizing fasciitis
Type 1: polymicrobial (MC)
Type 2: monomicrobial (Group A strep, Staph/MRSA)
Type 3: Trauma, marine (Clostridium, vibrio)
Type 4: Fungal (Candida)
High suspicion -> surgical exploration & debridement
Low suspicion -> Labs & imaging
MR/CTs are highly sensitive but not specific
XR showing subQ gas in ~30% of NSTIs
Dermatofibrosarcoma protuberans (DFSP)
Flesh colored mass
Dermal or subdermal tumor, no penetration into epidermis
Histo: proliferation of spindle-shaped tumor cells involving dermis and subcutaneous adipose tissue; tentacles extend laterally from the lesion
tx: en bloc excision w/ wide margin (2-4cm)
t(17;22)(q22;q13) translocation - fuses COL1A1 and PDGFB genes
Imatinib (PDGFB rec blocker) can downstage locally advanced tumor
+CD34, +vimentin
-Factor XIIIa, -alpha-smooth muscle actin
Strongest independent prognostic factor of soft tissue sarcomas, independent indicator of degree of malignancy, and probability of distant mets & death
histo grading
Soft tissue sarcoma
~80% originate from soft tissue, rest from bone
Dx: CNBx
Histo grading system:
1) Tumor differentiation
2) Mitotic count
3) Tumor necrosis
Grade 1 (<3), Grade 3 (>5)
Well-differentiated: liposarcoma, leiomyosarcoma
Poorly-differentiated: pleomorphic sarcomas, synovial sarcomas, osteosarcoma, PNET
Undifferentiated spindle cell tumor
MC location: prox tibia, distal metaphyses of femur
Radiography: loss of normal trabeculation, cortical destruction, adjacent soft tissue invasion, mass
Imaging of choice: MRI w/ contrast
Path: high-grade (>90%), fibroblasts, whirling pattern, multinucleated giant cells, inflammatory cells, foamy mononuclear giant cells
Tx: neoadjuvant chemo (relieve pain, decrease edema, contracture, size), urgent surgical resection w/ wide margins
Steps for skin graft healing
Imbibition -> inosculation -> revascularization
Imbibition: day 0-2, gets nutrients from plasma through direct contact
Inosculation: day 2-3, progressive anastomosis of transected vessels
Revascularization: new vessels from capillary bed
Tx of metastatic melanoma
If neg for anti-programmed cell death protein (PD1) & pos for BRAF -> ipilimumab (cytotoxic T-lymphocyte Ag-4 - CTLA-4; blocking antibody). humanized IgG1-kappa monoclonal Ab that competitively inhibits CTLA-4 negative regulatory checkpoint. Improves overall and progression-free survival.
Nivolumab: PD-1 inhibitor (good for metastatic melanoma with pos PD-1
Vemurafenib: used in unresectable melanomas with V600E mutations in BRAF gene
Temperature at which collagen uncoils
45C (113F)
Temp at which protein denaturation occurs, coagulation necrosis begins
60C (140F)
Temp at which carbonization begins, drying and shrinkage of tissue
80C (176F)
Temp at which cell vaporization and vacuoles form causing cell destruction
100C (212F)
Temp at which oxidation of protein/lipids -> carbon residue or eschar formation
125C (257F)
Familial BK Mole Syndrome mutation
p16, CDKN2A gene
Melanoma tumor markers
S-100+
HMB45
Tyrosinase
V600E
