lecture ix skin and subcutaneous tissue

8/13/2019 Lecture Ix Skin and Subcutaneous Tissue

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SKIN AND SUBCUTANEOUS

TISSUE


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I. Introduction

A. Function

1. Protection

2. Thermoregulation

3. Sensory


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B. Anatomy

1. Epidermismost cellular layer

a. keratinocytesmost numerousand forms a mechanical barrier

b.Langerhans immunologic

function

c. Melanocytespigment


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2. Dermissupporting layer, mostlyfibroblast which produce collagen

3. Basement layerdermal epidermaljunction

- first layer where blood vessel and

lymphatics are present- if lesion has not crossed this layer, it iscalled an in-situ lesion


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II. Pathology

A. Trauma

1. Dirty and infected woundsdebridement and closed by secondaryintention

2. Lacerationsclosed primarily


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LACERATIONS


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B. Decubitus Ulcer or Pressure Ulcer

- excessive, unrelieved pressure (60 cmHg applied for 1 hour)

- muscle more sensitive than skin to

ischemia- Tx.debridement and grafting


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DECUBITUS ULCER


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C. Keloid and Hypetrophic Scar

- over abundance of deposition of collagen

1. Hypertrophic scarnodularity remains within theincision

- no treatment necessary

2. Keloidnodularity goes beyond the incision- seen more in children and across sternum

- treated with triamcinolone


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KELOID


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D. Infections

1. Folliculitisinfectedhair follicle- caused by Staph. sp.

- leads to furuncle carbuncle

- Tx.incision and

drainage andantibiotics

2. Hidradenitis suppuritiva

- plugged apocrine gland

in axilla and inguinalarea

- Tx.warm compress,hygiene, discontinuationof deodorants, opendrainage if recurrent


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3. Pilonidal diseaseinfected

pilosebaceous cysts in thesaccrococygeal area, lined bygranulation tissue

- Tx.drainage, currete


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4. Staphyloccocal Scalded Skin Syndrome

- erythema, bullae formation, loss ofepidermis

- caused by exotoxin from staphyloccocalinfection

- similar to partial thickness burn

-cleavage is in the granular layer- Tx.replace fluid, electrolytes, skin care,

antibiotics


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STAPHYLOCOCCAL SCALDED SKINSYNDROME


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5. Toxic Epidermal Necrolysis- Immunologic reaction to

certain drugs such assulfonamides, phenytoin,

barbituates, and tetracycline- Tx.same as SSSS

6. Viralverruca vulgaris,

associated with pappiloma virus- associated with squamous cellca- Tx.chemical, electrocautery,surgery


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E. Benign TumorsCysts

1. epidermalsebaceous cysts,most common

2. Trichilemmal

occurs morecommonly in females

3. Dermoidresultsfrom epithelium

trapped duringmidline closure infetal development- Tx. - excision


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F. Nevi

1. Acquired

a. Junctionalepidermis

b. Compoundmigrates partially

down to the dermis

c. Dermalcells at dermal layer

- involutes


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ACQUIRED NEVI


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2. Congenitalrare

- large and may contain hair

- occurs in bathing trunks distribution

- Tx. - excision


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CONGENITAL NEVI


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G. Vascular1. Hemangioma

a. capillary(strawberry)

- compressible, vascularlesion with sharp borders

- located mostly in theface, scalp, and shoulder- observe, 90% involute


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b. Cavernous- bright red or purple, with spongyconsistency

- Tx.excision

2. Vascular malformation- enlarged vascular spaces lined with nonproliferating endothelial cells

a. portwine staincapillary malformation- Tx.embolization

b. glomus tumorpainful bluegray nodules

- arises from the glomus body or Sucquet- Hoyer canal found in the dermis andcontributes to thermal regulation- may lead to glomangiosarcoma- Tx. - excision


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GLOMUS TUMOR


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H. Soft Tissue Tumors( achrocordons,lipomas,dermatofibromas)

- Tx.excision

I. Neural

- Neurofibromas

(caf-au-lait spots)- associated with vonReklinghausensdisease


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J. Malignant Tumors

1. Epidemiology

a. malignant radiationb. chemicals

c. viral

d. chronic irritation

e. immunosuppresion


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2. Types

a. basal cell carcinoma- most common

- slow growing, rare metastases

- excision with 2-4 mm margin


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BASAL CELL CARCINOM


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b. squamous cell carcinoma- metastasizes faster- Bowens disease ca-in-situ

- Erythroplasia of Queyratca ofthe penis- lesion more than 1 cm has 50%chance of metastasis

- Tx.excision with 1 cm margin- Mohs technique serial excision topreserve skin


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SQUAMOUS CELL CARCINOMA


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ERYTHROPLASI OF QUEYRAT


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c. malignant melanoma

- arises from dysplastic

melanocytes

i. superficial spreading

- most common (70%)

- flat with areas of regression


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ii. nodular15-20%

- dark, slightly raised

- growth more vertical thanradial

iii. lentigo malignant 5-10%

- best prognosis- occurs in areas of high solardegeneration


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MELANOMA


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b. prognostication

i. Clark

ii. Breslowiii other factors

- anatomic location

extremities better than trunkor face

- ulceration


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- inflammatory infitrates- sex

- histologic type

c. treatment- still primarily surgical

i. in-situ - .5 to 1 cm marginii. T1 (smaller than .76 mm)- 1-2 cmiii. thicker lesion3 cm margin- excision is up to the deep fascia

- chemotherapy- palpable nodes are removed by regionaldissection

lecture ix skin and subcutaneous tissue

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