Plastics, Skin and Soft Tissues Flashcards
Epidermis
primarily cellular
Keratinocytes
main cell type in epidermis; originate from basal layer; provide mechanical barrier
melanocytes
neuroectodermal origin (neural crest cells); in basal layer of epidermis
- have dendritic processes that transfer melanin to neighboring keratinocytes via melanosomes
- density of melanocytes is the same among races; difference is in production
Dermis
primarily structural proteins for the epidermis
Langerhans cells
act as antigen presenting cells (MHC class II)
- originate from bone marrow
- have a role in contact hypersensitivity reactions (type IV)
Pacinian corpuscles
pressure
Ruffini’s endings
warmth
Krause’s end bulbs
cold
Meissner’s corpuscles
tactile sense
Eccrine sweat glands
aqueous sweat (thermal regulation, usually hypotonic)
Apocrine sweat glands
milky sweat
*highest concentration of glands in palms and soles; most sweat is the result of sympathetic nervous system via acetylcholine
Lipid soluble drugs
increase skin absorption
type I collagen
predominant type; 70% weight of dermis; gives tensile strength
Tension
resistance to stretching (collagen)
Elasticity
ability to regain shape (branching proteins that can stretch to 2X normal length)
Cushing’s striae
caused by loss of tensile strength and elasticity
Split thickness skin grafts
include all of the epidermis and part of the dermis
- donor site skin regenerated from hair follicles and skin edges on split-thickness grafts
- more likely to survive; graft not as thick so easier fro imbibition and subsequent revascularization to occur
Full thickness skin grafts
have less wound contraction; good for areas such as palms and back of hands
imbibition
osmotic; blood supply to skin graft for days 0-3
neovascularization
starts around day 3
*poorly vascularized beds are unlikely to support skin grafting (tendon, bone without periosteum, XRT areas)
Pedicled or anastomosed free flap necrosis
venous thrombosis most common cause Ti
Tissue expansion
occurs by local recruitment, thinning of dermis and epidermis, mitosis
TRAM flaps complications
flap necrosis, ventral hernia, bleeding, infection, abdominal wall weakness
- rely on superior epigastric vessels
- periumbilical perforators most important determinant of TRAM flap viability
- transverse rectus abdominus myocutaneous flap
Pressure sores
stage I - erythema and pain, no skin loss
stage II - partial skin loss with yellow debris
stage III - full thickness skin loss, subcutaneous tissue exposure
stage IV - usually involves bony cortex
UV radiation
damages DNA and repair mechanisms
- both an promoter and initiator
- melanin single best factor for protecting skin from UV radiation
- UV-B - responsible for chronic sun damage
Melanoma
- represents only 3% - 5% of skin CA but accounts for 65% of the deaths
- Risk factors for melanoma
- dysplastic, atypical or large congenital nevi (10% lifetime risk for melanoma)
- Familial BK mole syndrome (almost 100% risk of melanoma)
- xeroderma pigmentosum
- fair complexion, easy sunburn, intermittent sunburns, previous skin CA, previous XRT
- 10% familial
- most common melanoma site on skin - back in men, legs in women
- Prognosis worse for men, ulcerated lesions, ocular and mucosal lesions
- Signs of transformation - color change, angulations, indentation / notching, enlargement, darkening, bleeding, ulceration
- originates from neural crest cells (melanocytes) in basal layer epidermis
- blue color - most ominous
- Dx:
- < 2cm lesion –> excisional biopsy unless cosmetically sensitive area; need resection with margins if pathology comes back as melanoma
- > 2 cm lesions or cosmetically sensitive area –> incisional biopsy (or punch biopsy), will need to resect with margins if pathology shows melanoma
Most common location for distant melanoma mets
Lung
Most common metastasis to small bowel
melanoma
Lentigo maligna
least aggressive, minimal invasion, radial growth 1st usual; elevated nodules
Superficial spreading melanoma
most common; intermediate malignancy; originates from nevus/sun-exposed areas
Nodular melanoma
most aggressive; most likely to have metastasized at time of dx; deepest growth at time of dx; vertical growth 1st; bluish black with smooth borders; occurs anywhere on the body
Acral lentiginous
very aggressive; palms/soles of African Americans
Melanoma in situ or thin lentigo maligna
0.5 cm margins OK
Melanoma staging
need chest xray, LFTs; examine all possible draining lymph nodes
Nodes (melanoma)
always need to resect clinically positive nodes with melanoma
- perform SLN biopsy if nodes clinically negative and tumor > 0.9 mm deep
- involved nodes usually nontender, round, hard 1-2cm
- all stage III tumors need full LN dissection
- need to include superficial parotidectomy for anterior head and neck melanomas
Axillary node melanoma with no other primary
complete axillary node dissection
resection of melanoma mets
has provided some patients with long disease-free interval and is the best chance for cure
*isolated mets (i.e., lung or liver) that can be resected with low risk procedure should probably undergo resection
Clarks Levels for Melanoma
I - epidermis basement membrane intact
II - papillary dermis through basement membrane
III - junctional dermis between papillary and reticular dermis
IV - reticular dermis
V - fat
Melanoma margins
Depth Margin Needed
< 1mm 2 cm
1-4 mm 2 cm
> 4 mm 2-3 cm
Basal Cell Carcinoma
- most common malignancy in US; 4X more common than squamous cell skin CA
- 80% on head and neck
- originates from epidermis - basal epithelial cells and hair follicles
- pearly appearance, rolled borders
- pathology - peripheral palisading of nuclei and stromal retraction
- slow, indolent growth
- ulcerative, rare metastases, deep invasion, occasionally dark
- regional adenectomy for clinically positive nodes
- morpheaform type - most aggressive, has collagenase production
- tx: 0.3 - 0.5 cm margins
- XRT and chemo - may be limited benefit for inoperable disease or mets; neuro, lymphatic, or vessels invasion
Squamous Cell Carcinoma
- overlying erythema, papulonodular with crust and ulceration
- may have surrounding induration and satellite nodules
- usually red-brown; can have pearly appearance
- mets more frequently than basal cell CA but less common than melanoma
- can develop in postradiation areas or in old burn scars
- Risk factors: actinic keratoses, xeroderma pigmentosum, Bowen’s disease, atrophic epidermis, arsenics, hydrocarbons (coal tar), chlorophenols, nitrates, HPV, immunosuppression, sun exposure, fair skin, XRT exposure, previous skin CA
- Risk factors for mets: poorly differentiated, greater depth, recurrent lesions, immunosuppression
- Tx: 0.5-1.0 cm margins for low risk
- can treat high risk with Mohs surgery (margin mapping using conservative slices; not used for melanoma) when trying to minimize area of resection
- regional adenectomy for clinically positive nodes
- XRT and chemotherapy - may be of limited benefit for inoperable disease or mets; neuro, lymphatic or vessels invasion
Most common soft tissue sarcoma
#1 malignant fibrous histiosarcoma #2 liposarcoma
Soft tissue sarcomas
50% arise from extremities; 50% in children (arise from embryonic mesoderm)
- most sarcomas are large, grow rapidly and are painless
- asymptomatic mass most common presentation, GI bleeding, bowel obstruction, neuro deficit
- CXR to r/o lung mets
- MRI before biopsy to r/o vascular, neuro, or bone invasion
- hematogenous spread, not to lymphatics; mets to nodes is rare
- lung most common site for metastasis
- staging based on grade, not size or nodes
- tx: want at least 3 cm margins and at least one uninvolved fascial plane
- place clips to mark site of likely recurrence; will XRT these later
- post op XRT for high grade tumors, close margins, or tumors > 5 cm
- chemo is doxorubicin based
- tumors > 10 cm may benefit from preop XRT and chemo
- midline incision favored for pelvic and RP sarcomas
- 40% 5YSR with complete resection
Biopsy soft tissue mass
excisional biopsy if mass < 4cm
longitudinal incisional biopsy for masses > 4 cm
Head and neck sarcomas
can occur in peds (usually rhabdomyosardcoma)
Sarcoma risk factors
Asbestos - mesothelioma
PVC and Arsenic - angiosarcoma
Chronic lymphedema - lymphangiosarcoma
Kaposi’s sarcoma
vascular sarcoma
- can involve skin, mucous membranes or GI tract
- assoc with immunocompromised state
- rarely a cause of death in AIDS; 15-20 year survival; slow growing
- tx: XRT or intralesional vinblastine for local disease; systemic chemotherapy for disseminated disease; surgery for intestinal hemorrhage
Childhodd rhabdomyosarcoma
- # 1 soft tissue sarcoma in kids
- head/neck, GU, extremities and trunk (poorest prognosis)
- Embryonal - most common
- Alveolar - worst prognosis
- Tx: surgery; doxorubicin based chemotherapy
Bone sarcomas
- most are metastatic at time of dx
- osteosarcoma –> increased incidence around the knee; originates from metaphyseal cells; usually in children
- usually need to take the joint, followed by reconstruction; may require amputation
Neurofibromatosis
CNS tumors, peripheral sheath tumors, pheochromocytoma
Li-Fraumeni syndrome
childhood rhabdomyosarcoma, many others
Hereditary retinoblastoma
also includes other sarcoma
Tuberous sclerosis
angiomyolipoma
Gardner’s syndrome
familial adenomatous polyposis and intra-abdominal desmoids
Xanthoma
yellow, contains histiocytes; tx: excision
Actinic keratosis
premalignant, in sun damaged areas, need excisional biopsy if suspicious
Seborrheic keratosis
not premalignant; trunk on elderly; can be dark
Arsenical keratosis
associated with squamous cell carcinoma
Merkel cell carcinoma
neuroendocrine
- aggressive regional and systemic spread; patients have red to purple papulonodule / indurated plaque
- have neuron-specific enolase (NSE), cytokeratin, and neurofilament protein
Glomus cell tumor
painful tumor composed of blood vessels and nerves
- benign, most common in terminal aspect of digit
- tx: tumor excision
Hutchinson’s freckle
in elderly, often on face; premalignant, not aggressive
Lip laceration
important to line up vermillion border
desmoid tumors
usually benign; occur in fascial planes
- anterior abdominal wall (most common location)
- high risk of local recurrences; no distant spread
- tx: surgery or chemotherapy / XRT if vital structure involved
Bowen’s disease
SCCA in situ; 10% turn into invasive SCCA
tx: excision with negative margins usual
Keratoacanthoma
rapid growth, rolled edges, crater filled with keratin
- is not malignant but can be confused with SCCA
- involutes spontaneously over months
- always biopsy these to be sure
- if small, excise; if large, biopsy and observe
Hyperhydrosis
increase sweating, especially noticeable in palms; tx: sympathectomy if refractory
Hidradenitis
infection of apocrine sweat glands, usually in axilla and groin regions
- staph / strep most common organisms
- tx: antibiotics, improved hygiene 1st; may need surgery
Epidermal inclusion cyst
most common; have completely mature epidermis with creamy keratin material
Trichilemmal cyst
in scalp; no epidermis
ganglion cyst
over tendons; usually over wrists; filled with collagenous material
dermoid cyst
midline abdominal and sacral lesions, occiput and nose; found along body fusion planes
pilonidal cyst
congenital coccygeal sinus with ingrown hair; gets infected and need to be excided
keloids
autosomal dominant; dark skin
- collagen goes beyond original scar
- tx: XRT, steroids, silicone, pressure garments
Hypertrophic scar tissue
dark skin; flexor surfaces of upper torso
- collagen stays within confines of scar
- often occurs in burns or wounds that take long time to heal
- tx: steroids, silicone, pressure garments
