Chapter 18 - Plastics Flashcards
What are the main types of cells in the epidermis
Keratinocytes. Originate from basal layer; provide mechanical barrier
Where do the melanocytes originate from?
Neuroectodermal origin; in basal layer of epidermis.
Have dendritic processes that transfer melanin to neighboring keratinocytes via melanosomes
What are langerhan cells, and where are they?
in the dermis. Act as antigen presenting cells. They originate from bone marrow. They have a role in contact hypersensitivity reactions (type IV)
These are pressure sensory nerves
Pacinian corpuscles
What are the warmth sensory nerves
Ruffini’s endings
What are the cold sensory nerves?
Krause’s and bulbs
What are the tactile sensation sensory nerves?
Meissner’s corpuscles
What do Eccrine sweat glands do?
- Produce aqueous sweat
- Used for thermal regulation
- Usually produce hypotonic sweat
What do apocrine sweat glands do?
- Produce milky sweat
- Highest concentration of glands in palms and soles
- Most sweat is the result of sympathetic nervous system via acetylcholine
What is the most predominant type of collagen in the dermis?
Type one collagen. 70% of the weight of dermis; gives tensile strength
What are Cushing’s striae caused by?
Loss of tensile strength and elasticity
What is the donor site of a split thickness skin graft regenerated from?
Hair follicles and skin edges
How is a split thickness skin graft supported for the first three days
imbibition, osmotic blood supply
When does neovascularization of a split thickness skin graft begin?
Starts at day three. Tendon, bone without periosteum, XRT areas are unlikely to support graft
What is the most common cause of pedicled or free flap necrosis?
Venous thrombosis
What are the complications of a tram flap?
Flap necrosis, ventral hernia, bleeding, infection, abdominal wall weakness
How does UV radiation cause damage?
- Damages DNA and repair mechanisms
- It is both a promoter and an initiator
- Melanin is the single best factor for protecting skin from UV radiation
- UVB is responsible for chronic sun damage
What percentage of skin cancers melanoma?
3 to 5% of skin cancer but accounts for 65% of deaths
What are some genetic 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
What percentage of melanomas are familial?
10%
What is the most common melanoma site on skin?
Back in men, legs in women
What are signs of poor prognosis in melanoma
Color change, angulation, indentation/notching, enlargement, darkening, bleeding, ulceration
How do you go about diagnosing suspicious lesions for melanoma?
- Less than 2 cm lesion (or core needle) - excisional biopsy unless a cosmetically sensitive area
- Greater than 2 cm lesions or cosmetically sensitive areas - incisional biopsy (or punch)
- Need resection with margins if pathology comes back Melanoma
What is lentigo maligna melanoma? Is it aggressive? How does it behave?
- Least aggressive melanoma, minimal invasion, radial growth first
- Elevated nodules
What is superficial spreading melanoma?
Most common, intermediate malignancy; originates from Nevus/sun exposed areas
What is nodular melanoma?
Most aggressive; most likely to have metastasized at time of diagnosis; Deepest growth at time of diagnosis; vertical growth first; bluish black with smooth borders; occurs anywhere on the body
What is accral lentiginous melanoma?
Very aggressive; palms/soles of African-Americans
What do you do with melanoma in situ or thin lentigo maligna?
0.5 cm margins okay
What do you do with nodes in melanoma?
- Always resect clinically positive nodes in melanoma
- Perform SLNBx if nodes clinically negative and tumor greater than 1 mm deep
- Involved nodes often nontender, round, hard, 1.5 cm
- Need to include superficial parotidectomy for anterior head and neck melanomas
What do you do with axillary node melanoma with no other primary?
Complete axillary node dissection
Do you resect the metastases of melanoma?
Yes, can provide some patients with long disease free interval and is best chance for cure
Basal cell carcinoma?
- epidemiology
- location
- appearance
- path
- Most common malignancy in US; 4X more common than squamous cell carcinoma
- 80% on Head/neck
- Pearly appearance, rolled borders
- Pathology shows peripheral palisading of nuclei and stromal retraction
- Morpheaform type most aggressive; has collagenase production
Squamous cell carcinoma? Appearance? More/less frequent metastasis?
- Overlying erythema
- Papulonodular w/ crust and ulceration
- Usually red-brown; can also be Pearly
- Metastasize more frequently than basal cell carcinoma but less than melanoma
What are some characteristics of soft tissue sarcoma?
- Most common soft tissue sarcoma: malignant fibrous histiosarcoma, then liposarcoma
- 50% extremities
- 50% in children (from embryonic mesoderm)
- Present with asymptomatic mass, G.I. bleeding, bowel obstruction, neurologic deficit
- Need CXR to rule out lung mets
- MRI to rule out vascular, neuro, bone invasion (before biopsy)
- Biopsy
How do you biopsy soft tissue sarcoma?
- Core needle biopsy is best
- Excisional biopsy if mass < 4 cm
- Longitudinal incision biopsy for masses > 4 cm
- Hematogenous spread, not to lymphatics
- Lung most common site for metastasis
- Biopsy site must be excised if pathx is sarcoma
How do you stage soft tissue sarcomas?
- Based on grade, not size or nodes
- Grade is most important prognostic factor
- Undifferentiated gives worst prognosis
Characteristics of head and neck sarcomas?
- Can be in kids
- Usually rhabdomyosarcoma
- Hard to get negative margins
What is the most common pathx of visceral and retroperitoneal sarcomas?
What is the most important prognostic factor?
- Most commonly leiomyosarcoma and liposarcomas
- Ability to completely remove the tumor is the most important prognostic factor
PVC and arsenic exposure increase risk for what?
Angiosarcoma
Chronic lymphedema is associated with what sarcoma?
Lymphangiosarcoma
What is Kaposi’s sarcoma?
- Vascular sarcoma
- Can involve skin, mucous membranes, G.I. tract
- Treat with XRT or intralesional vinblastine
Childhood rhabdomyosarcoma?
- Number one soft tissue sarcoma in kids
- Head/neck, GU, ext, trunk (worst prognosis)
- Embryonal subtype is most common
- Alveolar subtype worse prognosis
- Surgery; doxorubicin-based chemotherapy
Bone sarcoma characteristics?
- Most are metastatic at diagnosis
- Osteosarcoma-increased incidence around the knee, originates from metaphyseal cells
- Need to take the joint followed by reconstruction
What soft tissue tumors are caused by neurofibromatosis?
- CNS tumors
- Peripheral sheath tumors
- Pheochromocytoma
What soft tissue tumors are caused by Li-fraumeni syndrome?
Childhood rhabdomyosarcoma and many others
What soft tissue tumors are caused by tuberous sclerosis?
Angiomyolipoma
What do xanthomas look like, what do they contain, how do you treat them?
Yellow in appearance, contain histiocytes, excise
What is actinic keratosis?
Premalignant, found in sun damaged areas; need excisional biopsy if suspicious
What is arsenical keratosis associated with?
squamous cell carcinoma
What are Merkel cell carcinomas?
- Neuroendocrine in nature
- Aggressive
- Red to purple papular nodule and indurated plaque
- Have neuron specific in enolase, cytokeratin, and neurofilament protein
What is a glomus cell tumor?
Painful tumor composed of blood vessels and nerves
Benign, most common in the terminal aspect of the digit
What is a Hutchinsons freckle?
Found in the elderly on the face, premalignant, not aggressive
What are desmoid tumors?
- Usually benign; occur in facial planes
- Anterior abdominal wall can occur during or after pregnancy, trauma, or surgery
- Intra-abdominal associated with Gardner syndrome and retroperitoneal fibrosis
What is the most common location for melanoma metastasis?
Lung
SCC management of high risk lesions (large, poorly differentiated, perineural differentiation)? Alternative treatments?
Surgical excision.
If do not wish surgery or poor candidate - cryotherapy, electrosurgery, radiation therapy.
What do melanomas stain for on pathology?
S-100 and HMB-45 proteins
How do you treat soft tissue sarcomas?
- Resect w/ 2-3 margins & 1 uninvolved fascial plane
- Postop XRT for high grade, close margins, >5 cm
- Chemotherapy is doxorubicin-based (Adriamycin)
- If >10 cm, preop chemo-XRT may be limb-sparing
- Resect isolated metastasis without evidence of systemic disease
- Poor prognosis, 40% five-year survival rate with complete resection
