Skin and SubQSkin and SubQBasic ScienceBasic Science

4/6/104/6/10Dr. Bennett Fontenot MD, PhD, JD, Dr. Bennett Fontenot MD, PhD, JD, RN, RD, DMD, DDS, NP, BS, esq, RN, RD, DMD, DDS, NP, BS, esq,

PAPA

AnatomyAnatomy► EpidermisEpidermis

Keratinocytes Keratinocytes ► stratum germinatum (basal), spinosum, granulosum, lucidum, stratum germinatum (basal), spinosum, granulosum, lucidum,

corneum. corneum. ► Lose mitotic ability – 40-56 daysLose mitotic ability – 40-56 days

Melanocytes Melanocytes ► derived from precursor cells of the neural crestderived from precursor cells of the neural crest► extend dendritic processes upward from basal cell extend dendritic processes upward from basal cell ► pigment is packaged into melanosomes and transported into the pigment is packaged into melanosomes and transported into the

epidermis via dendritic processes, phagocytized by keritinocyes epidermis via dendritic processes, phagocytized by keritinocyes ► Despite differences in skin tone, the density of melanocytes is Despite differences in skin tone, the density of melanocytes is

constant among individuals. constant among individuals. ► Rate of melanin production, transfer to keratinocytes, and Rate of melanin production, transfer to keratinocytes, and

melanosome degradation that determine the degree of skin melanosome degradation that determine the degree of skin pigmentation. pigmentation.

Langerhans' cells Langerhans' cells ► act as the skin's macrophages. act as the skin's macrophages. ► Express class II MHC antigens, and has antigen-presenting Express class II MHC antigens, and has antigen-presenting

capabilities capabilities

AnatomyAnatomy

►DermisDermis Collagen- constitutes 70% of dermal dry weight Collagen- constitutes 70% of dermal dry weight

and is responsible for its tensile strength.and is responsible for its tensile strength. the skin primarily contains type I collagenthe skin primarily contains type I collagen Fetal dermis and new wounds contains mostly Fetal dermis and new wounds contains mostly

type III (reticulin fibers) collagen type III (reticulin fibers) collagen Elastic fibers Elastic fibers Glycosaminoglycans complexesGlycosaminoglycans complexes

Cutaneous sensation Cutaneous sensation ►Meissner's, Ruffini's, and Pacini's corpuscles transmit Meissner's, Ruffini's, and Pacini's corpuscles transmit

information on local pressure, vibration, and touchinformation on local pressure, vibration, and touch

Anatomy Anatomy

► Three main adnexal structures:Three main adnexal structures: eccrine glands- sweat-producing eccrine glands eccrine glands- sweat-producing eccrine glands

are located over the entire body are located over the entire body pilosebaceous unitspilosebaceous units

►Hair folicles and sebaceous glandsHair folicles and sebaceous glands► reservoir of pluripotential stem cells critical in reservoir of pluripotential stem cells critical in

epidermal reproductivityepidermal reproductivity► In skin graft harvest, residual hair follicles supply new In skin graft harvest, residual hair follicles supply new

keratinocytes to regenerate the epidermis and restore keratinocytes to regenerate the epidermis and restore skin integrityskin integrity

apocrine glandsapocrine glands►primarily found in the axillae and anogenital regionprimarily found in the axillae and anogenital region►predispose both regions to suppurative hydroadenitispredispose both regions to suppurative hydroadenitis

Injuries Injuries

► Traumatic Traumatic Dog Bites- Dog Bites- Pasteurella multocidaPasteurella multocida – Augmentin – Augmentin Human Bites- Human Bites- Eikenella corrodensEikenella corrodens Dirty- allow to heal by secondary intention after Dirty- allow to heal by secondary intention after

debridement and irrigationdebridement and irrigation► CausticCaustic

Acid: Acid: ► coagulativecoagulative injury injury ► copious skin irrigation for at least 30 minutes with water copious skin irrigation for at least 30 minutes with water ► hydrofluoric acid - neutralized with calcium, hydrofluoric acid - neutralized with calcium,

Alkaline agents Alkaline agents ► liquefactiveliquefactive injury - a longer, more sustained period of injury injury - a longer, more sustained period of injury► iirrigation of the affected area with continuous water flow iirrigation of the affected area with continuous water flow

should be maintained for at least 2 hoursshould be maintained for at least 2 hours

Infections/Inflammatory Infections/Inflammatory DiseasesDiseases

Folliculitis, Furuncles, and Folliculitis, Furuncles, and Carbuncles Carbuncles

► Folliculitis is an infection of the hair follicle. Folliculitis is an infection of the hair follicle. ► Usually Usually StaphylococcusStaphylococcus, but gram-negative , but gram-negative

organisms may cause follicular inflammation organisms may cause follicular inflammation as well. as well.

► Furuncle (boil) begins as folliculitis, but may Furuncle (boil) begins as folliculitis, but may eventually progress to form a fluctuant eventually progress to form a fluctuant abscessabscess

► Carbuncle- more involved, deep-seated Carbuncle- more involved, deep-seated infections that result in multiple draining infections that result in multiple draining cutaneous sinuses are called carbuncles. cutaneous sinuses are called carbuncles.

► Furuncle/Carbuncle require I&D +/- ABXFuruncle/Carbuncle require I&D +/- ABX

Infections/Inflammatory Infections/Inflammatory DiseasesDiseases

Necrotizing fasciitisNecrotizing fasciitis► The most common sites are the external genitalia, perineum, The most common sites are the external genitalia, perineum,

or abdominal wall (or abdominal wall (Fournier gangreneFournier gangrene). ). ► Necrotizing fasciitis represents a rapid, extensive infection of Necrotizing fasciitis represents a rapid, extensive infection of

the fascia deep to the adipose tissue, without involvement of the fascia deep to the adipose tissue, without involvement of muscle. muscle.

► Necrotizing myositis primarily involves the muscles but Necrotizing myositis primarily involves the muscles but typically spreads to adjacent soft tissues. typically spreads to adjacent soft tissues.

► The most common organisms The most common organisms Group A streptococci, Group A streptococci, ClostridiumClostridium species species Gram-negative species- Gram-negative species- Escherichia coliEscherichia coli, , EnterobacterEnterobacter, ,

PseudomonasPseudomonas species, species, ► Clinical risk factors - diabetes mellitus, malnutrition, obesity, Clinical risk factors - diabetes mellitus, malnutrition, obesity,

steroid use, renal failure, cirrhosis.steroid use, renal failure, cirrhosis.► Management - broad-spectrum IV antibiotics, aggressive Management - broad-spectrum IV antibiotics, aggressive

surgical debridement.surgical debridement.

Infections/Inflammatory Infections/Inflammatory DiseasesDiseases

Hidradenitis SuppurativaHidradenitis Suppurativa

►Defect of the terminal follicular epithelium.Defect of the terminal follicular epithelium.► Apocrine gland blockage, obstructed infection Apocrine gland blockage, obstructed infection

leads to abscess formation throughout leads to abscess formation throughout affected axillary, inguinal, and perianal affected axillary, inguinal, and perianal regions. regions.

► Foul-smelling sinuses Foul-smelling sinuses ► Treatment Treatment

Acute infections- application of warm compresses, Acute infections- application of warm compresses, antibiotics, and open drainage. antibiotics, and open drainage.

Chronic hidradenitis- wide excision is required and Chronic hidradenitis- wide excision is required and closure may be achieved via skin graft or local flap closure may be achieved via skin graft or local flap placementplacement

Benign Tumors Benign Tumors

► Cysts Cysts Epidermal cysts- most common type, may present as a Epidermal cysts- most common type, may present as a

single, firm nodule anywhere on the body. single, firm nodule anywhere on the body. Dermoid cysts- are congenital lesions that result when Dermoid cysts- are congenital lesions that result when

epithelium is trapped during fetal midlineepithelium is trapped during fetal midline Trichilemmal (pilar) cysts- most often on the scalp of Trichilemmal (pilar) cysts- most often on the scalp of

females. When ruptured, these cysts have an intense, females. When ruptured, these cysts have an intense, characteristic odor.characteristic odor.

Difficult to distinguish one type of cyst from another: Each Difficult to distinguish one type of cyst from another: Each cyst presents as a subcutaneous, thin-walled nodule cyst presents as a subcutaneous, thin-walled nodule containing keratincontaining keratin

If infected- tx with I&D, must remove all of cyst wall to If infected- tx with I&D, must remove all of cyst wall to prevent recurrenceprevent recurrence

► Acrochordons, Dermatofibromas, Lipomas Acrochordons, Dermatofibromas, Lipomas

MALIGNANT TUMORSMALIGNANT TUMORS

►Basal Cell Carcinoma Basal Cell Carcinoma the most common type of skin cancer the most common type of skin cancer Waxy and cream colored, present with rolled, Waxy and cream colored, present with rolled,

pearly borders surrounding a central ulcer. pearly borders surrounding a central ulcer. Slow growing, and metastasis is extremely rareSlow growing, and metastasis is extremely rare Extensive local tissue destruction is commonExtensive local tissue destruction is common Treament: Treament:

►Surgical excision with 0.5-cm to 1-cm margins.Surgical excision with 0.5-cm to 1-cm margins.►Tumors located on the cheek, nose, or lip, may be Tumors located on the cheek, nose, or lip, may be

best approached with Mohs' surgerybest approached with Mohs' surgery

MALIGNANT TUMORSMALIGNANT TUMORS► Squamous Cell CarcinomaSquamous Cell Carcinoma

Arise from epidermal keratinocytes Arise from epidermal keratinocytes increased invasiveness and tendency to metastasize.increased invasiveness and tendency to metastasize. Before local invasion, in situ SCC lesions are termed Before local invasion, in situ SCC lesions are termed Bowen's Bowen's

diseasedisease. . In situ SCC tumors specific to the penis are referred to as In situ SCC tumors specific to the penis are referred to as

erythroplasia of Queyraterythroplasia of Queyrat Lesions arising in burn scars (Marjolin's ulcer), areas of chronic Lesions arising in burn scars (Marjolin's ulcer), areas of chronic

osteomyelitis, and areas of previous injury metastasize earlyosteomyelitis, and areas of previous injury metastasize early Treament: Treament:

► Surgical excision with 1-cm margins.Surgical excision with 1-cm margins.► Tumors located on the cheek, nose, or lip, may be approached with Mohs' Tumors located on the cheek, nose, or lip, may be approached with Mohs'

surgerysurgery The need for lymph node (LN) dissection remains a topic of debate. The need for lymph node (LN) dissection remains a topic of debate.

► Regional LN excision is indicated for clinically palpable nodesRegional LN excision is indicated for clinically palpable nodes► lesions arising in chronic wounds are more aggressive- prophylactic LN lesions arising in chronic wounds are more aggressive- prophylactic LN

dissection is indicated. dissection is indicated. Metastatic disease is a poor prognostic sign, and only 13% of patients Metastatic disease is a poor prognostic sign, and only 13% of patients

typically survive 10 years.typically survive 10 years.

APCAPC Gene and Familial Gene and Familial Adenomatous Polyposis Adenomatous Polyposis

► Hundreds to thousands of polyps in the colon and Hundreds to thousands of polyps in the colon and rectum. The polyps usually appear in adolescence and, rectum. The polyps usually appear in adolescence and, if left untreated, progress to colorectal cancer. if left untreated, progress to colorectal cancer.

► FAP is associated with benign extracolonic FAP is associated with benign extracolonic manifestationsmanifestations congenital hypertrophy congenital hypertrophy retinal pigment epitheliumretinal pigment epithelium epidermoid cysts, and osteomas.epidermoid cysts, and osteomas.

► Also at risk forAlso at risk for upper intestinal neoplasms (upper intestinal neoplasms (gastric and duodenal polyps, gastric and duodenal polyps,

duodenal and periampullary cancerduodenal and periampullary cancer), ), hepatobiliary tumors (hepatoblastoma, pancreatic cancer, and hepatobiliary tumors (hepatoblastoma, pancreatic cancer, and

cholangiocarcinoma),cholangiocarcinoma), thyroid carcinomas, desmoid tumors, and medulloblastomas. thyroid carcinomas, desmoid tumors, and medulloblastomas.

► Gardner’s and Turcot’sGardner’s and Turcot’s

Mismatch Repair Genes and Mismatch Repair Genes and Hereditary Nonpolyposis Hereditary Nonpolyposis

Colorectal Cancer (HNPCC) Colorectal Cancer (HNPCC) ► Autosomal dominant hereditary cancer Autosomal dominant hereditary cancer

syndrome that predisposes to a wide spectrum syndrome that predisposes to a wide spectrum of cancers, including colorectal cancer without of cancers, including colorectal cancer without polyposis. polyposis.

► HNPCC consists of at least two syndromes: HNPCC consists of at least two syndromes: Lynch syndrome 1- colorectal cancer with early ageLynch syndrome 1- colorectal cancer with early age Lynch syndrome 2- colorectal cancer + carcinoma of Lynch syndrome 2- colorectal cancer + carcinoma of

the endometrium, transitional cell carcinoma of the the endometrium, transitional cell carcinoma of the ureter and renal pelvis, and carcinomas of the ureter and renal pelvis, and carcinomas of the stomach, small bowel, ovary, and pancreas.stomach, small bowel, ovary, and pancreas.

► Amsterdam Criteria Amsterdam Criteria

The MelanomaThe Melanoma► Superficial spreading, Superficial spreading,

Most common- accounts for up to 70% of melanomas. Most common- accounts for up to 70% of melanomas. typically flat and measure 1 to 2 cm in diameter at diagnosis.typically flat and measure 1 to 2 cm in diameter at diagnosis. Before vertical extension, a prolonged radial growth phase is Before vertical extension, a prolonged radial growth phase is

characteristic characteristic ► Nodular type Nodular type

accounts for 15 to 30% of melanomas.accounts for 15 to 30% of melanomas. lack of radial growth; all are in the vertical growth phase at lack of radial growth; all are in the vertical growth phase at

diagnosis. diagnosis. ► Lentigo maligna Lentigo maligna

accounts for 4 to 15% of melanomas, accounts for 4 to 15% of melanomas, most frequently on the neck, face, and hands of the most frequently on the neck, face, and hands of the best prognosis because invasive growth occurs late. best prognosis because invasive growth occurs late.

► Acral lentiginous Acral lentiginous least common subtype, and constitutes only 2 to 8% least common subtype, and constitutes only 2 to 8% 29 to 72% of all melanomas in dark-skinned people 29 to 72% of all melanomas in dark-skinned people on the palms, soles, and subungual regions. on the palms, soles, and subungual regions.

PrognosisPrognosis

► Prognosis is based on Prognosis is based on Depth of InvasionDepth of Invasion► Presence of ulceration confers a worse Presence of ulceration confers a worse

prognosis for same depth of invasionprognosis for same depth of invasion►Nodular melanomas have the same Nodular melanomas have the same

prognosis as superficial spreading types prognosis as superficial spreading types when lesions are matched for depth of when lesions are matched for depth of invasion.invasion.

► Lentigo maligna has a better prognosis even Lentigo maligna has a better prognosis even after correcting for thickness, and acral after correcting for thickness, and acral lentiginous has a worse prognosis lentiginous has a worse prognosis

Breslow ThicknessBreslow Thickness

DiagnosisDiagnosis

►Requires excisional biopsy or incisional Requires excisional biopsy or incisional BxBx

NodesNodes

NodesNodes

► All microscopically or clinically positive LNs All microscopically or clinically positive LNs should be removed by regional nodal should be removed by regional nodal dissection.dissection.

► When groin LNs are removed, the deep (iliac) When groin LNs are removed, the deep (iliac) nodes must be removed along with the nodes must be removed along with the superficial (inguinal) nodes, superficial (inguinal) nodes,

► For axillary dissections, the nodes medial to the For axillary dissections, the nodes medial to the pectoralis minor muscle also must be resected.pectoralis minor muscle also must be resected.

► For lesions on the face, anterior scalp, and ear, For lesions on the face, anterior scalp, and ear, a superficial parotidectomy to remove parotid a superficial parotidectomy to remove parotid nodes and a modified neck dissection is nodes and a modified neck dissection is recommended.recommended.

Mets Mets

►Once melanoma has spread to a distant site, Once melanoma has spread to a distant site, median survival is 7 to 8 months median survival is 7 to 8 months

► 5-year survival rate is less than 5%.5-year survival rate is less than 5%.► Solitary lesions in the brain, GI tract, or skin Solitary lesions in the brain, GI tract, or skin

that are symptomatic should be excised that are symptomatic should be excised when possible. when possible.

► Use of radiation therapy, regional and Use of radiation therapy, regional and systemic chemotherapy, and systemic chemotherapy, and immunotherapy are all under investigation – immunotherapy are all under investigation – interferon alphainterferon alpha