dermal midterm

• Endoderm


  Produces digestive system, liver, pancreas, posterior tongue and lungs
• Ectoderm


  Produces hair, nails, skin, lips, gums, palate anterior ⅔ of tongue and nervous system
• Mesoderm


  Produces circulatory system, lungs, skeletal system and muscular system
• Pemphigus and pemphigoid treatment


  Rituximab therapy targeting B cell differentiation Ag CD20 and suppressing T cells
• Autoantibodies in pemphigus and pemphigoid


  DSG-3 for oral cavity, DSG-1 for skin
• Lichen planus


  Not autoimmune, presents with apoptotic keratinocytes, saw-tooth rete ridges, hyperkeratosis
• Mucous membrane pemphigoid


  Autoantibodies against basement membrane components, more common in females than males, 2x more common than pemphigus vulgaris
• Basal cell carcinoma


  Presents as crusted plaque with central concavity, branching capillaries, associated with odontogenic keratocysts and PTCH gene mutation
• Melanoma


  Characterized by ABCDE criteria, can occur de novo or from dysplastic nevus, prognosis depends on depth of invasion into dermis
• Erythema multiforme


  Type IV hypersensitivity reaction damaging basal epithelial cells, can present with targetoid lesions or major hemorrhagic crusting
• The hypodermis or subcutaneous tissue lies beneath the dermis and consists of loose connective tissue containing adipose cells (fat).
• The dermis contains blood vessels, nerves, hair follicles, sweat glands, sebaceous glands, and collagen fibers that give it strength and elasticity.
• The epidermis is the outermost layer of skin, composed of stratified squamous epithelium.
• Squamous cell carcinoma is characterized by an exophytic mass that may ulcerate.
• BCC has a high incidence rate among Caucasians aged 40 years and older.
• The epidermis is composed of stratified squamous epithelium and has five layers: stratum corneum, lucidum, granulosum, spinosum, and basale.
• The stratum lucidum is found only in thickened areas such as palms and soles and appears clear due to flattening of nuclei.
• The stratum corneum is the outermost layer of the skin and provides protection against water loss and microorganisms.
• Stratum corneum is made up of dead keratinocytes and provides protection against physical trauma and microorganisms.
• Basal cell carcinoma presents as a pearly papule that does not heal but grows slowly over time.
•  White spaces called vacuoles surround keratinocytes’ nuclear structures
•  Vacuoles of melanocytes surround their cytoplasm
•  The reticular dermis contains dense irregular connective tissue (primarily collagen) and is important for strength and to prevent the skin from tearing off
• Merocrine sweat glands produce watery sweat that leaves the cell by exocytosis through simple coiled tubular glands.
• Apocrine sweat glands produce fatty sweat through sebaceous glands that are simple branched acinar in shape
• Holocrine glands discharge the product through cell apoptosis after it reaches maturity.
• stratum corneum may contain orthokeratin that has no nucleus under normal conditions or it can have parakeratin which has increased cell turnover due to trauma and constant inflammation so it retains its nucleus
• Corneum is not present in oral mucosa which instead has a lamina propria
• when the spinosum and granulosum combine they are called the malpighan layer
• Blisters in pemphigus vulgaris occur in response to our autoimmune system producing IgG antibodies that destroy desmosomes
•  Acantholysis is the thickening of the epithelium.
• Pemphigus is seen histologically above the basement membrane. 
• Bullous pemphigoid is characterized by BP180 and BP230 which are responsible for subepithelial separation
• Pemphigoid is seen histologically under the basement membrane. It rarely occurs in the mouth and is best diagnosed with biopsies
• Mucous membrane pemphigoid is when autoantibodies against basement membrane components which play a role in blister formation. It is more common in females than males (2:1) unlike bullous pemphigoid which has no gender predilection.
•  Mucous membrane pemphigoid is not common in skin and has an harder blood diagnosis than bullous. 
• in psoriasis, the blood vessels in the dermis cause neutrophils to increase and this causes keratinocytes to proliferate rapidly causing a thicc corneum and easily broken barrier due to a thin basal layer thinner
• Etiology of psoriasis includes stimulation by superantigens and genetic predisposition of PSOR1 locus map on chromosomes 6 and HLA-Cw6 associated with early onset
• Aupitz’s sign is due to scale picking that produces a pinpoint hemorrhage
• Histologically, psoriasis presents similar to geographic tongue but is not correlated with it. They both present with elongation of rete ridges, hyperkeratosis and inflammation of papillary dermis. Clinical presentations can look like lichen planus and discoid lupus