Download Skin Block

Skin Block
• Introduction To Diseases Of The Skin
• Acneiform, Alopecias, and Pigmentary
Disorders
• Eczemas, Papulosquamous, and Vesiculobullous Skin Disease
• Skin Neoplasms
• Drug Eruptions
• Skin Signs of Systemic Disease
Learning Objectives
At the end of the session the students will be able to:
• Describe the layers of the skin, including the layers of the epidermis
• Utilize the dermatology vernacular to allow the appropriate description of lesions
• Model a comprehensive dermatologic exam, including lesion description and distribution
Introduction to Skin
Kerri E. Rieger, MD, PhD
Stanford Dermatology and Pathology
Why study the skin… Clinical Definitions in Dermatology:
Morphology
MACULE
‐ small, flat, non‐palpable lesion ‐ <10 mm in diameter
PATCH
‐ small, flat, non‐palpable
lesion ‐ <10 mm in diameter
PAPULE
‐ small, superficial, circumscribed, palpable lesion elevated above the skin surface
‐ <10 mm in diameter
PLAQUE
‐ palpable lesion, elevated above the skin surface
‐ >10 mm
NODULE
‐ firm (indurated) lesion that is thicker or deeper than the average papule or plaque (a nodule that is subcutaneous might not elevate the skin surface)
VESICLE
‐ elevated lesion that contains clear fluid
‐ a small blister
‐ < 10 mm in diameter BULLAE
‐ elevated lesion that contains clear fluid
‐ >10 mm in diameter
PUSTULE
• superficial elevated lesion that contains yellow fluid (pus)
Macule
flat lesion <1cm
Papule
elevated lesion <1cm
Nodule
palpable lesion, usually >1cm and deeper in the dermis or subcutis
Patch
Flat lesion >1cm
Plaque
elevated lesion >1cm
Vesicle
fluid filled lesion <1cm
Pustule
purulent exudate filled lesion
Bulla
fluid filled lesion >1cm
Macule
flat lesion <1cm
Papule
elevated lesion <1cm
Nodule
palpable lesion, usually >1cm and deeper in the dermis or subcutis
Patch
Flat lesion >1cm
Plaque
elevated lesion >1cm
Vesicle
fluid filled lesion <1cm
Pustule
purulent exudate filled lesion
Bulla
fluid filled lesion >1cm
Approach to morphological description
Size
Measure in cm
Color Black, white, blue, purple, brown, tan, red, pink, yellow, .. violaceous, erythematous, hypopigmented, hyperpigmented, dusky
Basic/primary morphology
Macule, patch, papule, plaque, nodule, tumor, vesicle, bullae, pustule
Secondary morphology
Scale, crust, erosion, ulceration, excoriation, eschar, lichenification, atrophy Demarcation
Well‐demarcated, poorly‐demarcated
Arrangement/conf Linear, grouped, scattered, reticular, arcuate, iguration
annular Distribution
Generalized, unilateral, bilateral, chest, back, face, upper or extremities, sun‐exposed Approach to morphological description
Size
Measure in cm
Color Black, white, blue, purple, brown, tan, red, pink, yellow, .. violaceous, erythematous, hypopigmented, hyperpigmented, dusky
Basic/primary morphology
Macule, patch, papule, plaque, nodule, tumor, vesicle, bullae, pustule
Secondary morphology
Scale, crust, erosion, ulceration, excoriation, eschar, lichenification, atrophy Demarcation
Well‐demarcated, poorly‐demarcated
Arrangement/conf Linear, grouped, scattered, reticular, arcuate, iguration
annular Distribution
Generalized, unilateral, bilateral, chest, back, face, upper or extremities, sun‐exposed “The skin examination is notable for (____)cm (_________) , (____________)
size
color
primary lesion
with (________) in a (__________) configuration, located over the (__________).”
secondary changes
configuration
distribution
“The skin examination is notable for (____)cm (_________) , (____________)
size
color
primary lesion
with (________) in a (__________) configuration, located over the (__________).”
secondary changes
configuration
distribution
“The skin examination is notable for (____)cm (_________) , (____________)
size
color
primary lesion
with (________) in a (__________) configuration, located over the (__________).”
secondary changes
configuration
distribution
“The skin examination is notable for (____)cm (_________) , (____________)
size
color
primary lesion
with (________) in a (__________) configuration, located over the (__________).”
secondary changes
configuration
distribution
“The skin examination is notable for (____)cm (_________) , (____________)
size
color
primary lesion
with (________) in a (__________) configuration, located over the (__________).”
secondary changes
configuration
distribution
ABCDEs
Approach to full body skin examination
• Have an adequately lit room • Have the patient fully gowned will improve your exam
• Have a systematic order that you follow consistently, so that you don’t forget to check easy‐to‐miss locations (e.g. the conchal bowl, in the mouth, alar creases, interdigital spaces, intergluteal cleft, soles, etc)
• Consider an integrated skin examination (internist can perform full skin check on chest/back while listening to heart/lungs; face while feeling for lymphadenopathy; legs while checking reflexes and edema
Skin structure and function
Histology of Skin
Histology of Skin
e = epidermis
d = dermis
h = hair follicle
g = eccrine sweat gland
s = sebaceous gland
lc = Langerhans cell
m = Merkel cell
b = basal cell
f = fibroblast
mc = mast cell
dc = dendritic cell
v = blood vessel
sc = stratum corneum
Normal Epidermal Histology
Stratum Corneum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
Dermis
Components of the Epidermis
• Epidermis
– Keratinocytes
– Melanocytes
– Langerhans Cells
– Merkel Cells
Keratinocyte
• Form functional barrier against environment
• Contain keratins (intermediate filaments)
Hemiesmosomes
Desmosomes
Melanocyte
• Melanin producing cells found in skin, inner ear, choroid and iris of the eye
• Ratio of melanocytes to basal cells = 1:4‐
1:10
• Form melanosomes
(distinct organelle) and transfer to keratinocytes
Melanosome on EM
Langerhans Cells
• Distinct population of antigen presenting cells; function as intra‐epidermal macrophages
• Will migrate to regional lymph nodes when stimulated
Birbeck Granules
Merkel Cells
• Located in basal layer
• Found mainly on tactile areas of hair‐bearing skin, taste buds, anal canal, labial epithelium, and around eccrine glands
• Involved in touch sensation
– one free nerve ending from dermis touches up to 50 Merkel cells to form a “Merkel cell‐neurite” complex CK20
DEFINITIONS IN DERMATOPATHOLOGY
Hyperplasia
Increase in the number of cells of the epidermis
Hyperkeratosis
Thickening of the stratum corneum
Parakeratosis
Flattened and retained keratinocyte nuclei within the stratum corneum
Follicular plugging Hyperkeratosis within hair follicle Hyper/Hypogranulosis
Increased/decreased thickness in the granular layer
Acanthosis
Thickened squamous/spinous cell layer Papillomatosis
Elevation of adjacent dermal papillae above the surrounding epidermal surface Spongiosis
Intercellular edema
Exocytosis Inflammatory cells within epidermis, usually with spongiosis (usually refers to lymphocytes, and implies a benign process) Epidermotropism
Abnormal cells within the epidermis without significant spongiosis (seen in Mycosis Fungoides, Melanoma mets)
Acantholysis
Separation & rounding up of keratinocytes because of loss of intercellular adhesions Dyskeratosis
Abnormally or prematurely keratinised eosinophilic keratinocytes, identified by prominent eosinophilic (red‐staining) cytoplasm Vacuolar degeneration Damage to the basal layer, with intracellular oedema and vacuoles. May be associated with colloid body formation and clear spaces at the dermal‐
epidermal junction, sometimes resulting in a subepidermal blister. Basket Weave Orthokeratosis
Compact Orthokeratosis
Hyperkeratosis
Parakeratosis
Acanthosis
Papillomatosis
Hyper‐ and Hypogranulosis
Necrotic Keratinocytes = Civatte Bodies
(or Colloid Bodies in the dermis)
Acantholysis
Tissue Reaction Patterns in Dermpath
The Spongiotic Reaction Pattern
•
•
•
•
Widening of intercellular spaces
Elongation of intercellular bridges (desmosomes)
Inflammatory cells in the epidermis: lymphs, eos, neuts
Seen commonly in “eczema”
Wide Intercellular Spaces/Eosinophils
Lymphocyte Collections in Epidermis
Neutrophils Within the Spongiosis
Intense Spongiosis with Vesiculation
NOTE: Smooth Borders
Subacute Spongiotic Dermatitis
Chronic Spongiotic Dermatitis
Irregular Length of Rete Ridges, Jagged Edges
The Psoriasiform Reaction Pattern
Regular Elongation of Rete Ridges
The Lichenoid Reaction Pattern
Band‐like infiltrate that hugs the dermoepidermal junction
The Vesiculobullous Reaction Pattern
Biopsy techniques
Thank you!