Dermatopathology: Blistering disorders Flashcards
IHC marker for keratinocytes
Cytokeratin
Cytokeratin is an IHC marker for this
Keratinocytes
2 IHC markers for melanocytes
S100, HMB45
2 IHC markers for Langerhans cells
S100, CD1a
IHC marker for nerves
S100
2 IHC markers for vessels
Actin-muscle, CD34-endothelium
Flat, non-elevated, circumscribed, <5mm
Macule
Flat, non-elevated, circumscribed, >5mm
Patch
What is the difference between a macule and a patch?
Both are flat, non-elevated, and circumscribed
Macule is <5mm
Patch is >5mm
Elevated lesion, <5mm
Papule
What is the size of a macule?
<5mm
What is the size of a patch?
> 5mm
Elevated lesion, >5mm
Nodule
What is the difference between a papule and nodule?
Both are elevated lesions
Papule is <5mm
Nodule is >5mm
Elevated, flat-topped lesion, usually >5mm
Plaque
Fluid-filled cavity, <5mm
Vesicle
Fluid-filled cavity, >5mm
Bulla
What is the difference between vesicle and bulla?
Both are blisters; fluid-filled cavity
Vesicle is <5mm
Bulla is >5mm
Purulent vesicle or bulla
Pustule
Dry, flaky area of impaired cornification on skin surface
Scale
Dried collection of blood, serum, or pus on skin surface
Crust
Thickening of skin with increased skin markings due to chronic rubbing/scratching
Lichenification
Thinned area of skin
Atrophy
Skin elevation caused by dermal edema
Often itchy, usually resolves quickly
Wheal
Separation of nail from nail bed
Onycholysis
Describes skin lesion that appears in lines of trauma (e.g. scratch lines)
Koebner phenomenon
Small distal dilated blood vessels that appear close to skin surface
Telangiectasia
A traumatic lesion causing epithelial disruption and bleeding (a deep scratch)
Excoriation
Increased thickness of stratum corneum
Hyperkeratosis
Hyperkeratosis is an increased thickness of this layer
Stratum corneum
Hyperkeratosis with retained keratinocyte nuclei
Parakeratosis
Hyperkeratosis with no retention of keratinocyte nuclei
Orthokeratosis
Hyperplasia of stratum granulosa
Prominent keratohyalin granules
Hypergranulosis
Increased thickness of epidermis
Acanthosis
Intercellular edema in epidermis
Desmosomes easily seen due to fluid between epithelial cells
(intercellular bridges often indicate squamous cell involvement)
Spongiosis
Loss of intercellular keratinocyte adhesion
Acantholysis
Formation of spaces between cells, usually seen in basal cell-basement membrane zone
Vacuolization
Vacuolization is usually seen in this zone of the skin
Basal cell-basement membrane zone
Abnormal (premature) individual cell keratinization
Dyskeratosis
Linear pattern of melanocytic proliferation at dermal-epidermal junction
Lentiginous
Lentiginous is a linear pattern of melanocytic proliferation at this
Dermal-epidermal junction
Lentiginous is a linear pattern of proliferation of these cells at dermal-epidermal junction
Melanocytes
Infiltration of epidermis by inflammatory cells
Exocytosis
Complete loss of epidermis and exposure of dermis/subcutis
Ulceration
Incomplete loss of epithelium
Erosion
What attach suprabasal keratinocytes to each other?
Desmosomes
Protein in desmosomes that is more superficial in the epidermis
Desmoglein 1
Protein in desmosomes that is found deeper in the epidermis
Desmoglein 3
Problem with this structure results in intraepidermal splits
Desmosomes
Structure that attaches basal keratinocytes to basement membrane
Hemidesmosomes
Problem with this structure results in subepidermal splits
Hemidesmosomes
Anchoring filaments that provide stability to the dermal-epidermal adhesion
Collagen VII
Blister filled with acute inflammation
Pustule
Describes blistering disorders due to loss of keratinocyte intercellular attachment
Pemphigus
Most common form of Pemphigus
Pemphigus Vulgaris
What age does Pemphigus Vulgaris present?
40-60 year old
Bullous disorder with this typical patient:
40-60 year old
Male = female
May be life threatening
Pemphigus Vulgaris
What causes Pemphigus Vulgaris?
IgG Autoantibodies against desmoglein 3
Pemphigus Vulgaris is caused by IgG autoantibodies against this
Desmoglein 3
What type of split is present in Pemphigus vulgaris?
Suprabasal
Condition characterized by row of “tombstones”
Pemphigus Vulgaris
(due to basal cells remaining attached)
Condition where IgG produces “fishnet” pattern in direct immunofluorescence
Pemphigus Vulgaris
Type of bullae in Pemphigus Vulgaris
Flaccid; easily ruptured; painful
Phenomenon where a blister expands when pressure is applied
Nikolsky sign
Nikolsky sign in Pemphigus Vulgaris
Positive
Common initial site of Pemphigus Vulgaris
Oral mucosa
Pemphigus Vulgaris affects these sites
Mucosal sites and skin
(oral mucosa, esophagus, skin - head, trunk)
Who is more likely to have Pemphigus Vulgaris, male or female?
Equal
Bullous disorder caused by IgG autoantibodies against desmoglein 3
Pemphigus Vulgaris
Type of Pemphigus that is an endemic in Brazil
Pemphigus Foliaceus
Pemphigus Foliaceus involves antibodies against this
Desmoglein 1
Type of split in Pemphigus Foliaceus
Subcorneal
Is there mucosal involvement in Pemphigus Foliaceus?
No
There is no desmoglein 1 in mucosa
Is there mucosal involvement in Pemphigus Vulgaris?
Yes
Oral mucosa is common initial site
Pemphigus disorder involving erosions rather than bullae
Pemphigus Foliaceus
What causes Pemphigus Foliaceus?
Antibodies against desmoglein 1
Bullous disorder caused by antibodies against desmoglein 1
Pemphigus Foliaceus
What causes Paraneoplastic Pemphigus?
IgG against pemphigus and pemphigoid antigens
Type of Pemphigus caused by IgG against pemphigus and pemphigoid antigens
Paraneoplastic Pemphigus
Bullous disorder with same appearance as Pemphigus Vulgaris, but may have band of lymphocytes in dermis
Paraneoplastic Pemphigus
Paraneoplastic Pemphigus is most common with this neoplasm
Lymphomas
Bullous disorder most common with lymphomas
Paraneoplastic Pemphigus
Paraneoplastic Pemphigus can have the same appearance as Pemphigus Vulgaris, but may have a band of these
Lymphocytes in the dermis
Blistering disease due to autoantibodies against BPA of hemidesmosomes
Bullous Pemphigus
What causes Bullous Pemphigus?
IgG autoantibodies against BPA (Bullous Pemphigus Antigen) of hemidesmosomes
Is acantholysis present in Bullous Pemphigus?
No
Is acantholysis present in Pemphigus Vulgaris?
Yes
The pathogenesis of Bullous Pemphigus involves IgG against BPA of this structure
Hemidesmosomes
Split in Bullous Pemphigus
Subepidermal
with eosinophils
Bullous Pemphigus involves a subepidermal split with these cells
Eosinophils
What shows on direct immunofluorescence in Bullous Pemphigus?
Complement
Linear IgG along dermal-epidermal junction (DEJ)
Linear IgG along dermal-epidermal junction is seen on DIF in this blistering disease
Bullous Pemphigus
Blistering disease associated with celiac disease
Dermatitis Herpetiformis
Dermatitis Herpetiformis is associated with this
Celiac disease
Age at presentation in Dermatitis Herpetiformis
Peak teens to 20s
Who is more likely to have Dermatitis Herpetiformis, male or female?
Males
(2:1 male to female ratio)
Dermatitis Herpetiformis is more common in this population
Scandinavian
Blistering disease more common in Scandinavian populations
Dermatitis Herpetiformis
Bullous disorder that is an endemic in Brazil
Pemphigus Foliaceus
When wheat is digested, this is produced that is deamidated, binds to transglutaminase, and becomes a neoantigen
Gliadin
Form of transglutaminase in the intestine
Tissue translutaminase (TTG, TG2)
Form of transglutaminase in the skin
Epidermal transglutaminase (eTG, TG3)
In Dermatitis Herpetiformis, anti-eTG IgA deposits here
Tips of dermal papilla
What causes Dermatitis Herpetiformis?
Anti-eTG IgA deposits at tips of dermal papilla
(complement is fixed, leading to patches of vesicles on erythematous base)
Split in Dermatitis Herpetiformis
Subepidermal at tips of dermal papilla
Split is filled with neutrophils (pustules)
What is seen on DIF in Dermatitis Herpetiformis?
Granular IgA at dermal papillary tips
Granular IgA at dermal papillary tips is seen on DIF in this bullous disorder
Dermatitis Herpetiformis
Blistering disorder involving a subepidermal split at tips of dermal papilla
Dermatitis Herpetiformis
Blistering disorder involving a subepidermal split filled with neutrophils (pustules)
Dermatitis Herpetiformis
Blistering disorder when clusters of vesicles/pustules are formed on an erythematous base
Very pruritic
Dermatitis Herpetiformis
Locations on the body where clusters of vesicles/pustules are found in Dermatitis Herpetiformis
elbows, knees, buttocks
What causes Epidermolysis Bullosa?
Defective proteins at dermis-epidermal junction results in mechanical fragility
Bullous disorder caused by defective proteins at DEJ, resulting in mechanical fragility
Epidermolysis Bullosa
Bullous disorder where friction blisters form easily
Epidermolysis Bullosa
Form of Epidermolysis Bullosa that is mild with no scarring
EB simplex
2 gene mutations in EB simplex
Keratin 14 and 5
Most severe form of Epidermolysis Bullosa, forms scars
Dystrophic EB
Dystrophic EB is due to defective this
Anchoring filaments (type VII collagen)
Split in Epidermolysis Bullosa
Most forms have subepidermal split
Bullous disorder characterized by friction blisters
Epidermolysis Bullosa
Autoimmune form of Epidermolysis Bullosa
Epidermolysis bullosa acquisita
Onset of Epidermolysis bullosa acquisita
Adult onset
Bullous disorder where friction blisters are produced at sites of trauma (fingers, feet, oral)
Epidermolysis bullosa acquisita
What causes Epidermolysis bullosa acquisita?
IgG autoantibodies against type VII collagen
Bullous disorder caused by IgG autoantigens against type VII collagen
Epidermolysis bullosa acquisita
Split in Epidermolysis bullosa acquisita
Subepidermal
DIF appearance of Epidermolysis bullosa acquisita
Linear IgG along basement membrane
Linear IgG along basement membrane is seen on DIF in this bullous disorder
Epidermolysis bullosa acquisita
In Dermatitis herpetiformis, the subepidermal split at the tips of dermal papilla are filled with these cells
Neutrophils
Bullous disorder with a subepidermal split filled with neutrophils, forming pustules
Dermatitis herpetiformis
Bullous disorder with a subepidermal blister with eosinophils
Bullous pemphigus
Bullous pemphigus involves a subepidermal blister with these
Eosinophils