Dermatopathology (Part 4 of 4) Flashcards
What is mycosis fungoides?
a cutaneous T-cell lymphoma of CD4 T helper cells in the skin
how does mycosis fungoides present? (age, where, what do they look like)
usually >40 yo with truncal lesions; scaly red-brown patches; raised scaling plaques (can be confused with psoriasis); fungating nodules
eczema like lesions in patients with mycosis fungoides usually means what?
it is in the early stages
multiple tumor nodules in patients with mycosis fungoides usually means what?
systemic spread
what is sezary syndrome?
seen in some cases of mycosis fungoides; erythroderma, diffuse erythema and scaling of entire body surface
what is the morphology of sezary cells?
markedly folded nuclear membrane CEREBRIFORM contour
what is the histological hallmark of cutaneous t cell lymphoma?
the presence of atypical cells that characteristically form band-like aggregates within the superficial dermis and invade the epidermis as single cells and small clusters known as Pautrier microabscesses
what is urticaria pigmentosa?
a cutaneous form of mastocytosis that primarily affects children
how does urticaria pigmentosa present?
multiple, widely distributed lesions, round-oval, red-brown, nonscaling papule and small plaques; around 10% of cases have systemic disease with mast cells infiltrating organs (mostly seen in adults)
what is solitary mastocytoma?
usually seen in young kids; pink-tan-brown nodule with possible blister formation
many of the signs and symptoms of mastocytosis occurs when mast cells degranulate- what happens when mast cells degranulate?
histamine and heparin are released
what are two signs that can be seen with mastocytosis?
darier sign and dermatographism
what is darier sign?
localized area of dermal edema and erythema (wheal) when skin is rubbed
what is dermatographism?
area of dermal edema resembling a hive, result of local stroking skin with pointed instrument
what are the systemic symptoms associated with mastocytosis?
pruritus and flushing or bone pain
why is there bone pain seen in mastocytosis?
mast cell infiltration causes it
what could be a clue that a patient has mastocytosis?
if they are presenting with osteoporosis in premenopausal women or in men –> due to excessive histamine release in the bone marrow
what causes mastocytosis?
a point mutation in KIT receptor tyrosine kinase–> leads to mast cell growth and survival
what is the histological appearance of mastocytosis?
spindle shaped and stellate mast cells, fibrosis, edema, and few eosinophils
what stain can you use to diagnose mastocytosis?
giemsa (shows metachromatic granules)
what is ichthyosis?
impaired epidermal maturation, hyperkeratosis that results in a clinically fish-like scale appearance
what are three examples of acute inflammatory dermatoses?
urticaria, acute eczematous dermatitis, erythema multiforme
generally speaking, what are acute inflammatory dermatoses?
acute lesions that last from days to weeks that are characterized by inflammatory infiltrates (usually lymphocytes and macrophages) NOT NEUTROPHILS
generally speaking, what are chronic inflammatory dermatoses?
chronic lesions persist for months to years and are often associated with changes in epidermal growth or dermal fibrosis
what causes urticaria?
localized mast cell degranulation; it is an antigen induced release of vasoactive mediators from mast cells
what can urticaria cause?
wheals or angioedema
what is the common presentation of urticaria?
20-40 yo, less than 24 hours, sites exposed to pressure
how does urticaria look on a macro level?
small, pruritic papules to large edematous plaques; individual lesions may coalesce to form annular, linear, or arciform configurations
how does urticaria look on a micro level?
sparse superficial perivenular infiltrate of mononuclear cells (so around the veins)
which antibody is associated with urticaria?
IgE
what is one of the most common skin disorders?
acute eczematous dermatitis
what causes acute eczematous dermatitis?
external application of Ag or ingested food or drug
what are the 5 main causes of acute eczematous dermatitis?
allergic contact, atopic dermatitis, drug-related, photoeczematous dermatitis, primary irritant dermatitis
what is the official name of poison ivy/oak and what in it causes acute eczematous dermatitis?
Rhus toxicodendron- Urushiol
what is treatment of acute eczematous dermatitis?
it is palliative, no cure- just treat symptoms
what type of reaction is acute eczematous dermatitis?
T-cell mediated inflammatory reaction (type IV hypersensitivity)
how does acute eczematous dermatitis look on a macro level?
red, papulovesicular, oozing, and crusted (impetiginization) lesions
what do you get if acute eczematous dermatitis persists? (2 things leading to something)
you develop acanthosis and hyperkeratosis–> raised scaling plaques
what is spongiosis?
acute eczematous dermatitis, edema in the intracellular spaces, splaying them apart, particularly in the stratum spinosum
if eczematous dermatitis was set off by drugs, how might you tell?
there might be a lot more eosinophils present
what is erythema multiforme?
it is uncommon, self-limited hypersensitivity reaction to certain infections and drugs
How is erythema multiform characterized?
by keratinocyte injury mediated by CD8+ T lymphocytes
what is located in the center of the erythema multiform lesions? and the periphery?
CD8 cytotoxic T cells are in the center; CD4 T cells and Langerhans cells are in the periphery
what is the classic morphology of erythema multiforme?
targetoid lesions
what is interface dermatitis seen in erythema multiforme?
dermal edema, lymphocyte infiltration along the dermoepidermal junction, associated with dermal edema and degenerating keratinocytes
what are two important variants of erythema multiform to know about?
stevens-johnson and toxic epidermal necrolysis
what is stevens-johnson?
seen in children; extensive skin involvement plus oral mucosa, conjunctiva, urethra, genital, and perianal areas; secondary infections can lead to life-threatening sepsis
what is toxic epidermal necrolysis?
diffuse necrosis and sloughing of cutaneous and mucosal epithelia; resembles extensive burns- also life threatening
what are three examples of chronic inflammatory dermatoses?
psoriasis, seborrheic dermatitis, and lichen planus
what is psoriasis?
a chronic inflammatory dermatosis with an autoimmune basis; may also be asosciated with myopathy, and AIDS
what is the morphology of psoriasis?
pink to salmon colored plaque covered by loosely adherent silver scale
what is the Koebner phenomenon?
induce psoriatic lesions in susceptible patients by trauma, starts a self-perpetuating local inflammatory response
besides the skin what else can psoriasis affect and how?
the nails: pitting, dimpling, yellow-brown discoloration (oil slick); oncolysis (separation of the nail plate from the underlying bed)
what are the histological features of psoriasis?
marked acanthosis, regular downward elongation of rete ridges “test tubes in a rack”
what is munro microabscesses?
seen in psoriasis; when small PMN aggregates in parakeratotis stratum corneum
what is the Auspitz sign?
multiple, minute, bleeding points when the silver scale is lifted from the plaque
there have been excellent clinical responses observed in patients with psoriasis when treated with what?
TNF and IL-17 inhibitors
what is seborrheic dermatitis?
affects 5% of the population- more common than psoriasis; regions with increased sebaceous glans: scalp, forehead, external auditory canal; inflammation of epidermis; NOT A DISEASE OF SEBACEOUS GLAND
what is seborrheic dermatitis associated with?
Parkinson’s disease; increased sebum production secondary to dopamine deficiency leads to increased seborrheic dermatitis; when you treat with levodopa–> there is a decrease in oil and improved seborrhea
a severe form of seborrhic dermatitis that is difficult to treat was once common in what population of people?
HIV individuals with low CD4 counts; but incidence has fallen with the advent of effective antivrial therapy
what is follicular lipping?
seen in cases of seborrheic dermatitis; mounds of parakeratosis containing neutrophils and serum are present at the ostia of hair follicles
how can lichen planus be described?
pruritic, purple, polygonal, planar, papules, and plaques
how do you treat lichen planus?
you don’t have to- it is self limited- resolves in 1-2 years; there is a post inflammatory hyperpigmentation left after resolution
people with lichen planus are at increased risk of what?
squamous cell carcinoma
koebner phenomenon is seen in what two disorders?
psoriasis and lichen planus
what is wickham striae?
seen in lichen planus; papules highlighted with white dots, created by areas of hypergranulosis
what is lichen planus/ how does it present? (not the 6 P’s, but what do the lesions look like and where?) 5 places
multiple symmetrical lesions especially on the extremities, wrists, elbows, and glans penis; 70% of cases have oral mucosal lesions
what does lichen planus look like histologically?
dense cutaneous infiltrate of lymphs along the dermoepidermal junction (interface dermatitis); sawtoothing and CIVATTE bodies
what are civatte bodies?
seen in lichen planus; they are anucleated necrotic basal cells incorporated into the inflamed papillary dermis
what is the buzzword for lichen planus?
civatte bodies
How can blistering (bullous) diseases be divided?
into inflammatory blistering disorders and noninflammatory blistering disorders
what are the inflammatory blistering disorders?
pemphigus, bullous pemphigoid, and dermatitis herpetiformis
what are the noninflammatory blistering disorders?
epidermolysis bullosa and prophyria
bullous diseases produce dramatic lesions which can be fatal if untreated; what else is important to remember about diagnosing bullous diseases?
blisters occur at different levels of the skin; histologic assessment is essential for accurate diagnosis
what is pemphigus?
when IgG autoantibodies disrupt intracellular lesions leading to blisters; there is a net-like pattern of intracellular IgG deposits
what is the treatment for pemphigus?
immunosuppressives
what is acantholysis?
seen in pemphigus; it is the dissolution of intercellular bridges connecting squamous epithelial cells
what are the 5 different types of pemphigus?
vulgaris, vegetans, foliaceus, erythromatosus, and paraneoplastic pemphigus
what is pemphigus vulgaris?
the most common form of pemphigus, it affects the mucosa and skin of the scalp, face, axilla, groin, trunk, and points of pressure ; the superficial vesicles rupture easily
what is pemphigus vegetans? (where do you see it)
rare; large and wart like plaques studded with pustules; seen in the groin, axilla, and flexural surfaces
what is pemphigus foliaceus?
benign, seen in people from brazil; seen on the scalp, face, chest, and back; erythema and crusting
what is pemphigus erythromatosus?
localized less severe form of foliaceous; affects the malar area of the face (just like lupus)
what is paraneoplastic pemphigus?
associated with malignancies such as NHL and lymphoid neoplasms
what level does pemphigus foliaceus affect?
the stratum granulosum level- it is subcorneal- so it is right under the keratin at the top of your epidermis
what level does pemphigus vulgaris affect?
above the basal layer- suprabasal- so it is above the basal layer- you’re going to retain those basal layer cells of the epidermis, and the rest of it is going to come off; if you have that much on top of it, it is going to be harder to rupture compared to the one that is subcorneal
what layer does bullous pemphigoid affect?
subepidermal layer- the whole epidermis comes off
what is the buzzword for the histology of pemphigus vulgaris?
tombstone appearance
what is bullous pemphigoid?
seen in the elderly, typically on the inner aspects of thighs; flexor surfaces of forearms, axilla, groin, and lower abdomen; there are antibody deposits at the dermoepidermal junction
what is dermatitis herpetiformis?
urticarial and grouped vesicles; bilateral and symmetrical grouped lesions on extensor surfaces of elbows, knees, upper back, and buttocks
what is dermatitis herpetiformis associated with?
celiac disease (these people develop IgA antibodies against gluten) these antibodies cross react with reticulin to form a subepidermal blister
how can you treat dermatitis herpetiformis?
remove gluten from the diet
where is the blister for dermatitis herpetiformis?
subepidermal blister
what antibody is associated with bullous pemphigoid?
IgG
what antibody is associated with dermatitis herpetiformis?
IgA
what is epidermolysis bullosa?
a noninflammatory blistering disorder; inherited defects in structural proteins; blisters at sites of pressure, rubbing, or trauma at or soon after birth
what is porphyria?
a noninflammatory blistering disorder; a group of inborn or acquired disturbances in porphyrin metabolism
what are porphyrins?
pigments normally present in Hgb, myoglobin, and cytochromes
how does porphyria typically present?
urticaria and vesicles associated with scarring and exacerbated by sunlight
where is the blister with epidermolysis bullosa?
subepidermal blister but NO INFLAMMATION
what is rhinophyma and what is it associated with?
it is a permanent thickening of the nasal skin; associated with the 4th stage of rosacea
what is rosacea associated with?
high cutaneous levels of antimicrobial peptide cathelicidin
how do open comedones in acne vulgaris appear?
central black keratin plug
how do closed comedones in acne vulgaris appear?
keratin plug trapped beneath the epidermal surface, potential for follicular rupture and inflammation
what is the bacteria that causes acne?
propionibacterium acnes
what is acne conglobate?
a severe variant of acne vulgaris, there is sinus tract formation and dermal scarring
what is the treatment for P. acnes?
antibiotic for P. acnes; but also maybe isotretinoin (it has antisebaceous action)
what is panniculitis?
inflammatory reaction in the subQ adipose tissue
what are two forms of panniculitis?
erythema nodosum and erythema induratum
what is erythema nodosum?
the most common form of panniculitis; it is poorly definied but exquisitely tender erythematous plaques and nodules
what can be said about diagnosing erythema nodosum?
it can always be seen- you should palpate for it–> it feels ropy
what type of reaction is erythema nodosum considered to be?
a delayed hypersensitivity reaction to microbial or drug related antigens
what bacteria could cause erythema nodosum?
beta-hemolytic streptococcal infection
what drugs could cause erythema nodosum
sulfonamides or oral contraceptives
What is the uncommon type of panniculitis?
erythema induratum
who does erythema induratum seem to affect primarily?
adolescents and menopausal females
what exactly is erythema induratum?
primary vasculitis of deep vessels supplying fat lobules of the subQ–> leads to fat necrosis and inflammation
how does erythema induratum present?
erythematous slightly tender nodule that usually ulcerates; early lesion: necrotizing vasculitis of small-medium arteries and veins in deep dermis and subQ
how can erythema induratum be described? (what type of inflammation and what zones)
granulomatous inflammation and zones of caseous necrosis involving fat lobule
What is verrucae?
warts; squamoproliferative disorders caused by HPV
anogenital warts are caused by what strain(s) of HPV?
types 6 and 11
what can HPV type 16 be associated with?
in situ SCC of the genitalia and with bowenoid papulosis
what is bowenoid papulosis?
genital lesions of young adults with the histiologic appearance of carcinoma in situ, but which usually regress spontaneously
what are HPV subtypes 5 and 8 associated with?
SCC, especially in individuals with epidermodysplasia verruciformis
what is pathoneumonic for HPV? (on a micro level)
the Koilocytosis, which is just cytoplasmic vacuolization
what can be seen insides warts?
keratohyaline granules
what is molluscum contagiosum?
a common, self-limited poxvirus infection
how does molluscum contagiosum look?
brick shaped, dumbbell shaped DNA core
how does molluscum contagiosum present? (when, who, where, how do they feel, and how do they look)
usually after direct contact, children and young adults, trunk and anogenital regions; firm often pruritic, pink-skin colored umbilicated papules
what is the buzz word for molluscum contagiosum?
the papules are UMBILICATED
what does the histology of molluscum contagiosum show?
molluscum bodies: which is just the virus
what is impetigo?
a common superficial bacterial infection of the skin; highly contagious; usually seen in otherwise healthy kids
what causes impetigo?
staphylococcus aureus–> it has a toxin that causes epidermal injury (the toxin cleaves desmoglein 1)
how does impetigo present?
as an erythematous macule initially, then multiple small pustules which break leaving shallow erosions; also a honey colored crust
what happens if the honey colored crust is not fully removed from patients with impetigo?
new lesions form around the periphery and extensive epidermal damage may occur
superficial fungal infections are confined to what skin layer?
stratum corneum
tinea versicolor is a superficial fungal infection of what?
the upper trunk
what causes tinea versicolor?
malassezia furfur- A YEAST
how can you stain for tinea corpis and other superficial fungal infections?
using the PAS stain–> hyphae stains bright like magenta
