Dermatopathology Flashcards
What stains can be used to differentiate Paget’s disease from Bowen’s disease?
Pagets: CAM5.2+, CK903- Bowens: CAM5.2-, CK903+
What is the salivary gland-skin adnexal tumor syndrome called and what tumors do they get?
Brooke-Spiegler syndrome rare familial autosomal dominant condition of multiple cylindromas, trichoepitheliomas and eccrine spiradenomas
What mutation is seen in pilomatrixoma and pilomatrix carcinoma?
activating mutations of CTNNB1 gene encoding beta-catenin
beta catenin staining: NUCLEAR in basaloid cells, cytoplasmic and membranous in intermediate basaloid cells, and NO staining in ghost cells
What are the two most common tumors to arise in nevus sebaceous?
- Trichoblastoma (looks just like pilomatrixoma except no ghost cells and usually occurs on scalp, characteristically contains fibromyxoid stroma as an intergral part of tumor, stroma exhibits areas of condensation indenting the adjacent basaloid epithelium resembling primitive hair papillae and are referred to as papillary-mesenchymal bodies which are characteristic for this lesion)
- Syringocystadenoma papilliferum
Board Q from Osler lecture!
1) What are the contents of a spongiotic microvesicles?
2) What are the contents of Pautrier microabscesses?
3) What are the contents of microabscesses of Munro?
1) Normal lymphocytes and Langerhan cells
2) Atypical/neoplastic lymphocytes and Langerhans cells
3) Neutrophils and Langerhans cells
What is the prototypic lesion associated with superficial perivascular and interstitial pattern of dermatitis?
Urticaria
What is the prototypic lesion associated with superficial and deep perivascular pattern of dermatitis?
Superficial and deep perivascualr with mixed inflammation and eosinophils is due to bug, drug or other allergen exposure
What is the prototypic lesion associated with spongiotic dermatitis?
Pityriasis rosea
However, spongiotic derm is split into two categories both of which overlap with tinea:
1) with eos–drug, allergic contact, bug (arthropod and
insect) , partially treated psoriasis
2) no eos–Contact irritant dermatitis which includes seborrhoic derm, Id reaction, nummular dermatitis (aka
discoid eczema)
What is the differential when you see psoriasiform dermatitis?
- Clear cell acanthoma
- Chronic spongiotic dermatitis
- Pityriasis rosea (less likely)
- Lichen simplex chronicus
- Mycosis Fungoides
- FUNGAL DISEASE(s) – TINEA!!
What is prototypic lesion associated with interface dermatitis?
Erythema multiforme (remember, this is an acute reaction but has all lymphs which is important because skin doesn’t stick to the acute/chronic rules of inflammation)
*just the interface part is EM minor but full thickness epidermal necrosis is EM major and equals Stevens Johnson or TEN clinically
If you are shown this pattern of a lichenoid infiltrate WITH psoriasiform hyperplasia, what ONE entity should you think about?
SYPHILLIS
What are the three main entities you should think of it you see a palisading granulomatous skin lesion and how do you tell them apart?
Granuloma annulare: may be mucin in center (glycosaminoglycans) – colloidal iron or alcian
blue stains
- *Rheumatoid nodule**: Fibrin – fibrinogen or Fraser or PTAH or Lendrum stain
- *Necrobiosis Lipoidica (diabeticorum)**: Central areas of collagen degeneration but can have mucin too – trichrome stain or collagen stain
Infectious etiologies are in the differential!
If you see SUBCORNEAL bullous/vesicular lesion, what 2 things should you think of?
Sneddon Wilkinson aka Subcorneal pustular dermatosis
and Staph scalded skin syndrome
What is the main differential with pemphigus vulgaris and how do you tell them apart?
Hailey-Hailey Disease (benign familial pemphigus)
This will usually only be on flexor surfaces, not all over like PV.
Autosomal dominant defect in Ca pump gene (ATP2C1) on 3q21-q24
Buzz word for Hailey-Hailey is typically, “dilapidated
brick wall” appearance with full-thickness and
suprabasilar acantholysis
What is the main differential for subepidermal bullae?
Bullous pemphigoid vs Epidermolysis bullosa
acquisita
*Careful here–they can show you bulla what doesn’t quite look like BP because there is re-epithelization!
On IF, you get linear deposits of C3 and IgG but C3 is the important one here!
If you have linear deposition on the ROOF of bulla or both roof and bottom=BP
If you have linear deposits only on the BOTTOM, it is EBA
What entity shows the IF pattern shown?
Porphyria cutanea tarda
Acral site, cell-poor blister shows “festooning” (dermal
papillae preserved), caterpillar bodies adherent to epidermis
INFLAMMATION IS ABSENT OR NEARLY
ABSENT
What entity is characterized by neutrophils +/- eosinophils in the DERMAL PAPILLAE and you can see a subepidermal split later in the course? It will shows papillary dermal deposition of IgA
Dermatitis herpetiformis (aka Duhring’s disease)
The only way to tell apart from linear IgA disease is IF (and this will happen in older people instead of younger Celiac patients)
If you see a lichenoid AND acantholytic pattern, what disease should you think of?
Paraneoplastic pemphigus
IF will show intracellular IgG with linear C3 deposition
Think of it as an overlap between pemphigus vulgaris and bullous pemphigoid
What disease is characterized by autosomal dominant
disease, greasy papules on head and neck, acanthosis, suprabasal acantholytic dyskeratosis with “corps ronds”
(dyskeratotic cells) and grains (parakeratotic cells)?
Darier’s Disease
Autosomal dominant defect in Ca2+ATPase gene (ATP2A2) 12q23-q24.1
IF is negative
In the skin, how do you tell the difference between herpes and varciella infection based on histology?
Herpes will be superficial
If you see “herpes inclusions” that only involve the hair follicle, it is more likely to be varicella
What is the adnexal tumor that will at low power look like a basal cell on bottom and a verruca on top?
Tricholemmoma
What structures help distinguish BCC from trichoepithelioma?
Mesenchymal-papillary body (so-called “ball and
claw”)
Desmoplastic trichoeps will have these too
These are fibroblastic bulbar differentiation resulting abortive hair papillae and it has the so-called “ball and claw” look
Name this specialized type of BCC found in groin, breast and ears.
Fibroepithelioma of pinkus
It is a eccrine duct BCC
What are Max Joseph spaces?
They represent focal subepidermal clefts formed by confluent vacuoles, typically encountered in the setting of lichen planus.
Erythema induratum represents a form of lobular panniculitis that is associated with what?
Tuberculosis
Classically affects lower legs and tends to show symmetric involvement. Granulomatous inflammation is a prominent feature of this disorder.
What two clinical findings can be seen in patients with angiomatoid fibrous histiocytoma?
Polyclonal gammopathy and anemia
These usually arise on the extremities in young patients and frequently accompanied by systemic symptoms like fever and weight loss. They are positive for EMA, desmin and CD68
What syndrome has multiple of these skin tumors?
Birt-Hogg-Dube
(fibrofolliculoma)
Name this lesion.
Cellular Blue Nevus
Here is a regular blue nevus
Name this lesion.
Proliferating trichilemmal cyst
What lesion is this which can mimics the necrobiotic granulomatous diseases?
Epithelioid sarcoma
KERATIN +, VIMENTIN +, EMA +, CD34 + (50%)
NODULES +/- ULCERATION-DISTAL EXTREMITIES OF YOUNG ADULT MEN
What is this lesion?
If a patient has multiple of these, what syndrome should be on the differential?
Sebaceous adenoma
Muir-Torre syndrome
