Dermatopathology Flashcards

Question

Leser–Trélat Sign

Answer 1

* Abrupt ↑ in size or number of seborrheic keratoses * Paraneoplastic cutaneous marker associated w/ an internal malignancy

Answer 2

* **Epidermal proliferation** * Variable combinations of **hyperkeratosis, papillomatosis, acanthosis** * Keratinocytes often appear **basaloid** * **Often have pseudo-horncysts** * “Pseudo” b/c they connect to surface and represent papillomatosis * Often abundant melanin in basal layer or throughout epidermis

Answer 3

* **Skin-colored to brown papules of eyelids, neck, axilla or groin** * Often **pedunculated** * Very common * ↑ incidence w/ aging and obesity

Answer 4

* **Pedunculated papule** * Epidermis often extends almost completely around specimen when sectioned * **Papillomatosis** and **acanthosis** common * **± Epidermal atrophy** * Dermis consists of loose CT that is often pale * Dilated blood vessels common

Answer 5

* **Walled-off cavity filled w/ keratin, mucin or fluid** * Classified based on location, contents, type of epithelial lining, and adnexa presence * Clinical manifestation: * Firm, well-circumscribed, dermal or subcutaneous nodules * Often moveable

Answer 6

* Contains lamellated keratin * Lined by squamous epithelium * Sometimes flattened w/ a granular layer

Answer 7

* Contains amorphous, dense and compact, homogenized keratin * Lined by squamous epithelium * Keratinocytes are often pale * There is no granular layer * Calcification common w/in cyst

Answer 8

* Wall commonly resembles epidermoid cyst * Lined by squamous epithelium * Contains multiple appendages budding outward from its wall * Small hair follicles * Sebaceous glands * Eccrine glands * Apocrine glands

Answer 9

* Cyst wall consists of rugated squamous epithelium * Wrinkled eosinophilic refractile cuticle of keratin instead of a granular layer * Sebaceous glands w/in or adjacent to cyst wall, opening into cyst * Only “true” sebaceous cyst

Answer 10

* Common, precancerous ill-defined white-red papule * Found in sun-damaged areas * low-grade atypia of epithelium vs precursor lesion to early low-grade carcinoma in situ * analogous lower grade lesion of intraepithelial neoplasia seen in cervix or vulva

Answer 11

* Often hyperkeratosis * Sometimes ulceration * Parakeratosis especially overlying atypical keratinocytes * Partial-thickness atypical keratinocytes * Nuclear pleomorphism * Atypical mitosis * Disordered maturation * Often spares epidermis above adnexa * Solar elastosis in dermis

Answer 12

“Bowen’s disease” * Common hyperkeratotic erythematous plaque * Often crusted on sun-exposed or covered skin * Full-thickness atypia of epidermal keratinocytes over a broad zone

Answer 13

* Parakeratosis, hyperkeratosis, acanthosis * Atypical keratinocytes with * Nuclear pleomorphism * Atypical mitosis * Disordered maturation throughout epidermis (all layers) * Atypical keratinocytes have not invaded through BM of dermal-epidermal junction

Answer 14

* **Second most common type of skin cancer** * Red papule, nodule or plaque * Often hyperkeratotic or ulcerated

Answer 15

* Invasion of dermis by atypical keratinocytes * Cells w/ nuclear pleomorphism, atypical mitosis and disordered maturation * Keratinocytes enlarged w/ abundant ground-glass eosinophilic cytoplasm * ± Polymorphous inflammatory infiltrate

Answer 16

* Most common type of skin cancer * Pearly erythematous papule w/ rolled border * Usu. on head and neck region * Long-standing lesions often large, locally destructive, and ulcerated ⇒ "rodent ulcer"

Answer 17

* **Malignant tumor arising from melanocytes** * Usually presents as: * Enlarging, irregularly pigmented macule, papule, or plaque * Asymmetric w/ irregular borders * ↑ Incidence and mortality rates of melanoma in recent decades * Early detection important in melanoma management

Answer 18

* Epidermis normal, atrophic or hyperplastic * Ulceration means worse prognosis * Asymmetrical proliferation of melanocytes * Often w/ poorly demarcated border * Atypical melanocytes * Small, spindled or epitheloid * Often finely dusted w/ melanin * Arise at dermal-epidermal junction * Invade the dermis * Pleomorphism, hyperchromatism, ↑ mitoses and ± prominent nuclei * Poor maturation of melanocytes * **Deeper cells are just as large and atypical as superficial one** * **Pagetoid spread** (or buckshot scatter) of melanocytes w/in epidermis * Lymphocytic infiltrate at base common * Depth of invasion into dermis ⇒ **Breslow’s thickness** * Most important prognostic factor

Answer 19

* ± Ulceration of epidermis * Basaloid tumor cells * Buds from epidermis or follicles or found w/in dermis * Variable atypia * Stroma often separates from tumor ⇒ Retraction artifact * Peripheral palisading of nuclei * Mucin in stroma or w/in basaloid aggregates

Answer 20

* Common benign fibrohistiocytic tumors of the skin * Firm dermal papules that “dimple” when the adjacent skin is compressed

Answer 21

* Epidermal hyperplasia * Flattened “tabled” rete ridges or basaloid proliferation * Hyperpigmented basal layer * Poorly circumscribed proliferation of boomerang-shaped spindled fibroblasts or histiocytes in the dermis * Often w/ whorled appearance * Large bundles of collagen (“**keloidal collagen**”) often present at periphery of lesion * Fibroblast around the bundles ⇒ **“collagen trapping”**

Answer 22

* Proliferative disorders of the skin involving cells whose progenitors arise elsewhere * Hone in to the cutaneous microenvironment

Answer 23

* **Primary cutaneous disorders that arises from lymphocytes** * **Mycosis fungoides (MF)** ⇒ most common type of CTCL * Accounts for ~ 50% of all primary cutaneous lymphomas * **Classical MF** ⇒ progress from patch stage → plaque stage → tumor stage * Long clinical course over years or even decades

Answer 24

* _Early lesions_ ⇒ band-like infiltrate of slightly atypical lymphocytes * Line up along the dermal–epidermal junction * _As lesions progress_ ⇒ **progressive epidermotropism of atypical lymphocytes** * Epidermotropism = lymphocytes residing in the epidermis * Often exhibits a peripheral halo * Numerous lymphocytes w/in the epidermis w/ minimal spongiosis * Focal collections of intraepidermal atypical lymphocytes ⇒ **Pautrier microabscesses** * Most specific finding * Only in 10% of lesions * Atypical lymphocytes sometimes have **cerebriform nucei** * _Tumor stage_ ⇒ less epidermotropism and atypical lymphocytes diffusely fill the dermis

Answer 25

* Transient skin or mucosal swellings due to plasma leakage * Wheals are characteristically pruritic and pink or pale in the center

Answer 26

* Epidermis normal * Dermal edema * Sparse perivascular and interstitial eosinophils, lymphocytes, PMNs and/or mast cells

Answer 27

* Diseases under umbrella category of "eczematous dermatoses" * Similar clinical and histological presentations * Eczema means to "boil over" and is synonymous w/ dermatitis * Spongiotic inflammation of the epidermis ⇒ common unifying characteristic

Answer 28

* Allergic contact dermatitis * Asteatotic dermatitis * Atopic dermatitis * Autosensitization (ID) reaction * Dyshidrotic eczema * Irritant contact dermatitis * Nummular dermatitis * Seborrheic dermatitis * Venous stasis dermatitis

Answer 29

* Hallmark is **spongiosis** ⇒ exocytosis of lymphocytes and intercellular edema * **± Spongiotic vesicle** (more likely if clinically acute) * Focal parakeratosis w/ ± crusting * PMNs in stratum corneum if secondarily impetiginized * Acanthosis or hyperkeratosis (more if clinically chronic) * Superficial perivascular lymphocytes, occasional eosinophils

Answer 30

* Most commonly associated w/ **herpes simplex virus (HSV) infection** * Typical clinical presentation includes "**target" lesions** * Oral mucosa, dorsal hands, or palms frequently involved * Episodes are recurrent and self-limited

Answer 31

* Necrotic keratinocytes * ± Spongiosis * Rarely intraepidermal vesicles * Basal layer liquefaction w/ ± subepidermal blister * Edema of the papillary dermis * Perivascular or interface lymphocytes, rarely w/ eosinophils

Answer 32

Inflammatory skin disorders that persist for many months to years

Answer 33

* Chronic disorder * Results from a polygenic predisposition combined w/ triggering factor * E.g. Trauma, infections or medications * **Sharply demarcated, scaly, erythematous plaques** * **± Sterile pustules** * Most common sites: * **Scalp, elbows and knees** * **Nails, hands, feet and trunk (including intergluteal fold)**

Answer 34

* **Confluent parakeratosis** * _PMNs in:_ * Stratum corneum ⇒ **Munro microabscesses** * Spinous layer ⇒ **spongiform pustules of Kogoj** * Hypogranulosis * Suprapapillary thinning of epidermis * Regular acanthosis, often w/ clubbed rete ridges * Dilated capillaries in dermal papillae * **Auspitz sign** ⇒ pinpoint bleeding if scale picked off * Perivascular lymphocytes

Answer 35

* **“Pruritic, purple, polygonal, planar papules and plaques”** of skin and mucosa * Fine reticulated scale over surface ⇒ **Wickham’s striae** * **Hep C** is more prevalent in pts w/ lichen planus vs controls

Answer 36

* **Compact hyperkeratosis** * No parakeratosis * **Hypergranulosis**, often wedge shaped * **Irregular acanthosis w/ “saw-toothed” rete ridges** * Colloid/civatte bodies * Dense, continuous infiltrate of lymphocytes along D-E junction * Liquefaction degeneration of the basal layer ⇒ ex. Of interface dermatitis * Melanin incontinence common

Answer 37

_Classified by:_ * Level of the blister * Subcorneal, intraepidermal, subepidermal * Type of inflammatory cells involved * PMNs, lymphocytes, eosinophils * Mechanism of blister formation * Spongiosis, acantholysis, balloon degeneration or epidermolysis

Answer 38

* **Intraepidermal vesiculobullous disorder** * Caused by auto-Ab directed at an intercellular keratinocyte adhesion protein ⇒ **Desmoglein 3** * Presents w/ flaccid bullae that break to form painful erosions

Answer 39

* **Split immediately above basal layer** * Leaves a “tombstone row” of basal keratinocytes * Tracking of separation down hair follicles ⇒ “follicular extension” * ± Eosinophils in spongiotic foci or blister cavity * Superficial lymphocytic inflammatory infiltrate in dermis * ± Eosinophils in dermal infiltrate * Direct IF (DIF) shows “net-like” deposition of IgG and C3 between keratinocytes in lower epidermis

Answer 40

* **Subepidermal vesiculobullous disorder** * Caused by auto-Ab to **bullous pemphigoid antigen I and/or bullous pemphigoid antigen II** * Presents with: * Tense bullae on normal or erythematous skin * Urticarial/eczematous lesions

Answer 41

* **Subepidermal bulla** * Eosinophils typically present w/in blister cavity * Early lesions ⇒ ± eosinophilic spongiosis * Exocytosis of eosinophils w/in a mildly spongiotic epidermis * **Direct IF of adjacent skin shows linear deposition of IgG and C3 along D-E junction**

Answer 42

* **Intensely pruritic vesiculobullous disorder** * Lesions common on elbows, knees, buttocks, and scalp * Caused by auto-Ab vs **epidermal transglutaminase-3** * Disease is highly correlated w/ **celiac sprue**

Answer 43

* **Subepidermal vesiculation** * Neutrophilic abscesses in tips of dermal papillae * Slight fibrin deposition in tips of dermal papillae @ points of vesiculation * Direct IF shows granular deposition of IgA w/in dermal papillae

Answer 44

* **Multifactorial disorder of the pilosebaceous unit** * Significant psychologic and economic impact * Clinical manifestations include comedones, papules, pustules, cysts and scarring * Characterized by: * ↑ Sebum production * Follicular hyperkeratinization * *Propionibacterium acnes* * Inflammation

Answer 45

* Follicular plugging * Frequently ruptured pilosebaceous apparatus w/ suppurative inflammation * Sometimes abscesses, sinus tracts and fibrosis

Answer 46

* **Inflammation of the subcutaneous fat** * Categorized into 2 groups: * “**Septal**” ⇒ primarily involves the septa separating lobules of fat * “**Lobular**” ⇒ primarily involves the lobules of fat themselves

Answer 47

* **Painful, erythematous subcutaneous nodules** * Usually distributed symmetrically over pretibial areas; occasionally elsewhere * Later stages ⇒ lesions acquire a bruise-like appearance * ± Fever, arthralgias and malaise * **Associated w/ a wide variety of systemic disorders**

Answer 48

* Septal panniculitis of lymphocytes, histiocytes, PMNs and/or eosinophils * Older lesions: * Multinucleated giant cells * Septal fibrosis

Answer 49

“Warts” * **Caused by human papillomavirus (HPV)** * Ubiquitous DNA virus * Over 100 HPV subtypes * Different subtypes tend to produce different clinical lesions * Immunocompromised patients may have larger or more intractable warts

Answer 50

* Hyperkeratosis, papillomatosis, hypergranulosis * Columns of parakeratosis * Especially over projecting dermal papillae * Vacuolated superficial keratinocytes w/ pyknotic raisin-like nuclei ⇒ **koilocytes** * Rete ridges shaped inward @ borders of lesion * Dilated capillaries in dermal papillae * Perivascular lymphocytes

Answer 51

* Caused by a DNA poxvirus of the *Molluscipox* genus * Mainly a disease of children * Can affect immunocompromised adults * Produces smooth, dome-shaped, umbilicated papules

Answer 52

* **Common superficial infection w/ *Staph aureus* and/or *Strep pyogenes*** * Most common in children * Plaques of honey-colored crust

Answer 53

* Early lesions ⇒ subcorneal pustule filled w/ PMNs ± acantholytic cells * Spongiosis common * Established lesions ⇒ crust composed of serum, PMNs and parakeratotic material * Gram-⊕ cocci usually found in crust * Gram stain and culture may be required

Answer 54

* Caused by superficial fungi * Further subclassified based on area of the body affected * Most tinea infections are characterized by: * Intensely pruritic, annular lesions * Peripheral scale * Central clearing * Variable inflammation

Answer 55

* ± PMNs in the stratum corneum * Parakeratosis common * Fungal hyphae in stratum corneum or follicles * Sometimes visible w/ H&E * Best seen w/ Periodic Acid–Schiff (PAS) stain * Rich in mucopolysaccharides ⇒ stain bright pink to red * Variable inflammatory response * Skin may appear “normal” * Culture of material scraped from these areas will usu. allow ID of offending species

Answer 56

* **Superficial infection of the epidermis caused by commensal yeast of genus *Pityrosporum*** * Some use the genus *Malassezia* to refer to the pathogenic hyphal phase of this normal skin commensal * Particularly common in young adults living in warm and humid climates * Hypopigmented or brownish-red, slightly scaly patches * Most common on the trunk