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Book - Molavi > Chapter 27 - Skin > Flashcards

Chapter 27 - Skin Flashcards

1
Q

Describe the morphology of melanocytes

A

Neuralish, dendritic morphology and stain with S-100. Also produce melanin pigment but do not carry much themselves.

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2
Q

What is a melanophage?

A

A spindly mancrophage which appears melanotic because they are consuming melanin.

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3
Q

Desecribe the normal course of a melanocytic nevus.

A

Begins as a lentigo simplex at the dermoepidermal junction. Proliferates into nests (theques) as a junctional nevus. Then migrates into the dermis with loss of the junctional component (intradermal nevus).

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4
Q

What is a compound nevus?

A

A junctional nevus with a dermal component.

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5
Q

Recall some benign or reassuring features of nevi.

A

Symmetry

Size <3mm

Lateral borders consisting of nests (not individual cells)

Lack of atypia

Maturation into the dermis

Chunky brown-black pigment

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6
Q

What is a blue nevus?

A

A common nevus consisting of a diffuse scattering of dendritic single melanocytes mixed with melanophages.

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7
Q

What is a Spitz nevus?

A

A cirumscribed and symmetric nevus found on the head & neck of children.

Melanocytes may be large, spindled, pleomorphic, or even show mitoses. Look for eosinophilic Kamino bodies.

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8
Q

What are some features of acral & genital nevi?

Of congenital nevi?

A

Acral and genital nevi are allowed some atypical features (pagetoid spread, lengitinous growth), but no cytologic atypia.

Congenital nevi should track down the adnexal structures.

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9
Q

What are the four features of architectural disorder in dysplastic nevi?

A

Lentiginous spread of atypical melanocytes (along DEJ)

Shouldering (lentiginous component wider than dermal component)

Bridging of rete (nests attached to adjacent rete ridges fuse)

Fibroplasia (featuring of dermal collagen)

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10
Q

What are the four features of cytologic atypia in dysplastic nevi?

A

Hyperchromatic nuclei (increased N:C)

Large red nucleoli

Accumulation of dusty grey-brown melanin

Atypical mitoses

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11
Q

What is lentigo maligna?

What is Melanoma in situ?

A

Lentigo: Malignant melanocytes proliferating only along the DEJ.

In situ: Above, and percolating up through the epidermis in a pagetoid fashion

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12
Q

What feature is required to diagnose malignant melanoma?

Distinguish between superficial spreading and nodular melanomas.

A

Invasion through the DEJ into the dermis (and pagetoid epidermal spread)

Superficial spread grows horizontally but also involves the dermis. Nodular is primarily growing down into the dermis.

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13
Q

Recall some morphologic feature suspicious for melanoma.

A

Asymmetry

Discohesive nests

Discohesive cells & pagetoid spread

Band-like associated lymphocytes

Cytologic atypia

Lack of deep maturation

Melanocytic necrosis

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14
Q

What criteria must be included on sign out of a melanoma?

A

Depth (Breslow’s in hundredth of a millimeter, Clark’s related to the histologic levels)

Presence or absence of ulceration

Margin status

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15
Q

What are desmoplastic and spindle cell melanoma?

A

Melanoma with spindly/sarcomatoid melanocytes. Desmoplastic is also sparsely cellular in a dense fibrotic background. Look for clumps of lymphocytes…

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16
Q

What is acral lentiginous melanoma?

A

A melanoma that is characterized by prominent lengitinous growth, and can be hard to distinguish from an acral nevus.

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17
Q

What features of metastatic lesions suggest melanoma?

A

Alveolar (nested) architecture

Large cells with big nuclei and red nucleoli

Occasional melanin pigment

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18
Q

Recall the utility of S-100, HMB-45, and Melan-A in diagnosis of melanoma.

A

S-100 stains all melanomas. Not helpful in lymph nodes (FDCs)

HMB-45 does not stain spindled melanomas. Generally lost deep in a melanoma. Also stains PEComas & angiomyolipoma.

Melan-A does not stain spindled or desmoplastic melanomas.

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19
Q

What is solar elastosis?

Solar lentigo?

A

Elastosis: Accumulation of grey wispy damaged elastin in the dermis

Lentigo: A finger-like proliferation of hyperpigmented rete growing into the epidermis.

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20
Q

What are the defining features of actinic keratosis?

A

Squamous atypia of varying thickness

Keratin becomes pink and hyperkeratotic, with sparing of keratin above the hair follicles.

Underlying solar elastosis

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21
Q

What is bowenoid actinic keratosis?

A

Full-thickness atypia without invasion.

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22
Q

What dermal entities can be categorized as carcinoma in situ?

A

Actinic keratosis & bowenoid actinic keratosis

Bowen’s disease: In non sun-damaged skin and does not spare hair follicles

Bowenoid papulosis: HPV-related lesion of genital sites

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23
Q

What are the features of basal cell carcinoma?

A

Lobules of small, blue, basal-type keratinocytes with peripheral palisading

Formation of clefts between tumor nests and stroma

Desmoplasia, focal keratinization, or mucin production

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24
Q

Recall three or so subtypes of basal cell carcinoma.

A

Nodular: Usual type

Superficial multicentric: Hangs off epidermis like stalactites

Sclerosing: Prominent desmoplastic response

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25
Q

Describe the usual morphology of seborrheic keratoses.

A

Hyperkeratotic, orthokeratotic lesion with a markedly thickened epidermis. Features horn cysts (whorls of orthokeratin) and some pigment and inflammation. No atypia.

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26
Q

Describe the morphology of verruca vulgaris.

A

Church-spire epidermal proliferation with overlying hyper/parakeratosis. Has koilocytes.

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27
Q

What are eccrine poroma / acrospiroma / hidradenoma?

A

Tumors of sweat ducts composed of keratinocyte-like cells tha tform ducts. Streamy, pale, and disorganized. Like usual ductal hyperplasia in breast.

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28
Q

What are eccrine spiradenomas?

A

“Blue cannonballs in the dermis”, consisting of two basaloid cell lineages with noticeable cords and droplets of hyaline basement membrane substance

29
Q

What is a cylindroma?

What is a syringoma?

A

An adnexal tumor with basaloid nests in the dermis but a mosaic shape to the nests.

A collection of round, dilated tubules with tadpole-like appearance

30
Q

What is a trichoepithelioma?

What is microcystic adnexal carcinoma?

A

A benign tumor of hair follicle that resembles BCC but with horn cysts, hair formation, fibrotic stroma and lack of clefting.

A cancer of sweat gland that resembles syringoma but with deep infiltration into the dermis.

31
Q

What is an epidermoid cyst?

What is a pilar cyst?

A

Epidermoid: Lined by mature squamous epithelium with a granular layer and filled with flaky keratin.

Pilar: Lined by plump keratinocytes with no granular layer filled with compact dense keratin.

32
Q

Describe the normal morphology of dermatofibroma.

What is its malignant counterpart?

A

Ill-defined blue haze in the dermis made of tiny swarming nondescript cells with overlying hyperpigmentation/hypertrophy.

Dermatofibrosarcoma protuberans

33
Q

Describe the normal morphology of neurofibromas.

A

Pale/grey nodules in the dermis composed of cells with wavy nuclei and wavy collagen.

34
Q

Describe the normal morphology of hemangiomas.

What is its malignant counterpart?

A

Proliferation of well-formed, dilated capillaries in teh dermis.

Angiosarcoma, which is more cellular and has anastomosing channels lined with plump cells.

35
Q

Describe the morphology of Kaposi’s sarcoma.

Of pyogenic granuloma?

A

Simulates hemangioma, very hard to spot in early stages.

Lobular, circumscribed lesion that is very cellular and inflamed.

36
Q

How does the epidermis appear folowing acute damage or inflammation?

A

Edema (spongiosis), which can be severe enough for form intradermal vesicles. Followed by hyperplasia (acanthosis) and possibly hyperkeratosis.

37
Q

What is interface dermatitis, and what are its two patterns?

A

Inflammation of the basal keratinocyte layer.

Lichenoid: Intense lymphocytic infiltrate at the DEJ.

Vacuolar: Vacuolar degeneration of the basal cells

38
Q

What is acantholysis?

A

Usually antibody-mediate destruction of the intercellular junctions. Results in coalescence of bullae.

39
Q

What is the most simple pattern of dermal inflammation?

What if it progresses and features neutrophils?

A

Perivascular lymphocytic inflammation

Vasculitis

40
Q

What is leukocytoclastic vasculitis?

A

Vessels show fibrinoid necrosis and nuclear debris

41
Q

What do neutrophilic infiltrates, granulomas, or dense lymphocytic infiltrates in the dermis suggest?

A

Neutrophilic: eg Sweet’s syndrome

Granulomatous: Infection, foreign body response, sarcoidosis, granuloma annulare

Lymphocytes: Consider cutaneous T-cell lymphoma

42
Q

What are the two forms of panniculitis? Give examples.

A

Septal: Inflammation is mostly in the fibrous septae between fat. eg Erythema nodosum.

Lobular: Fat itself is inflamed. eg Lupus profundus.

43
Q
A

Normal skin

  1. Normal melanocyte with clear halo of cytoplasm
  2. Pigmented basal keratinocyte
  3. Typical orthokeratin
44
Q
A

Melanophages in an intradermal nevus

Arrowhead: Nevus cells
Arrow: Melanophages

45
Q
A

Lentigo simplex in acral skin

Arrows: Linear proliferation of melanocytes along DEJ.

46
Q
A

Compound nevus

Arrow: Nest of nevocellular cells at the DEJ
Arrowhead: Maturing nevus cells in the dermis

47
Q
A

Intradermal nevus

More mature cells at base (arrowhead) than at surface (arrow).

48
Q
A

Blue nevus

Arrow: Elongated, fusiform cells scattered in dermal collagen

49
Q
A

Spitz nevus

Arrow: Large, spindled melanocytes at the DEJ
Arrowhead: Pagetoid spread of melanocytes in the epidermis

50
Q
A

Dysplastic nevus

Arrow: Spindled melanocytes bridging the rete
Arrowhead: Trailing of single melanocytes at the edges
Inset: Cytologicallya typical melanocytes

51
Q
A

Melanoma

Top: Pagetoid spread of melanocytes (arrowheads)

Bottom: Deep dermal melanocytes with cytologic atypia (arrowhead) and mitoses (arrow).

52
Q
A

Desmoplastic melanoma

Arrow: Appearance of hypocellular scar in dermis
Arrowhead: Collection of lymphocytes
Inset: Enlarged and hyperchromatic melanocytes within the “scar”

53
Q
A

Solar elastosis

Arrow: Collagen replaced by gray-blue strands of elastin

54
Q
A

Solar lentigo

Arrow: Prominent rete with increased basal pigmentation and underlying solar elastosis

55
Q
A

Actinic keratosis

  1. Disorganized and enlarged nuclei
  2. Atypical mitoses
  3. Overlying hyperkeratosis/parakeratosis
  4. Underlying solar elastosis
56
Q
A

Squamous cell carcinoma

Left: Superficially invasive SqCC
Arrow: Deep keratinization (invasive nest)
Arrowhead: AK-like changes in the overlying epidermis

Right: Same, high-power
Asterisk: Keratin pearl
Arrow: Infiltrating single cell

57
Q
A

Basal cell carcinoma

Arrow: Clefting of tumor cells from the stroma
Arrowhead: Prominent palisading at periphery of nests

58
Q
A

Seborrheic keratosis

Arrow: Horn cysts (entrapped keratin)
Arrowhead: Hyperkeratosis (but no parakeratosis!)

59
Q
A

Verruca vulgaris

Arrow: Epidermis heaped into tall spires, topped with hyperkeratosis and parakeratosis.

60
Q
A

Poroma

Arrow: Epidermis, continuous with lesion
Arrowhead: Tumor cells that are uniform, small and round, sometimes with rudimentary duct spaces

61
Q
A

Eccrine spiroadenoma

“Cannonballs in the dermis” composed of small round bland cells. Cords of hyaline pink basement membrane material (arrow).

62
Q
A

Syringoma

Arrow: Small tubules with comma-like tails in the dermis

63
Q
A

Microcystic adnexal carcinoma

Arrow: Horn cysts
Arrowheads: Small pale nests deeply infiltrating the dermis

64
Q
A

Left: Trichilemmal cyst (no granular cell layer, dense “wet” keratin)

Right: Epidermoid cyst (granular cell layer, flaky “dry” keratin)

65
Q
A

Dermatofibroma

Arrowheads: Poorly circumscribed blue haze of fibroblasts
Arrow: Overlying prominent and hyperpigmented rete
Inset: Infiltrating cells with small round-to-oval nuclei.

66
Q
A

Dermatofibrosarcoma protuberans

Note increased cellularity and prominent storiform architecture

67
Q
A

Neurofibroma

Arrowhead: Poorly defined dermal tumor that is paler than surroundings
Inset: Tapering, undulating nuclei (arrow) and wavy collagen fibers (arrowhead)

68
Q
A

Capillary hemangioma

Note collection of discrete, well-formed and dilated capillaries

69
Q
A

Kaposi’s sarcoma

Arrowheads: Slit-like vascular spaces with bland endothelium
Arrow: Accentuation of spaces around existing vasculature (“promontory sign”)

Book - Molavi (29 decks)

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