Chapter 3

Question 1

True or false:

According to Elston, “crushing of the basal layer is less likely seen in melanoma.”

Answer 1

True

(See YouTube videoon Chapter 3)

Question 2

What are the histologic findings of a fibroepithelioma of Pinkus? (4)

Answer 2

1. Anastamosing pink strands with
2. Eccrine ducts with
3. blue buds at tips surrounding a
4. fibromyxoid stroma

Question 3

When evaluating the margins of a superficial BCC, where do you look? (2)

Answer 3

Aside from looking for tumor in the epidermis, make sure there is no tumoral fibromyxoid stroma at the margins in the dermis

Question 4

What are histologic features of keratoacanthoma (KA)?

Answer 4

1. Crateriform
2. No acantholysis (an absolute disqualifier for KA)
3. Hypergranulosis (beginning at hair follicles) toward the center of the lesion (whereas in SCCs, hypergranulosis is only at the lesion periphery)
4. Amphophilic elastic fiber trapping (“KAs pull their way into the epidermis along elastic fibers”)
5. Neutrophil microabscesses
6. Eosinophils usually present (whereas plasma cells are more typically present in SCCs)

Question 5

What does amphophilic mean?

Answer 5

That which can be stained with either an acid or basic dye (bluish-red color)

See Paget cells with abundant amphophilic, clear cytoplasm in image

Question 6

What immunostains could you use to stain an invasive SCC? (5)

Answer 6

1. Pankeratin
2. p63 (nuclear stain)
3. P40 (subtype of p63)
4. AE1 and AE3 (mix of low- and high- molecular weight keratins)
5. Keratin 903 (high molecular weight keratin)

Question 7

What can the stain BerEP4 be used for?

Answer 7

A marker of BCC

Question 8

What skin lesions have Pagetoid spread? (at least 4)

Answer 8

1. Bowen’s disease
2. Paget’s disease (PAS with diastase positive)
3. Sebaceous carcinoma (EMA positive in a vacuolar pattern)
4. Melanoma (S100)

Question 9

What is trichilemmal keratinization?

Answer 9

Keratinizing abruptly WITHOUT a granular layer

Question 10

What are the histologic findings of a proliferating pilar cyst (a.k.a. proliferating trichilemmal cyst or pilar tumor)?

Answer 10

Rolls and scrolls of keratinizing squamous epithelium

Question 11

What is the “flag sign” for actinic keratoses?

Answer 11

Alternating ortho- and para-keratosis

Orthokeratosis appears at the acrosyringia and acrotrichia

Parakeratosis overlies the abnormal epidermis

Can sometimes be seen with Bowen disease

Question 12

Where do you see the “eyeliner sign”? (2)

Answer 12

1. Bowen’s disease
2. Paget’s disease

Question 13

What are the histologic features of micronodular BCC?

Answer 13

Palisaded blue islands with clear spaces

Round ovoid islands at the deep aspect that are between collagen bundles

Question 14

When pagetoid spread “spits out” into the cornified layer, what two diagnoses may this suggest?

Answer 14

1. Paget’s disease
2. Melanoma

This suggests AGAINST Bowen’s disease.

Question 15

What is suggested by the following:

Cells spitting out into corneum

Crushing of basal layer

Amphophilic cells

Answer 15

Paget’s disease

Question 16

According to Elston, how can you tell between a clonal SK and clonal Bowen’s disease?

Answer 16

• Look at the nuclear envelope (the single best discriminator)
• “In the squamous world, number of mitoses and pleiomorphism does not help you determine malignant or benign.”
• Malignant squamous cells may have a nuclear envelope that is thick, refractile, glassy, notched, and/or corrugated
• Benign squamous cells are oval and may have a delicate nuclear envelope (+/- multiple nucleoli, red nucleoli, or red mitoses)

Question 17

Are acantholytic cells spindled?

Answer 17

“They tend to ROUND UP with acantholysis.”

Spindling usually requires desmosome attachments to stretch out the cell into a spindled shape.

Question 18

What features may suggest HPV-induced (genital) Bowen’s disease?

Answer 18

Hypergranulosis

Compact horn with small, “cookie cutter” holes

Keratinocytes tend to be smaller than in other Bowen’s disease

Question 19

What are histologic findings of infundibulocystic BCC? (3)

Answer 19

1. Pink islands with blue buds
2. Horn cysts
3. Radiating outward from central follicular-like structures

Question 20

What are the two “pink strand, blue bud tumors”?

Answer 20

1. Fibroepithelioma of Pinkus (strands anastomose like a net with lumps of stroma in between)
2. Infundibulocystic BCC (finger-like projections radiating outward into stroma)

Question 21

How does the parakeratosis of an actinic keratosis versus a wart compare?

Answer 21

Actinic keratosis parakeratosis usually thin and flat

Wart parakeratosis is usually round

Question 22

When trying to discriminate between Bowen’s disease and Paget’s disease, what stain for ducts may be useful?

Answer 22

Mucicarmine

Stains ducts and can visualize an underlying adenocarcinoma

Question 23

What are the histologic findings of a trichoblastoma? (4)

Answer 23

1. Lack of retraction space from stroma
2. Palisading collections of blue cells
3. Stroma is NOT fibromyxoid (which has a bluish hue and cell-poor) but instead is concentric and fibroblast-rich (like the follicular sheath)
4. Papillary mesenchymal bodies in stroma

“The epithelium will look like a BCC but look at the stroma.”

Question 24

What would be your stain choices for a desmoplastic SCC? (2)

Answer 24

• Keratin 903
• p63
• Note: pankeratin may be negative