Skin cancer

Question 1

What is a solar keratosis and what are it’s histological features?

Answer 1

• premalignant dysplastic lesion caused by sun exposure to the skin
• exhibit hyperkeratosis and parakeratosis with basal cell layer atypia and epithelial hyperplasia
• less than 1cm diameter, tan brown, red or skin coloured, rough, sandpaper consistency.
• may resemble a horn

Question 2

How are solar keratoses treated and why?

Answer 2

• Likely to become malignant SCC, so excised by cutterage,

cryotherapy

Question 3

What is the difference between a solar keratosis and SCC in situ?

Answer 3

In solar keratoses, nuclear atypia are only in the basal layer of keratinocytes. In SCC in situ, atypia are in all layers of the epidermis.

Question 4

What is Bowen’s disease?

Answer 4

Squamous cell carcinoma in situ

Question 5

● A 65-year-old farmer presents with a raised crusted lesion on the dorsum of his left hand
● On examination the skin is sun-damaged with numerous solar keratoses
● The lesion is raised and indurated and tender when slight pressure is applied

Likely diagnosis?

Answer 5

Squamous cell carcinoma

Question 6

What are the histological features of squamous cell carcinoma?

Answer 6

• Invasion through the deromo-epiderman junction (distinguishes from SCC in situ)
• cells with atypical (enlarged and hyperchromatic) nuclei involve all levels of the epidermis
• . Invasive squamous cell carcinoma shows variable degrees of differentiation, ranging from tumors composed of polygonal cells arranged in orderly lobules and having numerous large areas of keratinization, to neoplasms consisting of highly anaplastic cells that exhibit only abortive, single-cell keratinization (dyskeratosis).

Question 7

What % of skin SCCs metastasise to LNs?

Answer 7

2%

Question 8

What are the risk factors for SCC?

Answer 8

Solar radiation, X-irradiation, Arsenical

compounds, Immunosuppression

Question 9

What % of SCCs from the lips or ear metastasise?

Answer 9

10%-15% from lip or ear metastasize

Question 10

What is a factor that makes prognosis of SCC worse?

Answer 10

Immunosuppression

Question 11

What is a Keratoacanthoma?

Answer 11

Keratoacanthoma (KA) is a low grade variant of SCC. It is a relatively common low-grade tumor that originates in the pilosebaceous glands and closely resembles squamous cell carcinoma (SCC). They appear as an elevated crater filled with keratin, and regress spontaneously, but are often treated surgically because it can be difficult to distinguish them from SCC.

Question 12

A 54-year-old Caucasian male with a long history
of sun exposure and multiple episodes of sunburn
presents with a skin lesion on his lower eyelid
● The lesion has raised “pearly” edges and a central
depression
● He gives a history of recurrent crusting of the
lesion followed by loss of the crust and apparent
“healing”
Likely diagnosis?

Answer 12

BCC

Question 13

What are the three presentations of BCC and what do they look like?

Answer 13

Nodular basal cell carcinoma:
Basal cell carcinomas usually present as pearly papules containing prominent dilated subepidermal blood vessels ( telangiectasias ) ( Fig. 25-15 A ). Some tumors contain melanin and superficially resemble melanocytic nevi or melanomas. Advanced lesions may ulcerate, and extensive local invasion of bone or facial sinuses may occur after many years of neglect or in unusually aggressive tumors.

Superficial BCC:
presents as an erythematous, occasionally pigmented thin plaque. Dry and scaley, often eroded and crusting.

Morphoeic BCC
Morphoeic or sclerosing BCC is hard to identify (a scar-like plaque or dent) and often deeply invasive. It is most often found on the mid-face.

Question 14

What are the histological features of BCC?

Answer 14

Nests of uniform basaloid cells within the dermis that are often separated from the adjacent stroma by thin clefts.

Cohesive nests of basaloid tumour cells (sometimes with a small amount of squamous differentiation)

Peripheral palisading of nuclei at the margins of cell nests

Retraction artefact (clefts) around cell nests

Variable inflammatory infiltrate and ulceration basophilic cells with hyperchromatic nuclei, embedded in a mucinous matrix, and often surrounded by many fibroblasts and lymphocytes ( Fig. 25-15 B ). 

The cells at the periphery of the tumor cell islands tend to be arranged radially with their long axes in parallel alignment (palisading) . In sections, the stroma retracts away from the carcinoma ( Fig. 25-15 C ), creating clefts or separation artifacts that assist in differentiating basal cell carcinomas from certain appendage tumors that are also characterized by proliferation of basaloid cells, such as trichoepithelioma. )

Question 15

Is BCC locally agressive?

Answer 15

Yes

Question 16

Do BCCs often metastasise?

Answer 16

No- basically never.

Question 17

What are some ddx of a pigmented skin lesion?

Answer 17

• melanocytic lesions (benign and malignant)
• vascular lesions
• basal/ squamous lesions with pigment (such as pigmented BCC or Seborrhoeic Keratosis)
• fibrohistiocytic lesions

Question 18

What is a Seborrhoeic Keratosis? What are their macroscopic and microscopic features?

Answer 18

• pigmented benign lesions= ‘senile/brown warts’
• They begin as slightly raised, skin coloured or light brown spots. Gradually they thicken and take on a rough, warty surface. They slowly darken and may turn black. Well circumscribed, no dermal induration/ tenderness, may bleed if subjected to mechanical disturbance.
• Histology: ‘stuck on’ above the level of the surrounding epidermis. Proliferation of basaloid cells without pleomorphism/ atypia. Horn cysts. No dermal invasions.Hyperkeratosis, papillomatosis, acanthosis
  Basaloid keratinocytes
  Horn cysts
  Abundant melanin in basal layer or throughout epidermis
  Sharp demarcation of base of epidermal hyperplasia
  Largely located above the surrounding epidermis
  Irritated seborrhoeic keratoses may show many features suggestive of malignancy, and can be difficult at times tdifferentiate from squamous carcinoma

Question 19

What is this?
They appear as firm-feeling nodules, often yellow-brown in colour, sometimes pink and sometimes quite dark, especially in dark coloured skin. If the skin over a the nodule is squeezed a dimple forms, indicating tethering of the skin to the underlying fibrous tissue.

Answer 19

Dermatofibroma (fibrous histiocytoma)
A dermatofibroma is also sometimes called a fibrous histiocytoma. It is due to a non-cancerous growth of dermal dendritic histiocyte cells. In some cases it arises at the site of a minor injury, especially an insect bite or thorn prick. The cause is unknown; whether it is due to a neoplasm or reactive process is debated.

Question 20

What is a haemangioma?

Answer 20

Haemangioma describes a benign (non-cancerous) overgrowth of blood vessels in the skin. Angiomas are due to proliferating endothelial cells; these are the cells that line blood vessels.

Angiomas include:

Cherry angioma
Spider angioma (spider naevus)
Venous lake

Question 21

What is a junctional naevus?

Answer 21

• Earliest form of melanocytic naevi. Grossly, lesions are small, relatively flat, symmetric and uniform.
• nests of round cells that grow along the dermoepithelial junction (originating at the tips of rete edges)
• Nuclei of nevus cells are uniform and rounded in contour, contain inconspicuous nucleoli, and show little or no mitotic activity.

Question 22

What is a compound naevus?

Answer 22

In contrast to the junctional nevus, the compound nevus (A) is raised and dome-shaped. The symmetry and uniform pigment distribution suggest a benign process. Histologically (B), compound nevi combine the features of junctional nevi (intraepidermal nevus cell nests) with nests and cords of dermal nevus cells.

Question 23

What is an intradermal naevus?

Answer 23

Epidermal nests are lost entirely and all the nests and cords are in the dermis. (more raised)

Question 24

In regards to which kind of skin cancer is a family history very important?

Answer 24

Melanoma (dysplastic naevus syndrome, 50% chance of melanoma by 60yo)

Question 25

● 48-year-old male
● Itchy pigmented lesion on back
● Noticed by partner to have increased in size
and pigmentation over the past 2 months
● Not aware of the lesion being present 12
months ago

Likely diagnosis?

Answer 25

Melanoma

Question 26

What are 7 important symptoms suggestive of melanoma?

Answer 26

Itch
Bleeding/ crusting
Inflammation (swelling, heat, erythema, tenderness)
Size
Increasing size
Poorly defined, irregular and notched borders.
Colour variation (shades of black, brown, red, dark blue, and gray)

Question 27

What is the histological appearance of melanoma?

Answer 27

Haphazardly distributed atypical melanocytes present as single cells and nests at all levels of the epidermis.

Histologically, melanomas are asymmetrical and poorly circumscribed lesions with architectural disturbance and usually marked cytological atypia. Specific features include consumption of the epidermis, pagetoid spread of melanocytes, nests of melanocytes with variable size and shape (which may be confluent and lack maturation), melanocytes within lymphovascular spaces, deep and atypical mitoses and increased apoptosis. Ulceration, if present, is a poor prognostic factor. Mitotic figures are common.

Question 28

Which layer of epidermis are melanocytes usually located in?

Answer 28

Stratum basale

Question 29

What is the most powerful prognostic factor for melanoma?

What is the rating system?

Answer 29

Depth of invasion
Clark level:

Clark level	Level of invasion
1	Epidermis (in-situ melanoma)
2	Papillary dermis
3	Papillary/reticular dermal interface
4	Reticular dermis
5	Subcutis

OR Breslow thickness:
depth from the granular layer of the epidermis to the deepest part of the tumour

Question 30

What are the important prognostic factors for melanoma (12)?

Answer 30

Increased age	
Increased Breslow thickness
Site: back, upper arm, neck, scalp	
Vertical growth phase
Males	
Ulceration 
Maori and Pacific Islanders	
Lymphovascular and perineural invasion
Increased mitotic rate
Regression 
Tumour infiltrating lymphocytes 
Microsatellitosis