PATHOLOGY- Common skin cancers Flashcards
Name some common skin cancers
- Basal cell carcinoma a
- Squamous cell carcinoma
- Melanocytic tumours
Name the different layers of the epidermis
- Basil cell layer
- Prickle cell layer
- Granule cell layer
- Keratinsed squames
Name the 3 main parts of the skin
- Epidermis
- Dermis
- Subcutaneous layer
Name some specialised cells in the epidermis
- Melanocytes
- Merkel cell
- Dividing cell
- Langerhan cell (immune cell)
What do melanocytes do?
They produce melanin
Name some cancers that can form in the epidermis of the skin
- Squamous cell carcinoma
- Basal cell carcinoma
- Melanoma
- Merkel cell carcinoma (quite rare)
What are benign glandular tumours called
Adenomas
What are malignant glandular tumours called
Carcinomas
Name some elements of the skin where skin tumours can arise from
- Epidermis
- Melanocytes
- Merkel cell tumours (Rare but dangerous)
- Adnexal structures (like sweat glands and hair follicles)
- Nerves and blood vessels
- Connective tissue
Where do basal cell carcinomas usually form
On EXPOSED hair bearing skin such as on the face and lips (apart from hands)
Name the most common malignant tumour humans can develop
Basal cell carcinomas (BCC)
Define metastases
the development of secondary malignant growths at a distance from a primary site of cancer.
How often do metastases form in basal cell carcinomas
Very rarely (1 in 10,000)
Why are basal cell carcinomas problematic?
As they can be locally aggressive and spread from the epidermas down to subcutaneous fat and the nerve and bone area
List the key risk factors for developing basal cell carcinomas
- UV light exposure (especially in pale individuals)
- Immunocompromised patients
Talk through the aetiology of basal cell carcinomas
- Prominently form on sun exposed sites, especially the face
- Pale skinned individuals who burn easily are at greater risk
- Immunosuppression
- Rare genetic predisposition (goblin syndrome and bazex)
What is gorlins syndrome
An autosomal dominant syndrome where the tumour suppressor genes are mutated
List some characteristics of goblin syndrome
- Palmar pits
- Odontogenic keratocytes
- Skeletal abnormalities
- Mental retardation
- Brain tumours
What do early lesions of basal cell carcinomas look like?
Nodules on the skin
If nodules on the skin (caused by BCCs) are neglected and left untreated what can happen?
They can begin to ulcerate with rolled edges
this is called a rodent ulcer
Why is the histology of basal cells carcinomas split into different types and name the 2 types of BCC histology
They are split as there’s a lot of variants
- Low risk types
- High risk types
What are basal cell carcinoma tumours made up of
Tumours composed of islands of basaloid cells with peripheral palisade
Describe the low risk histology of basal cell carcinomas
Superficial and nodular
Describe the high risk histology of basal cell carcinomas
Infiltrative, micro-nodular and morphoeic
Name the second most common skin cancer
Squamous cell carcinoma
Which is more aggressive Basal cell carcinomas or squamous cell carcinomas
squamous cell carcinomas
Name the high risk sites where squamous cell carcinomas are more likely to form
Lip
Ear
Perineum
How often do metastases form in squamous cell carcinomas
0.5-5%
List the risk factors associated with developing squamous cell carcinomas
- UV exposure
- Immunosuppressed individuals
- Patients with chronic ulcers
- Radiation burns
- Chemotherapy drugs
Describe the aetiology of squamous cell carcinomas
- UV radiation
- Radiotherapy
- Chronic scars/ ulcers
- Immunosuppression
- Drugs for melanoma
Describe the clinical presentation of early squamous cell carcinomas
Nodules ulcerated with a crusty surface
Describe how squamous cell carcinomas look under a microscope
They look like invasive islands and trabecular of squamous cells showing cytological atypia
What are carcinomas
Malignant glandular tumours
What are adenomas
Benign glandular tumours
Where do squamous cell carcinomas usually metastasise to?
Lymph nodes first
Name the pre invasive stage that occurs before a squamous cell carcinoma forms?
Actinic keratosis
What is actinic keratosis
A pre malignant change seen due to prolonged UV exposure
Describe actinic keratosis
- Dysplasia to squamous epithelium
- Can lead to the formation of a scaly lesion with erythematous base
- Rarely progresses to invasive disease
Where do actinic keratosis usually form?
Very common on chronic sun exposed sites
Where are melanocytes derived from
Derived from neural crest cells
What is the function of melanocytes?
To form melanin which is transferred to epidermal cells to protect the nucleus from UV radiation
Name the tumours melanocytes can give rise to?
Naevi (benign moles)
Melanoma (malignant)
Describe naevi
They are local benign collections of melanocytes
Name the different types of naevi
- Superficial
- Deep blue naevi
Name some types of deep blue naevi
- Mongolion spot
- Naevi of Ota, Ito and Hori
How are superficial naevi classified?
By their location
Name some different classifications of superficial naevi
- Junctional naevi
- Intra dermal naevi
- Compound naevi
Where are junctional naevi found
At the base of the epidermis at the junction
Where are intra dermal naevi found?
Found entirely in the dermis
Where are compound naevi found
The naevi has nests in both the dermis and the junction
How do deep blue naevi form
Melanocytes that have been migrating from the neural crest to the epidermis haven’t made it and sometimes form masses Called naevi
How do we name deep naevi
By their morphological, macroscopic description
In whom might you see deep naevi
Mainly in children but they often resolve over time
What are the main problems associated with giant congenital naevi?
Aesthetics is the major problem especially if the naevi covers a large area
(very rarely do these naevi turn malignant)
What is atypical mole syndrome
People with a large number of clinically atypical moles
Describe atypical moles
Moles with irregular margins and that are greater than 1cm in diameter
Variations in colour
What are people with atypical mole syndrome more likely to develop
Increased risk of developing melanomas
What can atypical mole syndrome sometimes me caused by?
Due to mutations in gene CDKN21 (p16)
What is the significance of the p16 gene
It is a key tumour suppressor gene
Which tumour is the rarest:
- Basal cell carcinoma
- Squamous cell carcinoma
- Melanomas
Melanomas
Why are melanomas dangerous
As they can metastasize widely
What are naevi?
Benign moles that arise from melanocytes
What are melanomas
Malignant tumours that arise from melanocytes
Why are the instances of melanomas rising?
More foreign travel
List some the risk factors for melanomas
- UV exposire
- Tend to arise in people with pale skin
- Personal or family history of malignant melanomas
- Giant congenital naevi
Describe the aetiology of melanomas
- Sun exposure (especially short intermittent severe exposure)
- Race (fair complexion red hair etc)
- Family history of atypical mole syndrome and multiple large atypical moles
- Giant congenital naevi have. small risk in turning malignant (<5%)
What is the probability that a giant congenital naevi will turn malignant?
less than 5%
In terms of sun exposure and the risk of developing melanomas which is worse:
- Long periods of exposure
- Short rare periods of intense sun burn
short intermittent severe exposure especially sun burning
Describe a benign naevus
- Symmetrical
- Even borders
- Uniform colour
- Diameter of less than 6mm
Describe a malignant melanoma mole
- Asymmetrical
- Borders uneven
- Colour variation
- Diameter greater than 6mm
- Lesion has changed recently
Name the most common type of melanoma in Britain
Superficial spreading melanoma
Describe early superficial spreading melanoma lesions
Flat macule
Describe late superficial spreading melanoma lesions
Blue / black nodules
Describe how superficial spreading melanomas look macroscopically
Proliferation of atypical melanocytes which invade epidermis and dermis
Describe the genetics of superficial spreading melanomas
Often BRAF mutations occur
How do we treat superficial spreading melanomas
By using anticancer agents
Name some different subtypes of melanomas
- Superficial spreading melanomas
- Nodular melanoma
- Lentigo maligna
What is the difference between a superficial melanoma and a nodular melanoma
In nodular melanomas microscopically you don’t see extensions of the tumour within the dermis
Describe nodular melanomas
They start as a pigmented nodule that can ulcerate
What is the prognosis like for nodular melanomas
Poor prognosis
Describe how nodular melanomas look microscopically
Invasive atypical melanocytes invade the dermis to produce nodules of tumour cells
Who are more likely to see lentigo malinga on?
Seen on chronically sun exposed sites in ELDERLY patients
eg face
Describe lentigo malinga lesions
They tend to be very big flat pigmented areas of the skin
They grow via disk adhesive single cells along the dermo epidermis junction
Why are lentigo malinga tumours hard to get rid of?
They usually form at difficult to operate sites
They are ill defined
How do we treat lentigo malinga lesions
We can use local therapies such as creams
As lentigo malinga lesions progress what happens
Melanocytes may invade the dermis (forming a lentigo malignant melanoma)
This has the potential to metastasise)
What are the problems associated with lentigo malinga melanomas
They have the potential to metastasise
Which mutations are common in lentigo malingas
KIT mutations are more common
Which mutations don’t usually occur in lentigo malingas and what problems does this cause
BRAF mutations are less common
This means the Vemurafenib drug tends not to work
Name 2 subtype of lentigo melanomas
- Acral lentiginous melanoma
- Mucosal melanomas
Where are Acral lentiginous melanomas formed
On the palms and soles (occasionally sublingual)
In whom are Acral lentiginous melanoma common
Afro carribeans
How do Acral lentiginous melanoma look like
They form enlarging pigmented patches
What type of mutations do Acral lentiginous melanoma exhibit
KIT mutations
How common are mucosal melanomas
Rare and they often have a poor prognosis
Where do mucosal melanomas usually form?
Oral cavity
Nasal cavity
Genitourinary
GI tract
Describe how mucosal melanomas present clinically
Clinically may be a pigmented patch
Describe how mucosal melanomas look under a microscope
They have an early lentiginous growth pattern
What causes mucosal membranes
KIT mutation
GNAQ mutation
How do we determine the prognosis of a tumour
- Breslow thickness
- Site of tumour
- If the tumour ulcerates
- Satellites/ in transit
- If lymph nodes are affected
What is breslows thickness
It is a measure through a microscope from the granular later of the epidermis to the base of the tumour
According to breslows thickness if a tumours is less than 1mm what is the 5 year survival percentage of a patient
91-95%
According to breslows thickness if a tumours is between 1-2mm what is the 5 year survival percentage of a patient
75-90%
According to breslows thickness if a tumours is between 2-4mm what is the 5 year survival percentage of a patient
60-75%
According to breslows thickness if a tumours is greater than 4 what is the 5 year survival percentage of a patient
45-60%
A melanoma on which sites in the body have a poor prognosis
Back
Arms
Neck
Scalp
If a tumour ulcerates does that mean it have a poorer or Better prognosis?
If the tumour has ulcerated it has a POORER prognosis
What do advanced melanomas sometimes form?
Satellites/ transits
What are satellites in terms of tumours
They are cutaneous deposits that occur before lymph nodes are affected
In patients with thick or ulcerated tumours what do we usually take
A sentinel node biopsy
What is the significance of the sentinel node?
It is the lymph node which drain from melanomas first so if we remove it and it tests positive it indicates that most lilt the rest of the lymph nodes in that anatomic areas are affected
If a sentinel node biopsy come back positive what should we do?
Remove all the lymph nodes in that autonomic areas to try and halt disease progression
What are the problems associated with removing all the lymph nodes from a certain area?
Can lead to lymphedema which ultimately harms the patent
How can we treat melanomas?
- Surgery
- BRAF inhibitors
- Immunotherapy
How many melanomas are caused by the BRAF gene?
60%
What is immunotherapy
Drugs which prevent tumour cells from deactivating T cells which may kill them