Basal Cell Carcinoma


INTRODUCTION

Slow growing skin cancer that is locally invasive and rarely metastasizes

top D I A B M I M home


EPIDEMIOLOGY

Incidence
The commonest cancer.
1/600/yr.
Age

Incidence increases with age / cumulative sun exposure.
Race
Fair skinned, blue-eyed, red-haird, Celtic origins.
Rare in dark-skinned races.
Sex
M>F; occupational.

Risk Factors
Environmental
Occur almost exclusively in sun-exposed skin.
top D I A B M I M home


AETIOLOGY

Very commonly

Sun exposure (UVB).

Very rarely

Naevoid BCC syndrome (Gorlin's Syndrome)
- presence of multiple BCC's in a young adult with palmar pits, bifid ribs, dental anomalies and jaw cysts.
Arsenic BCC
- on skin exposed to arsenic (once common in skin lotions).
Long-term X-Ray exposure
- ionising radiation
top D I A B M I M home


BIOLOGICAL BEHAVIOUR

Pathology

Thought originally to arise from the basal cell in epidermis.
Probably really from pulripotential cells of epidermis / pilosebaceous tissue.
Associated genetic abnormalities include tumour suppressor gene mutations: PTCH1 and p53
And oncogene mutations: Ras and c-fFos

Natural History
In contrast to SCC there are no precursor lesions to these.
Slow-growing.
May be multifocal.
Almost never metastasise, but cause local invasion and penetrate deeper tissue.
- metastasis associated with advanced age and neglected large lesions (>10cm2)
- often have had multiple previous past excisions.
But local recurrence may be seen.

Complications
Recurrence
Associated with:
- tumor size (>2cm face; >1cm head/neck; >0.6cm other)
- depth of invasion
- perineural invasion
- immune status of pt
- borders poorly defined
- earlier recurrence
- pst radioRx / inflammation
- rapid growth
- mod-poor differentiation.


top D I A B M I M home


MANIFESTATIONS

Symptoms
Local
Usually nodule or ulcer that fails to heal.
May be itchy.
If neglected can ulcerate deeply causing pain, bleeding and infection.
Commonly grow in a 'Bandit's Mask' distribution on the face - 85% occur in head and neck, remainder on limbs, few on trunk.



Metastatic
Local nodes should not be enlarged.
Rare but possible.

Signs / Classification
26 histological varieties described
- but only a few correlate to clinically recognisable growth patterns:

1.
Nodular (50-54%)
- well defined elevated waxy lesions.
- often quite small at presentation
- develops 'pearly opalescent' nodules at margins
- a fine network of vessels ('telangiectasia') traversing the margins (related to angiogenesis from tumour).

- classically have a central depression with 'umbilication'
- overlying epithelium is often flesh-coloured:

- some  spread laterally, leaves a central scar, with raised edges


2. Ulcerated

As lesions progress, regression may lead to an ulcer, possibly growing deeply.
- when first ulcerating, edges are rolled (centre dies).
- base is crusted with serum and bleeds if picked.
- later it becomes irregular.

- can grow deep and destructively (AKA rodent ulcer):


3. Superficial
- scaly red macular patch (10-20%)
- least aggressive form
- can extend over the skin in a multicentric pattern

- where multiple small dots pepper the skin, a more aggressive disease is active.

4. Cystic - 4-8%
- distinctive translucence
- may appear bluie or gray.


5. Pigmented - 6%
- coloured brown by excess melanin.


6. Sclerosing (morpheic)
- hard, scaly (2%).
- may be mistaken for psoriasis
- scar-like with subtle edges


7. Basosquamous
Appears likan SCC
- more likely to metastasize and treated like an SCC.

Palpate
Early lesions freely mobile.
Fixation indicates advanced lesion.
top D I A B M I M home


INVESTIGATIONS

Pathology
Histology confirmative.
Important to have excluded more serious lesions.

Staging
Same for BCC and SCC:
Stage 0
Tis
N0
M0
Stage I
T1
N0
M0
Stage II
T2 or T3
N0
M0
Stage III
T4
Any T
N0
N1
M0
M0
Stage IV
Any T
Any N
M1
T-stage
Tx = unassessable
Tis = in-site
T1 = ≤2cm (any dimension)
T2 = >2cm but not >5cm
T3 = >5cm
T4 = invasive deep to dermis (cartilage, bone. muscle etc)
N-stage
Nx = unassessable
N0 = nil
N1 = nodes.
M-stage
Mx = unassessable
M0 = nil
M1 = nodes.

top D I A B M I M home


MANAGEMENT

Prevention
Limit UV exposure.

Treatment options
Surgical vs 'Field Treatment'
Field treatments work on a generalised area, but don't define margins
Consider carefully in terms of lesion, patient and risk factors for recurrence
Surgical excision preferable for most.

Surgical

Surgical excision

Cure rate 85-95%.
Most can be safely excised to 4-5mm margins

Margins
Low risk: 4-5mm
- trunk and limbs <2cm
- head and neck <1cm
- around eyes, ears, nose, mouth, hands, feet <6mm
High risk: 10mm
- bigger than the above
- recurrent tumours
- immunocompromised
- in radiotherapy field
- morpheaform, sclerosing, micronodular types
- perineural invasion
If histology demonstrates tumour at  excision margins (<1mm from edge) 50% will recur.

Moh's micrographic surgery
High-risk alternative
99.5% cure rate
Serial transverse slices under frozen section until clearly free of tumour.
- ideal under high-risk conditions of recurrence, or for anatomic areas where preservation of tissue important (eye, nose, mouth, ear).
RCT favours use of Moh's (just) in terms of local recurrence and control
But is slow; takes 2-4h

Field Treatments

Cryotherapy, electrodesiccation, 5FU
Usually for small lesions (2-5mm)
Local control >90% for cryotherapy.
- heal slowly and leave a pale scar.

Radiotherapy
Highly effective for BCC and SCC
- also useful for difficult areas / skin at high risk of recurrence.
Generally reserved for elderly pts unsuitable for surgery / certain anatomical sites.

FAQs
Do I need to conduct routine follow-up
No, unless they have Gorlin's syndrome.

top D I A B M I M home


References
Browse 4th.

BCC

Commonest malignant skin tumour in caucasians

Rare in oriental, non existent in dark skinned

Middle age elderly

Aetiology

Risk factors

Sun exposure

XRT

Arsenic ingestion

Trauma

Rare

Immunosuppression

Basal Cell Naevus syndrome (Gorlin syndrome)

Autosomal dominant

Multiple BCC

Begins in childhood

Asscoiciated with odontogenic cycts in mandible & medulloblastoma

? cell of origin

epidermal basal cell

epithelium of hair follicles

Pathology

Macro

Raised nodule

Waxy appearance

Tiny vessels

Umbilication

rolled (not everted), pearly edges

Micro

Islands of uniform darkly staining cells similar to basal cells. There are no prickle cells or epithelial         pearls

Nuclei line up in regular fashion @ periphery palisading

Fibrous stromal reaction

Variants

Cystic (Nodular)

Central degeneration of cells

Pigmented

Within macrophages in stroma

Multifocal

Diffuse scaly erythematous patch sometimes confused with eczema

Multiple widely dispersed buds of tumour along dermal-epidermal junction

Sclerosing (Morpheaform)

Sparsely infiltrating strands infiltrating deeply

Dense fibrous stroma

Metatypical

(basisquamous)

Aggressive behaviour

Little palisading

Spread

Local invasion of bone or cartilag

Late

LNM very rare

0.4%

Basisquamous most likely

Rx

Excision Surgical excision is preferred local treatment for majority of BCC and SCC

    Clear margins should be achieved with 3-5mm margin of normal tissue.

    Mohs micrographic excision

o   Mohs may reduce recurrence rate when there are risk factors for subclinical invasion and recurrence and it is imperative to preserve as much tissue as possible

  Recurrent tumour

  Tumour is on the hand/foot, genitals, in front or behind ear, temple, mandible or chin, lip, nose, peri-orbital region or central face and >6mm

  Cheek, forehead, scalp or neck and >10mm

  Trunk or extremity and >20mm

  Morpheaform, fibrosing, sclerosing or infiltrating

  Ill-defined clinical borders

  Perineural invasion

  Associated with prior radiotherapy

  immunosuppression

Absolute indication if recurrence of previosly irradiated tumour

XRT

As above

Cryotherapy

As above

5FU cream

Prognosis

36% will develop a 2nd 1 BCC within the next 5 years.

Local recurrence

More likely:

Infiltrating

Multifocal

Sclerosing

Margins

30% with +ve margins recur

Size

T 1.5 cm 12% 5 years

T > 3.0 cm23%5 years

Site

H&N 1 13% to 25% 5yrs