Basal Cell Carcinoma (BCC)

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Basal cell carcinoma (BCC)\: most common cancer globally, non-melanoma skin cancer, slow-growing, rarely metastasises.
Incidence\: higher in low latitude areas (e.g., Australia), fair-skinned individuals; rising due to ageing population and UV
exposure.
Aetiology\: develops from mutations in PTCH and TP53 genes, a
Risk factors\: UV radiation exposure (especially in youth), fair skin, ionising radiation, repeated micro-injuries, scars, chemical
agents, Gorlin syndrome, immunosuppression, history of skin cancer.
Clinical features\: typically in sun-exposed areas; usually asymptomatic, slow-growing, local invasion common.
Types\: Nodular (pearly papules/nodules, common on head), Super
Morpheaform (poorly de
Management\: high recurrence-free rates with early treatment; options include surgical removal, ED&C, 5-FU, cryotherapy,
photodynamic therapy, Mohs surgery for high-risk cases.
Complications\: recurrence, risk of other skin cancers, dis
nerves, muscles in aggressive cases.
Specialist referral\: recommended for challenging diagnoses to con
carcinoma and melanoma.
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Introduction

Basal cell carcinoma (BCC) is the most common type of cancer in the world. 1
that develops very slowly in the upper layers of the skin and rarely metastasises.
It is a non-melanoma form of skin cancer
The incidence of BCC is higher in areas with low geographic latitude (with Australia being the country with the highest
incidence of the disease) and people with low pigment status.
2
Recently, a rapid increase in the incidence of BCC has been noted in Western countries, most likely attributed to the ageing
population and arti
3

Aetiology

The skin consists of three layers\:
4,5
The epidermis\: the thin outer portion of the skin made up of the inner basal layer, the prickle cell layer, the granule cell
layer and the keratinised squamous layer (Figure 1)
The dermis\: the thicker inner portion of the skin which consists of connective tissue and contains nerves, vessels and
sweat glands
The hypodermis\: the innermost layer that fuses with the dermis and consists of adipose tissue and sweat glandsFigure 1. The layers of the epidermis
BCCs develop from mutations, usually in the PTCH and TP53 genes, a

Risk factors

Risk factors for the development of BCC include\:
6,7,8,9
Exposure to UV radiation, especially acute intermittent exposure at a young age
Fair skin prone to sunburn that does not tan easily
Ionising radiation
Repeated micro-injuries
Scars/chronic ulcers
Prolonged exposure to chemical agents (i.e. arsenic)
Gorlin syndrome
Immunosuppression
History of skin cancer

Clinical features

Most BCCs occur in sun-exposed areas, commonly on the face. BCCs develop very slowly and rarely metastasise. Local
invasion is the most common mechanism of spread. They are usually asymptomatic but can present with pruritus or mild
discomfort.
Clinically, BCCs can be categorised into three main types\: nodular, super
Nodular BCC
Nodular BCC is the most common type and usually presents on the head (eyelids, cheeks, forehead). Nodular BCCs
clinically appear as pearly, shiny papules or nodules with small arborising telangiectasias, rolled borders and sometimes a
depressed centre. Lesions are very sensitive and may bleed on minor trauma.
10
Figure 2. Nodular BCC
Super
Super
pink skin. Some super
and in younger patients.
10,11Figure 3. Super
Morpheaform BCC
Also referred to as sclerosing or in
poorly de
prognosis since it can subclinically destroy surrounding tissue.
10
Figure 4. Morphoeic basal cell carcinoma
Pigmented BCCs
Less frequently, various amounts of melanin might be present in a BCC, which is then referred to as pigmented. The
di
Figure 5. Pigmented BCC
Clinical examination
A thorough clinical examination is required to identify characteristic BCC features and aid diagnosis. For more information,
see the Geeky Medics guides to examining a non-pigmented skin lesion and pigmented skin lesion.
Dermatoscopy involves examining skin lesions with a dermatoscope, a magnifying tool that utilises polarised light. With
dermatoscopy, diagnostic features of a BCC not visible to the naked eye (e.g. telangiectasias, microulcerations or globules)
are easily identi
11

Di

Di
Nodular\: molluscum contagiosum, amelanotic melanoma,
Superpsoriasis, lichenoid keratosis, actinic keratosis, Bowen’s disease
Morpheaform\: scar, localised scleroderma (morphea), Merkel cell carcinoma, amelanotic melanoma

Investigations

The de
13
Nodular and super
spread and high recurrence rate.
Common histologic features of all BCCs include\:
14
Basophilic aggregations of basaloid keratinocytes with large nuclei and scant cytoplasm
Clefts of tumour tissue
Peripheral palisading of nuclei
Apoptotic cells
Figure 6. Histology of BCC. Basaloid
aggregates emanating from the
epidermis and growing along an axis
parallel to the epidermis. Peripheral
palisading and clefting are present.

Management

Recurrence-free treatment rates of BCC are high, up to 95%, with early diagnosis and management. The main goal of
treatment is the complete removal of the tumour with preservation of the function and cosmesis of the a
type of treatment depends on whether the BCC is low or high risk.
15
Low-risk BCCs are usually treated with complete surgical removal or electrodesiccation and curettage (ED&C). Other
treatment options for low-risk BCC include topical 5-
Mohs micrographic surgery is a specialist removal method for non-melanoma skin cancers with high recurrence risk. It
has the advantage of preserving as much surrounding skin as possible. As an alternative for high-risk lesions, simple
resection with adjunct radiotherapy has been recommended.
16,17,18
The clinical diagnosis of BCC is sometimes challenging. In this case, a referral to a specialist dermatologist or oculoplastic
ophthalmologist is recommended to consquamous cell
carcinomas and melanomas, which might imitate BCCs, are appropriately detected and treated.

Complications

Complications of basal cell carcinomas include\:
19
Recurrence
Increased risk of developing other types of skin cancer, including melanoma
Dis
Aggressive forms of skin cancer can invade and destroy bones, nerves and muscles
Metastasis in rare cases

References

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Carcinomas) in the US Population, 2012. JAMA Dermatol. 2015;151\:1081.Verkouteren J.A.C., Ramdas K.H.R., Wakkee M., Nijsten T. Epidemiology of basal cell carcinoma\: Scholarly review. Br. J.
Dermatol. 2017;177\:359–372.
Teng Y, Yu Y, Li S, Huang Y, Xu D, Tao X, Fan Y. Ultraviolet Radiation and Basal Cell Carcinoma\: An Environmental
Perspective. Front Public Health. 2021 Jul 22;9\:666528.
Marghoob AA. Skin cancers and their etiologies. Semin Cutan Med Surg. 2011 Dec;30(4 Suppl)\:S1-5.
Marzuka AG, Book SE. Basal cell carcinoma\: pathogenesis, epidemiology, clinical features, diagnosis, histopathology, and
management. Yale J Biol Med. 2015 Jun 1;88(2)\:167-79.
Karagas MR, McDonald JA, Greenberg ER, Stukel TA, Weiss JE, Baron JA. et al. Risk of basal cell and squamous cell skin
cancers after ionizing radiation therapy. For The Skin Cancer Prevention Study Group. J Natl Cancer Inst. 1996;88(24)\:1848–
1853.
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cell carcinoma. A possible indicator of di
Altamura D, Menzies SW, Argenziano G, Zalaudek I, Soyer HP, Sera F. et al. Dermatoscopy of basal cell carcinoma\:
morphologic variability of global and local features and accuracy of diagnosis. J Am Acad Dermatol. 2010;62(1)\:67–75.
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Dermatol. 2012;66(1)\:106–111.
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excision. J Dermatol Surg Oncol. 1992;18(6)\:471–476.
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Compr Canc Netw. 2010;8(8)\:836–864.
Neville JA, Welch E, Le
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Image references
Figure 1. OpenStax. L a y e r s o f t h e e p i d e r m i s . License\: [CC BY]
Figure 2. DermNet. N o d u l a r b a s a l c e l l c a r c i n o m a . License\: [CC BY-NC-ND]
Figure 3. DermNet. S u p e r CC BY-NC-ND]
Figure 4. DermNet. M o r p h o e i c b a s a l c e l l c a r c i n o m a . License\: [CC BY-NC-ND]
Figure 5. DermNet. P i g m e n t e d b a s a l c e l l c a r c i n o m a . License\: [CC BY-NC-ND]
Figure 5. DermNet. B a s a l c e l l c a r c i n o m a p a t h o l o g y . License\: [CC BY-NC-ND]

Reviewer

Anna Gkountelia
Consultant Oculoplastic Ophthalmologist

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Contents

Introduction
Aetiology
Risk factors
Source\: geekymedics.com