- Email: [email protected]
Benign skin tumours
SKIN TUMOURS
Benign skin tumours Julia Schofield
10 Bowen’s disease on the lower leg. A well-demarcated, erythematous, scaly plaque.
Benign skin tumours are common and can arise from any part of the skin (Figure 1). Patients often present to the doctor seeking reassurance about what their skin lesion is, its natural history and whether it needs to be removed. This contribution describes the most common benign skin tumours and aims to provide information to answer these questions. Making a correct clinical diagnosis is important to ensure that the lesion is managed appropriately.
Melanocytic naevi (‘moles’) Clinical features – melanocytic naevi are the most common benign skin lesions. They are usually termed ‘moles’ and present with a variety of clinical appearances. They generally start to appear in puberty and early adult life, and it is not uncommon for individuals to have 30−40 naevi, usually on light-exposed skin. A melanocytic naevus often evolves through three stages, from a flat, dark, evenly pigmented junctional naevus to a raised, pigmented compound naevus to a mature intradermal naevus. The latter is flesh-coloured because there is no longer junctional melanocytic activity at the dermo-epidermal junction; instead, the melanocytes
11 Actinic keratosis on the pinna (a common site) caused by chronic sun exposure.
larger, progressive or symptomatic lesions; such changes may suggest early malignant transformation. Topical therapy or superficial destructive modalities are the treatments of choice. Actinic keratoses can resolve spontaneously if the involved area is protected from ultraviolet radiation.
Derivation of benign skin tumours
Prevention of skin cancer
Part of skin • Melanocytes
The most important aetiological factor in the development of both melanoma and non-melanoma skin cancer is exposure to natural and artificial ultraviolet light. Most public health programmes are aimed at young people and stress the importance of avoiding sunbathing and sun-beds, and using sensible sun-protection measures to reduce the risk of skin cancer in later life.
• Epidermal keratinocytes • Hair follicles • Fibroblasts in dermis • Blood vessels
REFERENCES 1 Lens M B, Dawes M. Global perspectives of contemporary epidemiological trends of cutaneous malignant melanoma. Br J Dermatol 2004; 150: 179–85. 2 Cancer Research UK. www.cancerresearchuk.org 3 Bath-Hextall F, Bong J, Perkins W et al. Interventions for basal cell carcinoma of the skin: systematic review. BMJJ 2004; 329: 705.
Spider naevi, Campbell de Morgan spots, pyogenic granuloma
1
Julia Schofield d is Consultant Dermatologist at St Albans and Hemel Hempstead Hospitals, West Hertfordshire NHS Hospitals Trust, UK. She qualified in Manchester, and trained in general practice and dermatology in Salford, Watford and London. Her interests include teaching minor surgical skills to general practitioners and nurses. She is currently Clinical Lead for Dermatology for the NHS Modernisation Agency.
FURTHER READING Colver G, ed. Skin cancer: a practical guide to management. London: Martin Dunitz, 2002. Schwartz R A. Skin cancer. Dermatol Surg 2004; 30: 243–350.
MEDICINE 33:1
Benign skin tumour Junctional melanocytic naevus, compound melanocytic naevus, intradermal melanocytic naevus, halo naevus, atypical melanocytic naevus Basal cell papilloma (seborrhoeic keratosis), solar keratosis Epidermoid cyst (also termed ‘pilar cyst’) Dermatofibroma
67
© 2005 The Medicine Publishing Company Ltd
SKIN TUMOURS
are deep in the dermis. Some melanocytic naevi in young adults develop a depigmented halo, followed by involution of the naevus and repigmentation of the halo. This is termed a ‘halo naevus’ and is no cause for concern. Atypical melanocytic naevi are so-called because of their irregular outline and variable pigmentation. They are usually larger than other benign naevi, measuring more than 5 mm in diameter. It can be difficult to distinguish an atypical melanocytic naevus (Figure 2) from a malignant melanoma. Patients with large numbers of atypical melanocytic naevi may have atypical mole syndrome, which is associated with an increased risk of malignant melanoma. Managementt – most benign melanocytic naevi do not require excision unless there is concern about a possible diagnosis of malignant melanoma (see page 64). When such lesions are excised, ellipse excision with a 2 mm margin is recommended. When the clinical diagnosis is confident, compound naevi can be removed by shave excision. Specimens must always be sent for histopathological examination.
Seborrhoeic keratosis (basal cell papilloma). This pigmented, superficial, crusty lesion looks as if it could be lifted off the skin surface. The typical blocked follicular orifices, best seen with a hand lens, are a useful diagnostic clue. Epidermal proliferation
Seborrhoeic keratosis (basal cell papilloma) The terminology of these lesions is confused. ‘Seborrhoeic keratosis’ describes the clinical appearance and ‘basal cell papilloma’ the histological appearance. Both terms are acceptable and can be used synonymously. Clinical features – these lesions are very common, usually pigmented, and start to appear in the fifth decade of life in both men and women. They do not resolve spontaneously. Multiple lesions often develop in predisposed individuals. Some elderly patients have large areas of affected skin. The lesions are most common on the trunk and face, and vary in size between a few millimetres and 2−3 cm. Typical seborrhoeic keratoses resemble greasy, crusty plaques that are adherent to the skin surface but look as though they could easily be lifted off (Figure 3). The crust often drops off, but subsequently reforms. Many are itchy, and some become irritated and inflamed when scratched. The presence of plugged follicular orifices seen on the surface with a hand lens is a useful diagnostic clue. It is said that malignant change never occurs in these lesions. Seborrhoeic keratoses are often confused with benign melanocytic naevi and malignant melanoma. Managementt – when the diagnosis is certain, explanation and reassurance are often all that is required. Patients must be
3
warned that new lesions may develop. Curettage and cautery or liquid nitrogen cryotherapy can be used to remove symptomatic or disfiguring lesions that are causing distress. Curettings should be sent for histological examination. Cryotherapy should be used only when the clinical diagnosis is confident, because histological confirmation will not be possible.
Epidermoid cyst Epidermoid cysts are often incorrectly termed ‘sebaceous cysts’. True sebaceous cysts are very rare. Clinical features – epidermoid cysts are common on the scalp, neck, chest and back, particularly in young adults. They comprise an epidermoid wall surrounding a core containing keratin and its breakdown products (Figure 4). The latter have a characteristic cheesy appearance and foul odour. The cyst is situated in the dermis; the overlying skin is usually normal. Often, a keratin-filled punctum marks the point of attachment to the skin. Epidermoid cysts are usually asymptomatic, but can become inflamed and infected. Managementt – non-inflamed cysts can be excised surgically under local anaesthetic. Inflamed cysts should be treated by excision and drainage initially, and removed electively when any infection and inflammatory response have resolved.
Dermatofibroma (histiocytoma) Clinical features – dermatofibromas are common, particularly on the lower limbs of women. They are thought to be an abnormal response to an insect bite, representing a proliferation of fibroblasts within the dermis. They present as a persistent, firm, hard nodule
2 Atypical melanocytic naevi. Note the irregular outline and variable pigmentation. These lesions can sometimes be difficult to distinguish from malignant melanoma.
MEDICINE 33:1
68
© 2005 The Medicine Publishing Company Ltd
SKIN TUMOURS
Epidermoid cyst of the scalp with a typical domed appearance. The overlying epidermis is normal. On sites such as the back, where there is more subcutaneous tissue, the lesion is less likely to be raised above the surrounding skin.
Pyogenic granuloma. This shows the typical clinical features of a juicy, red nodule. These lesions are usually rapidly enlarging and bleed profusely when knocked.
Punctum Blood vessels Keratin-filled cyst
Collar of epidermis
Pilosebaceous unit
6
4
that is often itchy (Figure 5). The appearance can vary depending on the overlying epidermis, which is sometimes pigmented. Managementt – there is no medical indication for excision of a dermatofibroma when the clinical diagnosis is not in doubt. When excision is requested for cosmetic reasons, the lesion can be removed by ellipse excision. However, the resulting scar may look worse than the nodule, and this should be considered carefully.
Pyogenic granuloma Clinical features – pyogenic granulomata occur equally in both sexes, and at any age, including in childhood. They represent an abnormal proliferation of blood vessels and are typically rapidly enlarging, bright red, juicy lesions that bleed easily and profusely (Figure 6). They are most commonly seen on the extremities, and there is sometimes a history of a minor penetrating injury a few weeks before the development of the lesion. Managementt – these lesions are ideally suited to curettage and cautery, but often bleed profusely during the procedure. The differential diagnosis of pyogenic granuloma includes amelanotic melanoma, so urgent removal and careful review of the histopathology report is important. FURTHER READING Brown J S. Minor surgery: a text and atlas. 2nd ed. London: Chapman & Hall, 1992. Champion R H, Burton J L, Burns D A et al., eds. Textbook of dermatology. 6th ed. Oxford: Blackwell Science, 1998. Marks R. Roxburgh’s common skin diseases. 16th ed. London: Chapman & Hall, 1993. (Basic dermatological textbook with a good chapter on benign skin lesions and high-quality illustrations.)
5 Dermatofibroma (histiocytoma). This is a persistent, firm nodule. The overlying epidermis is usually pink, but can be pigmented.
MEDICINE 33:1
69
© 2005 The Medicine Publishing Company Ltd
Benign skin tumours Julia Schofield
10 Bowen’s disease on the lower leg. A well-demarcated, erythematous, scaly plaque.
Benign skin tumours are common and can arise from any part of the skin (Figure 1). Patients often present to the doctor seeking reassurance about what their skin lesion is, its natural history and whether it needs to be removed. This contribution describes the most common benign skin tumours and aims to provide information to answer these questions. Making a correct clinical diagnosis is important to ensure that the lesion is managed appropriately.
Melanocytic naevi (‘moles’) Clinical features – melanocytic naevi are the most common benign skin lesions. They are usually termed ‘moles’ and present with a variety of clinical appearances. They generally start to appear in puberty and early adult life, and it is not uncommon for individuals to have 30−40 naevi, usually on light-exposed skin. A melanocytic naevus often evolves through three stages, from a flat, dark, evenly pigmented junctional naevus to a raised, pigmented compound naevus to a mature intradermal naevus. The latter is flesh-coloured because there is no longer junctional melanocytic activity at the dermo-epidermal junction; instead, the melanocytes
11 Actinic keratosis on the pinna (a common site) caused by chronic sun exposure.
larger, progressive or symptomatic lesions; such changes may suggest early malignant transformation. Topical therapy or superficial destructive modalities are the treatments of choice. Actinic keratoses can resolve spontaneously if the involved area is protected from ultraviolet radiation.
Derivation of benign skin tumours
Prevention of skin cancer
Part of skin • Melanocytes
The most important aetiological factor in the development of both melanoma and non-melanoma skin cancer is exposure to natural and artificial ultraviolet light. Most public health programmes are aimed at young people and stress the importance of avoiding sunbathing and sun-beds, and using sensible sun-protection measures to reduce the risk of skin cancer in later life.
• Epidermal keratinocytes • Hair follicles • Fibroblasts in dermis • Blood vessels
REFERENCES 1 Lens M B, Dawes M. Global perspectives of contemporary epidemiological trends of cutaneous malignant melanoma. Br J Dermatol 2004; 150: 179–85. 2 Cancer Research UK. www.cancerresearchuk.org 3 Bath-Hextall F, Bong J, Perkins W et al. Interventions for basal cell carcinoma of the skin: systematic review. BMJJ 2004; 329: 705.
Spider naevi, Campbell de Morgan spots, pyogenic granuloma
1
Julia Schofield d is Consultant Dermatologist at St Albans and Hemel Hempstead Hospitals, West Hertfordshire NHS Hospitals Trust, UK. She qualified in Manchester, and trained in general practice and dermatology in Salford, Watford and London. Her interests include teaching minor surgical skills to general practitioners and nurses. She is currently Clinical Lead for Dermatology for the NHS Modernisation Agency.
FURTHER READING Colver G, ed. Skin cancer: a practical guide to management. London: Martin Dunitz, 2002. Schwartz R A. Skin cancer. Dermatol Surg 2004; 30: 243–350.
MEDICINE 33:1
Benign skin tumour Junctional melanocytic naevus, compound melanocytic naevus, intradermal melanocytic naevus, halo naevus, atypical melanocytic naevus Basal cell papilloma (seborrhoeic keratosis), solar keratosis Epidermoid cyst (also termed ‘pilar cyst’) Dermatofibroma
67
© 2005 The Medicine Publishing Company Ltd
SKIN TUMOURS
are deep in the dermis. Some melanocytic naevi in young adults develop a depigmented halo, followed by involution of the naevus and repigmentation of the halo. This is termed a ‘halo naevus’ and is no cause for concern. Atypical melanocytic naevi are so-called because of their irregular outline and variable pigmentation. They are usually larger than other benign naevi, measuring more than 5 mm in diameter. It can be difficult to distinguish an atypical melanocytic naevus (Figure 2) from a malignant melanoma. Patients with large numbers of atypical melanocytic naevi may have atypical mole syndrome, which is associated with an increased risk of malignant melanoma. Managementt – most benign melanocytic naevi do not require excision unless there is concern about a possible diagnosis of malignant melanoma (see page 64). When such lesions are excised, ellipse excision with a 2 mm margin is recommended. When the clinical diagnosis is confident, compound naevi can be removed by shave excision. Specimens must always be sent for histopathological examination.
Seborrhoeic keratosis (basal cell papilloma). This pigmented, superficial, crusty lesion looks as if it could be lifted off the skin surface. The typical blocked follicular orifices, best seen with a hand lens, are a useful diagnostic clue. Epidermal proliferation
Seborrhoeic keratosis (basal cell papilloma) The terminology of these lesions is confused. ‘Seborrhoeic keratosis’ describes the clinical appearance and ‘basal cell papilloma’ the histological appearance. Both terms are acceptable and can be used synonymously. Clinical features – these lesions are very common, usually pigmented, and start to appear in the fifth decade of life in both men and women. They do not resolve spontaneously. Multiple lesions often develop in predisposed individuals. Some elderly patients have large areas of affected skin. The lesions are most common on the trunk and face, and vary in size between a few millimetres and 2−3 cm. Typical seborrhoeic keratoses resemble greasy, crusty plaques that are adherent to the skin surface but look as though they could easily be lifted off (Figure 3). The crust often drops off, but subsequently reforms. Many are itchy, and some become irritated and inflamed when scratched. The presence of plugged follicular orifices seen on the surface with a hand lens is a useful diagnostic clue. It is said that malignant change never occurs in these lesions. Seborrhoeic keratoses are often confused with benign melanocytic naevi and malignant melanoma. Managementt – when the diagnosis is certain, explanation and reassurance are often all that is required. Patients must be
3
warned that new lesions may develop. Curettage and cautery or liquid nitrogen cryotherapy can be used to remove symptomatic or disfiguring lesions that are causing distress. Curettings should be sent for histological examination. Cryotherapy should be used only when the clinical diagnosis is confident, because histological confirmation will not be possible.
Epidermoid cyst Epidermoid cysts are often incorrectly termed ‘sebaceous cysts’. True sebaceous cysts are very rare. Clinical features – epidermoid cysts are common on the scalp, neck, chest and back, particularly in young adults. They comprise an epidermoid wall surrounding a core containing keratin and its breakdown products (Figure 4). The latter have a characteristic cheesy appearance and foul odour. The cyst is situated in the dermis; the overlying skin is usually normal. Often, a keratin-filled punctum marks the point of attachment to the skin. Epidermoid cysts are usually asymptomatic, but can become inflamed and infected. Managementt – non-inflamed cysts can be excised surgically under local anaesthetic. Inflamed cysts should be treated by excision and drainage initially, and removed electively when any infection and inflammatory response have resolved.
Dermatofibroma (histiocytoma) Clinical features – dermatofibromas are common, particularly on the lower limbs of women. They are thought to be an abnormal response to an insect bite, representing a proliferation of fibroblasts within the dermis. They present as a persistent, firm, hard nodule
2 Atypical melanocytic naevi. Note the irregular outline and variable pigmentation. These lesions can sometimes be difficult to distinguish from malignant melanoma.
MEDICINE 33:1
68
© 2005 The Medicine Publishing Company Ltd
SKIN TUMOURS
Epidermoid cyst of the scalp with a typical domed appearance. The overlying epidermis is normal. On sites such as the back, where there is more subcutaneous tissue, the lesion is less likely to be raised above the surrounding skin.
Pyogenic granuloma. This shows the typical clinical features of a juicy, red nodule. These lesions are usually rapidly enlarging and bleed profusely when knocked.
Punctum Blood vessels Keratin-filled cyst
Collar of epidermis
Pilosebaceous unit
6
4
that is often itchy (Figure 5). The appearance can vary depending on the overlying epidermis, which is sometimes pigmented. Managementt – there is no medical indication for excision of a dermatofibroma when the clinical diagnosis is not in doubt. When excision is requested for cosmetic reasons, the lesion can be removed by ellipse excision. However, the resulting scar may look worse than the nodule, and this should be considered carefully.
Pyogenic granuloma Clinical features – pyogenic granulomata occur equally in both sexes, and at any age, including in childhood. They represent an abnormal proliferation of blood vessels and are typically rapidly enlarging, bright red, juicy lesions that bleed easily and profusely (Figure 6). They are most commonly seen on the extremities, and there is sometimes a history of a minor penetrating injury a few weeks before the development of the lesion. Managementt – these lesions are ideally suited to curettage and cautery, but often bleed profusely during the procedure. The differential diagnosis of pyogenic granuloma includes amelanotic melanoma, so urgent removal and careful review of the histopathology report is important. FURTHER READING Brown J S. Minor surgery: a text and atlas. 2nd ed. London: Chapman & Hall, 1992. Champion R H, Burton J L, Burns D A et al., eds. Textbook of dermatology. 6th ed. Oxford: Blackwell Science, 1998. Marks R. Roxburgh’s common skin diseases. 16th ed. London: Chapman & Hall, 1993. (Basic dermatological textbook with a good chapter on benign skin lesions and high-quality illustrations.)
5 Dermatofibroma (histiocytoma). This is a persistent, firm nodule. The overlying epidermis is usually pink, but can be pigmented.
MEDICINE 33:1
69
© 2005 The Medicine Publishing Company Ltd