Superficial spreading melanoma
| Superficial spreading melanoma | |
|---|---|
| Other names | Superficially spreading melanoma[1] |
 | |
| Specialty | Dermatology |
Superficial spreading melanoma (SSM) is a type of skin cancer that typically starts as an irregularly edged dark spot typically on sun-exposed part of the body.[2][3] The colour may be variable with dark, light and reddish shades; occasionally no color at all.[2] It typically grows in diameter before spreading to deeper tissue, forming a bump or becoming an ulcer.[2] Itching, bleeding and crust formation may occur in some.[2] The backs and shoulders of males and legs of women are particularly prone.[2]
It is a type of melanocytic tumor occurring in intermittently sun-exposed skin.[2] The cause is associated with repeated sunburns in childhood, intermittent exposure to sun during life, and sun bed use.[2]
Two-thirds of cases occur in light skin, and it less common in dark skin.[2]
The average age at diagnosis is in the fifth decade.[citation needed]
Signs and symptoms
[edit]Often, this disease evolves from a precursor lesion, usually a dysplastic nevus. Otherwise it arises in previously normal skin. A prolonged radial growth phase, where the lesion remains thin, may eventually be followed by a vertical growth phase where the lesion becomes thick and nodular. As the risk of spread varies with the thickness, early SSM is more frequently cured than late nodular melanoma.
Histopathology
[edit]The microscopic hallmarks are:
- Large melanocytic cells with nest formation along the dermo-epidermal junction.
- Invasion of the upper epidermis in a pagetoid fashion (discohesive single cell growth).
- The pattern of rete ridges is often effaced.
- Invasion of the dermis by atypical, pleomorphic melanocytes
- Absence of the 'maturation' typical of naevus cells
- Mitoses
Treatment
[edit]Treatment is by excisional biopsy, wide local excision and possibly sentinel node biopsy. Localized melanoma, which has not spread beyond the skin, has a very good prognosis with low recurrence rates. Spread of disease to local lymph nodes or distant sites (typically brain, bone, skin and lung) marks a decidedly poor prognosis.
See also
[edit]References
[edit]- ^ James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0.
- ^ a b c d e f g h DE, Elder; D, Massi; RA, Scolyer; R, Willemze (2018). "2. Melanocytic tumours". WHO Classification of Skin Tumours. Vol. 11 (4th ed.). Lyon (France): World Health Organization. pp. 76–77. ISBN 978-92-832-2440-2.
- ^ "Superficial spreading melanoma | DermNet". dermnetnz.org. Retrieved 1 July 2023.