Superficial spreading melanoma

Superficial spreading melanoma
Other names: Superficially spreading melanoma[1]
SpecialtyDermatology

Superficial spreading melanoma (SSM) is usually characterized as the most common form of cutaneous melanoma[2] in Caucasians. The average age at diagnosis is in the fifth decade, and it tends to occur on sun-exposed skin, especially on the backs of males and lower limbs of females.

Signs and symptoms

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.

  • Superficial spreading melanoma, Breslow 0.7mm, arising within a melanoma in situ, nonpolarised dermoscopy view
  • Superficial spreading melanoma, Breslow 0.25 mm, polarised dermoscopy view
  • Superficial spreading melanoma, Breslow 0.5 mm, nonpolarised dermoscopy view
  • Superficial spreading melanoma, Breslow 0.4 mm, nonpolarised dermoscopy view

Histopathology

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

Treatment is by excisional biopsy, wide local excision and possibly sentinel node biopsy. Spread of disease to local lymph nodes or distant sites (typically brain, bone, skin and lung) marks a decidedly poor prognosis.

See also

References

  1. ↑ James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0.
  2. ↑ Forman SB, Ferringer TC, Peckham SJ, et al. (June 2008). "Is superficial spreading melanoma still the most common form of malignant melanoma?". J. Am. Acad. Dermatol. 58 (6): 1013–20. doi:10.1016/j.jaad.2007.10.650. PMID 18485983.
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