Melanoma superficial spreading C43.L

Most common form of malignant melanoma (about 60-70% of all malignant melanomas), which is characterized by primarily horizontal growth, in advanced stages of the disease also by vertical, invasive growth.

The SSM group includes about 70% of all melanomas.

Age at first diagnosis between 30 and 50 years.

Occurs in all parts of the body.

In men mainly on the trunk; in women mainly on the lower legs.

0.5 cm to 5.0 cm in size, roundish to oval, often also bizarrely configured, with tongue-shaped extensions, sharply defined, light brown to brownish, black, grey, also pink to reddish pied, initially flat plaques (no spot or patch: a spot cannot be felt with closed eyes), possibly with slightly raised edges.

Later bumpy surface, formation of infiltrated papules or nodes (vertical growth direction). Vertical growth with knot formation can start surprisingly fast within a few weeks.

Typical for the SSM are regression zones of varying size so that circinous or anular formations can develop.

Incident light microscopy: highly irregular, wide-meshed, coarse trabecular, prominent pigmentary network, peripheral breaks, pseudopodia, radial streaming, depigmentation, regression, black dots.

S.u. malignant melanoma.

1. Debarbieux S et al (2015) Groupe imagerie cutanée non invasive de la Société française de dermatologie. Superficial spreading melanoma. Ann Dermatol Venereol 142:66-69
2. Napolitano L et al (2014) Pigmented Mammary Paget Disease Mimicking Superficial Spreading Melanoma in an Elderly African-American Female. J Cutan Med Surg pii: 7750.2014.14098
3. Toender A et al(2014) Increased incidence of melanoma in situ in Denmark from 1997 to 2011: results from a nationwide population-based study. Melanoma Res 24:488-495