Lentigo maligna melanoma C43.L

Malignant melanoma of elderly people in chronically sun-exposed skin areas. Origins from its precursor lesion, the lentigo maligna.

Brown or brown-black, 0.2-5.0 cm in size (rarely > 5.0 cm), usually bizarrely limited, brown to brown-black, variably coloured plaque (no stain: a stain is not palpable, a plaque is characterized by a papabele raised appearance). The lentigo maligna melanoma develops chronically, "almost unnoticed" on the floor of a lentigo maligna, which usually exists for years.
With increasing duration of the melanoma, the formation of intralesional nodules can occur. This usually differs from the surrounding area in consistency and colour (black).

Further diagnostics:

• Reflected light microscopy: Irregular pigment network with pseudopodia and regressions. The surface texture is no longer preserved.
• High resolution sonography: see below Melanoma, malignant.

• Different guidelines apply to the surgical therapy of lentigo-maligna melanoma than for other malignant melanomas.
• In this type of melanoma, the safety margin recommended for other malignant melanomas can often not be adhered to for cosmetic or general medical reasons in cases of advanced age, multimorbidity or problematic localisation (eyelid, nose, cheek), in tumours with a tumour thickness of Breslow > 1.0 mm.
• The situational operative measure will have to be adapted to acceptable safety distances. In this context, a 3D histology with immunohistological edge control is mandatory in order to create an R0 situation with a reduced safety margin. The study situation justifies this procedure (no increased local recurrence, no reduced survival rate).

Due to the late metastasis, the prognosis is more favourable than for other types of melanoma. 5-JWR=80%.

1. Moehrle M et al (2006) Conventional histology vs. three-dimensional histology in Lentigo maligna melanoma. Br J Dermatol 154: 453-459
2. AWMF(2013) Guideline Program; S3 Guideline "Melanoma Diagnosis, Therapy and Follow-Up Care. www.derma.de.