Atopic Dermatitis: a Short Summary
Nail Nevi and Melanoma
-General Facts
- the lunula is part of the matrix and a melanocytic primary lesion implicates lunula involvement
- slow longitudinal thickening is a characteristic of melanoma (or at least it needs to be ruled out)
-Signs that a lesion is not melanocytic
- arcuate white line associated with redness or pigmentation: in 98% of cases in is traumatic in origin (Hematoma). The ridge can also be felt by pulling back the nail fold
- proximal clearing: it’s not melanocytic. The proximal nail fold can be pushed back.
- hemorrhagic dots
- colour that does not extend to the lateral edge.
-Dermoscopy is useful but only afford a correct diagnosis in 50% of cases. It all has to do with detecting a regular pattern or an irregular pattern,
- Regular Pattern: Brown Longitudinal parallel lines with regular spacing and thickness
- Irregular Pattern: The band compromises multiple longitudinal brown to black lines with irregular spacing and thickness and disruption of parallelism (Braun RP, Baran R, Le Gal FA)
-A biopsy is warranted for the following:
- evolving pigmented streak (3-6 month evaluation period)
- Heterogenous in pigment in width or length
- Involvement of proximal nail fold (Hutchinson’s sign)
- Destruction of Nail
- Beyond medium darkness (dark)
- Isolated pigmented band appearing in a 40 to 60 years old
- Family history of melanoma (controversial)
Make sure that the biopsy is thorough and not just a superficial sample. Getting a report of hyperkeratosis can actually miss the bulk of the lesion and miss the diagnosis.
pigmented longitudinal streaks in children are almost always benign
-Excised melanoma is better if possible than amputation. No recurrence is the norm according to breslow thickness (which is the same as anywhere else on the body).
-If there is a single digit dystrophy resembling psoriasis or Lichen Planus (LP), it could be amelanotic melanoma or squamous cell carcinoma. Psoriasis or LP tend to affect multiple digits.
Contributors:
Dr Christophe HSU – dermatologist. Geneva, Switzerland
Source of Information. CO9. De Berker. Hair and Nail Diseases. 2011 (10) – 20th Annual Congress of the EADV (European Academy of Dermatology and Venerology) – Lisbon (Lisboa), Portugal
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