Gerry is a 65 year old man with a history of sun exposure, and a 20 pack year smoking history who presents with brown nails as seen in the picture beneath.

What are the features on examination of subungal melanoma?

1. Becomes wider, especially at its proximal end (cuticle)
2. Becomes more irregular in pigmentation including light brown, dark brown
3. Extends to involve the adjacent nail fold (Hutchinson sign)
4. May develop a nodule, ulcerate or bleed
5. May cause thinning, cracking or distortion of the nail plate (nail dystrophy).

What percentage of subgunal melanoma are amelanotic?

1. 50%

What are the features of amelanotic subungal melanoma?

1. Ungual melanoma can form a nodule under the nail plate, lifting it up (onycholysis).
2. It may sometimes look like a wart (verrucous).
3. It is usually painless, but
4. an advanced tumourinvading underlying bone may cause severe pain.

What are the causes of brown discolouration of the nail plate

• Fungal infection
• Cigarrete staining
• Drugs – gold / chlorpromazine
• Addisons
• Psoriasis
• Melanoma

Reading

1. Murtaghs General Practice Chapter 129 – http://murtagh.mhmedical.com/content.aspx?bookid=1522&sectionid=116046129
2. Murtaghs Practice Tips – Chapter 8 – Nail Problems – http://murtagh.mhmedical.com/content.aspx?bookid=1920&sectionid=143276631
3. https://www.dermnetnz.org/topics/melanoma-of-nail-unit-images/

Podcast

1. GP Core Content Podcast Episode 150 – Dermatology | Nails