Thursday, January 24, 9pm EST
Article discussed: Pigmented Lesions of the Nail Unit
Authors: Nevares-Pomales O, Sarriera-Lazaro C, Barrera-Llaurador J, Santiago-Vazquez M, Lugo-Fagundo N, Sanchez JE, Sanchez JL.
Summary prepared by Patrick Rush, DO (@DrPatrickRush)
Journal Club summary:
This month’s journal club article discussed a topic that gives many of us much consternation, pigmented lesions of the nail unit. The article was a good overall review in many regards; there was discussion (with images) of the clinical features of melanocytic lesions and the concerning signs, as well as a review of the epidemiology, histology, and molecular findings. The learning objectives for the article were very well laid out, and there are accompanying CME questions for obtaining AMA PRA Category 1 credits.
It was a lively discussion, and those active in the discussion overall agreed with the author’s summary and findings.
There were a few take home points from the paper and subsequent discussion, which touched on all aspects:
- Proximal nail matrix = predominantly dormant melanocytes
- Distal nail matrix = active and dormant melanocytes (more likely for a melanocytic lesion to arise within this zone)
- Melanocytic macule more common in adults
- Nevi more common in children
- Longitudinal melanonychia not always due to a melanocytic lesion (Fungus, drugs, trauma, infection, etc can be causative)
- Amelanotic subungual melanoma has been reported at rates between 15-50% (while they only comprise 2-8% of melanomas at other sites)
- Many seem to groan with nail clippings to evaluate for a melanocytic lesion
- If clippings are sent, if negative they will usually be emblazoned with a caveat in an comment
- Most peoples malignant lesions have been composed of melanoma in situ with invasive melanoma making up the minority.
- SOX10 not as useful in the nail unit as in other parts of the body
- Mart-1 / Melan A are preferred, and felt to work better
- Some also order a Fontana Mason in addition
- Subungual melanoma more commonly harbor KIT mutations
- Predictions through immunohistochemistry has thus failed to be predictive of molecular aberrations
- Gold standard for interrogation of KIT mutations remains molecular analysis
Some Highlights from the Evening:
Top: nail plate chromomycosis
Bottom: nail plate onychomycosis
The conversations were great again, with a nice mix of Dermatologists and Pathologists from all over the world. Hope to see you again next time!