Tuesday, March 17, 2015

Dermatoscopic Dilemmas

The dermatoscope is a source of endless wonder.  Here are two cases seen in the past week.

1. Congenital Nevus of Special Site
This 5 month old bi-racial (Black/Caucasian) foster infant was noted to have a slowly enlarging pigmented lesion in his left crural fold since around one month of age.

photo taken by Dr. Yoon Cohen
Question/Comment: Would anyone do anything other than follow this child?  Is the gray veil significant? The symmetrically distributed brown clods are to my mind markers for a benign growing nevus (cobblestone pattern).  There is no pertinent literature about growth in small congenital nevi.  Melanoma, in this age group and ethnicity, is exceedingly rare.

2. Unusual Subungual Hematoma
A 72 yo woman noted nail pigmentation that appeared shortly after knee replacement surgery.  I do not know if she had been anticoagulated after surgery, but the information would help.  The subungual color under the cuticle may be an example of a "pseudo-Hutchinson sign."
1 month follow-up
Note:  The one month follow-up shows distal progression of pigmented area confirming the clinical impression of subungual hematoma.

Question/Comment: The fact that this appeared shortly after surgery strongly suggests trauma rather than neoplasia.  If the patient was anticoagulated during surgery, that would be one more helpful historical fact.  The pattern of the long band could be called the "tadpole sign" -- I wonder if it is specific for subungual hematoma.

1. Precursors to melanoma and their mimics: nevi of special sites.
Elder DE. Precursors to melanoma and their mimics: nevi of special sites. Mod Pathol. 2006 Feb;19 Suppl 2:S4-20.  Free Full Text.
2. Dermnet.nz.org has good sections on dermtoscopy: Introduction to Dermatoscopy   Dermatoscopic Features 

3. Overview of Nail Dermatoscopy

No comments:

Post a Comment

We welcome your comments. We endeavor to serve your patients and you. If you want us to respond, please add your name and email address. Some people have trouble uploading comments. In that case, please send comments directly to djelpern@gmail.com. Thank you.