Renal Transplant Patient with a Black Toe

The patient is a 70 yo man who had a renal transplant around 10 years ago.  His immunosuppression consists of oral tacrolimus and prednisone, and he is seen annually by a dermatologist.  He had a 3 cm superficial squamous cell carcinoma ofhis scalp 5 years ago that was treated successfully with topical 5FU.

O/E: The current exam revealed a black area under the nail of the second toe on the left foot.  He said it's been like his for around a year and has not changed much.

Clinical and Dermatoscopic Images:

Diagnosis and Discussion:
While I am pretty certain that this is a subungual hematoma; if his history is accurate that may be worrisome.  There is little downside to removing the nail and biopsying the nail base if it is pigmented and this was scheduled in a week's time.  The fact that this is Morton's toe also favors subungual hematoma.

Subungual Pigmentation

The patient is a 49 yo woman who noted a discolored right great toe nail for ~ a week.  After a web search she became quite agitated and presented at the office as a walk-in patient.  The area was painless and there was no history of trauma.

O/E:  The patient is an anxious-appearing Korean woman. There was a dark purple area at the proximal and lateral portion of the right great toe nail.  Dermoscopically no brown or black color could be seen.  The nail was scraped down and the base appeared reddish.

Unfortunately the second photograph is a bit blurry.

Impression:  She short history and the pigment suggest subungual hematoma.  It would be unusual for a subungual melanoma to present this rapidly.

Plan:  I will follow this.  I expect it will take many months for this to grow out.

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.

References:
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

R/O Subungual Melanoma

70 yo man referred for suspected subungual melanoma.

HPI: The patient is a retired engineer with a one month history of subungual pigmentation. He suffers from Waldenstrom's macroglobulinemia and peripheral neuropathy. If he had injured his toe, he would not know.

O/E: The left middle toenail shows brown-blackish subungual pigmentation. It was difficult to appreciate if this was melanin or blood both clinically or dermoscopically. Hutshinson's sign is negative.


Dermoscopy before 3 mm punch biopsy

Diagnosis: Probably subungual hematoma. Need to r/o melanoma.

Procedure: Modification of Haneke Technique.

1. Patient soaks foot in warm water for 20 - 30 minutes
2. Carefully drive a 3 mm punch through the nail with care not to cut into the nail bed.
3. Lift off the cut disk of nail and observe the nail bed.


Dermoscopy after 3 mm punch biopsy and H2O2 to defect

In this case, what appeared to be dried blood was present. The area was cleaned with hydrogen peroxide and a normal appearing nail bed was see. There was no pigment noted. Dr. Hanecke's technique utilizes a Hemocult stick to test scraping from underside of nail, however, our strips were outdated and not reliable.

Note: Dr. Eckhart Haneke pioneered this technique but is not acknowledged in the literature. Here are his comments to this case: "Thank you very much for your email and the links, which I saw for the first time. Thank you also for giving me the credit.
You are completely right that we do not even need the hemoccult test strip for the correct diagnosis, but it is very convincing and impresses the patient. And of course, it is one more proof.
Also clinically, as this is no streaky lesion a melanoma is improbable - however, a very fast growing melanoma can appear like this.
When you apply hydrogen peroxide and the pigment disappears this is due to the hemodestructive action of H2O2 on erythrocytes: hemoglobin has a pseudocatalase action splitting H202 into H2O and O. That is why hydrogen peroxide is also a very good disinfective agent and I use it to cleanse my dermatosurgery field from blood."