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.