Punch Biopsy for Toenails
A 38 year old female presented to the clinic for a new enlarging
black spot under her toe nail for six weeks. She declined trauma of any kind. Notable history includes strong family
history of melanoma. Her mother had two melanomas, including one on her toe.
Upon removal of the tumor of the toe, her mother lost the second, third and
fourth digits of the left foot. 
Upon examination of the left great toe was a
4mm irregularly shaped black macule in the medial Lunula. Dermascope
microscopy offered little if no assistance in determining trauma versus
pigment. Therefore, with the combination of the patient's certainty of no
injury and her mother's melanoma, I opted to perform a 3mm punch biospy.
I always present the options to the patient
for biopsy of the toenail to rule out a Melanoma. The first option is a punch
biopsy that results in a small hole in the nail that eventually will grow out.
The second choice is a total nail removal and then biospy of the lesion. I
personally would rather keep my nail with a small hole then have the entire
nail removed and wait almost a year for regrowth. We women love our nail
polishes! In this case, the patient chose to have the punch biopsy through the
nail.
I prefer a digital block and then let the
patient sit for ten minutes to ensure anesthesia has settled. To perform a nail punch biopsy you must
twist and push with much more pressure than you would imagine. Keep twisting
with pressure until you hear a crack; that is the signal the blade has ruptured
the nail. Keep twisting deeper through the Hyponchium and nailbed in order to
get a proper sample. The entire specimen including the nail is submitted to the
dermatopathologist.
I am happy to report this biopsy came back
as a hematoma and no evidence of melanocytic activity.