ReviewDiagnosis and management of nail pigmentations
Section snippets
Personal history
The physician should try and elicit a history as to whether the pigment was present since birth or acquired. Furthermore, the history of its duration, history of what made the patient first become aware of it, and whether the patient has observed any change in the nail lesion may provide clues for the correct diagnosis. Many patients find it difficult to verbally describe what the nail looked like and how it had changed over time. To overcome this problem we have found it useful to allow the
Differential diagnosis of nail pigmentation
The first and most important task necessary to diagnose the cause of nail pigmentation is to differentiate whether the pigment is of melanocytic or nonmelanocytic origin.2 In most cases this task can be accomplished by clinical inspection and examination with dermoscopy. In nonmelanocytic lesions such as fungal infections or subungual hematoma, the pigment tends to be distributed homogenously. In melanocytic lesions, the melanin is found in cellular inclusions,10 which can be easily identified
Which lesions should be biopsied?
Any lesion with an irregular dermoscopy pattern should be biopsied.
Independent from the morphology seen under dermoscopy the following situations should alert the physician to the possibility of malignancy14, 19:
- 1.
Isolated pigmented band on a single digit that develops during the fourth to sixth decade of life. Although melanoma can be seen in children it is a very rare event.
- 2.
Nail pigmentation that develops abruptly in a previously normal nail plate.
- 3.
Pigmentation that suddenly becomes darker or
Biopsy techniques for nail pigmentation
The choice of the biopsy technique for longitudinal melanonychia depends on many factors such as location, degree of suspicion,14, 19, 46, 47 and:
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Presence of periungual pigmentation or Hutchinson's sign (Fig 13).
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Location of the band within the nail.
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Origin of the band in the matrix. In other words, is the origin of the pigment in the proximal or distal nail matrix?
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Width of the band.
- 1.
Periungual pigmentation or pigmentation of the nailfold should be viewed as a sign of malignancy unless proven
Melanoma in situ
The surgical treatment of an in situ melanoma requires the complete surgical removal of the nail apparatus including nail plate, nail bed, and nail matrix. The resulting defect can be repaired either with a split- or full-thickness skin graft.48, 49, 50, 51, 52 Although it is possible to allow wound healing by secondary intention, this will often result in a surface that is not smooth and can have spicules of keratinizing tissue and, thus, is not as comfortable for the patient as the results
Conclusion
Longitudinal nail pigmentation occurs frequently enough that every dermatologist will be confronted with this condition in his or her practice. The differential diagnosis is fairly broad and includes entities listed in Table I. Each one of these conditions poses particular management issues. The use of dermoscopy can assist in the evaluation and possible diagnosis of nail pigmentation. It should be performed to help identify the type of pigment and to determine the origin of the pigment. This
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Funding sources: None.
Conflicts of interest: None declared.