A surgical approach to melanonychia striata.

Longitudinal pigmented streaks--melanonychia striata longitudinalis--are discussed from the perspective of a difficult diagnostic problem. These must be differentiated as early as possible from melanoma. The history of this subject and evaluation of patients in the context of various populations are reviewed. Difficult decisions and technical aspects of the approach are outlined. Case presentations contrast multiple different subungual pigmented lesions that enter into the differential diagnosis of these tumors. A larger number of lesions that make up this differential diagnosis are also discussed in addition to the cases. Appropriate biopsy is reviewed. The potential deformities from the biopsy are contrasted with dangers that are associated with some subungual pigmented tumors.