Pigmented lesions of the nail apparatus

Abstract

Biopsy of the nail unit is often undertaken for the evaluation of irregular pigmentation, especially longitudinal melanonychia (pigmented bands). There are a variety of barriers to arriving at a diagnostic conclusion, however. The nail plate covers the source of the pigmentation. Clinical cues can thus be misleading. There may be a lack of familiarity with nail anatomy and biopsy techniques on the part of the clinician. Suboptimal specimens may thus result. Many pathologists also lack familiarity with normal nail unit histology and pathology, and many pathology laboratories lack experience with respect to handling of these specimens, which often contain both delicate tissue and a hard nail plate, leading to technical shortcomings.