Pigmented Lesions of the Nail Unit

Abstract

Pigmented lesions of the nail unit are commonly encountered in the clinical setting. Yet, they often present a unique challenge to clinicians because of a broad differential diagnosis or unfamiliarity with clinical and histopathologic features. A wide variety of causes exist ranging from benign lesions such as subungual hemorrhage to malignant lesions such as subungual melanoma. Identifying the underlying cause is key to appropriate management and follow-up in these patients. Although emerging clinical tools such as dermoscopy can be very useful in evaluation of these lesions, histopathologic analysis remains the gold standard. In this review, we discuss and provide a summary of important clinical and histopathological concepts of pigmented lesions of the nail unit with special focus on longitudinal melanonychia, melanotic macule, melanocytic nevus, subungual melanoma, along with discussion of some nonmelanocytic lesions.

Oral and nail pigmentations: a useful parallelism for the clinician

“…A detailed medical history can lead the clinician to the correct diagnosis. Moreover, NP often follows the concave conformation of the proximal nail fold and may be removed by scraping the nail plate . No treatment is usually required as the NP tends to fade with nail regrowth.…”

“…Generally, NP has a grayish background characterized by longitudinal multiple bands with regular margins, contours, space and parallelism. Multiple digits are usually involved (Figure a–c).…”

“…Nail nevi mainly occur in children and can be either congenital or acquired, manifesting as a longitudinal melanonychia. Nevi account for nail melanonychia in about 10 % of adults and up to 50 % of children (Figure a, b). With histopathology, nevi are characterized by melanocytic proliferation organized in nests that are mainly located at the dermoepidermal junction .…”

“…Nevi account for nail melanonychia in about 10 % of adults and up to 50 % of children (Figure a, b). With histopathology, nevi are characterized by melanocytic proliferation organized in nests that are mainly located at the dermoepidermal junction . Nevi in children tend to be wider but well‐defined and may be associated with nail plate dystrophy; Hutchinson’s/pseudo Hutchinson’s and triangular signs may be observed in children, but not in adult nevi .…”

Orale und Nagelpigmentierungen: eine für den Kliniker nützliche Parallelität

“…Eine postinflammatorische Hyperpigmentierung tritt sowohl in der Nageleinheit als auch in der Mundhöhle am häufigsten bei den dunklen Hauttypen auf [20,38]. Ein Anstieg der Melaninproduktion ist die häufigste Ursache für eine longitudinale Melanonychie bei Erwachsenen und kann durch vielfältige Trigger ausgelöst werden, unter anderem auch postinflammatorisch [14]. Eine postinflammatorische Hyperpigmentierung entwickelt sich nach meist lange bestehenden entzündlichen Prozessen wie bei Lichen planus des Nagels oder Psoriasis [2,14].…”