Managing longitudinal melanonychia.

Area of Science:

• Dermatology
• Oncology
• Pathology

Background:

• Longitudinal melanonychia (LM) presents as a pigmented band on the nail, originating from increased melanin production in the nail matrix.
• While often benign, LM can be an early sign of subungual melanoma, necessitating prompt and accurate diagnosis.
• Current diagnostic methods rely on clinical and dermoscopic evaluation, but definitive diagnosis requires histopathological examination.

Purpose of the Study:

• To review the diagnostic challenges and management strategies for longitudinal melanonychia.
• To emphasize the importance of differentiating benign causes from subungual melanoma.
• To discuss optimal biopsy techniques for matrix lesions.

Main Methods:

• Review of clinical, dermoscopic, and histopathological criteria for LM.
• Discussion of biopsy techniques including longitudinal resection, incisional, and tangential biopsies.
• Consideration of complete nail unit resection in suspicious cases.

Main Results:

• Biographical, clinical, and dermoscopic findings can suggest melanoma but are not definitive.
• Matrix biopsy is essential for accurate diagnosis, with techniques chosen to minimize nail dystrophy.
• Early and complete resection of suspicious lesions is recommended.

Conclusions:

• Distinguishing benign LM from subungual melanoma is critical for patient prognosis.
• Matrix biopsy remains the gold standard for definitive diagnosis.
• Appropriate biopsy technique selection is key to accurate diagnosis and preserving nail health.