On the first day of the 2023 AAD Annual Meeting, Judith Dominguez-Cherit, MD, shared recent developments and insights during her session, “Update: Benign Nail Neoplasms.”

To start, she went over recent case studies that highlighted the many surprises benign neoplasm can present physicians. These included superficial acral fibromyxoma in the nail matrix, subungual eccrine poroma, 2 tumors presented in 1 patient (superficial acral fibromyxoma and angioleiomyoma), and pigmented onychomatricoma (often confused with either melanoma or pigmented squamous cell carcinoma). Additionally, she presented a study highlighting approaches to pediatric melanonychia.

“As nail matrix nevus is a benign tumor, it is important to discuss management of melanonychia in children and teenagers,” she stated.

She went on to share that the most common cause of pediatric melanonychia striata is nail matrix, which is presented as irregular, wide pigment bands in addition to nail dystrophy and Hutchinson sign. She added malignant causes were very rarely reported. She then shared that fish and P16 are possible adjuncts for distinguishing benign and malignant causes of pediatric melanonychia striata.

She continued to highlight case studies, starting with a presentation of subungual atypical lentiginous melanocytic proliferations (pigmented nail lesions) in children and teenagers. Particularly, how these lesions are histologically undistinguishable compared with subungual melanoma in adults. She added that, when dealing with nail pigmentation in children, treatment should be completely different from that in adults.

“Some of them are atypical lentiginous proliferations, so complete nail excision is recommended,” she noted.

Next, she shared images of zigzag longitudinal melanonychia, noting the zigzag pattern as a disappearance of the melanonychia with histology linked to lentigo.

She transitioned into pachymelanonychia and longitudinal pachyonychia, especially focusing on onychocytic matricoma, which was presented as pigmented or longitudinal bands with distal pachyonychia, also known as ungueal seborrheic keratosis.

Dr Dominguez-Cherit then presented onycholemmal horn, which consists of:

• A nodule or horn at the edge of the nail plate
• A low growth that can invade the nail matrix
• A pain when undergoing manipulation

Finally, Dr Dominguez-Cherit shared an additional study highlighting angiolymphoid hyperplasia with eosinophilia, adding that only 5 cases were present in the nail unit. When it comes to benign neoplasm, there are possible surprises on the horizon.

“So, if a single nail is involved you should think about a nail tumor,” she concluded.

Reference
Dominguez-Cherit J. Update: benign nail neoplasms. Presented at: AAD Annual Meeting; March 17–21, 2023; New Orleans, LA.