Subungual Pigmented Nevus: Evaluation of DNA Ploidy in Six Cases

Abstract

The discrimination between subungual pigmented nevus and subungual melanoma in situ is still a clinical problem. We measured DNA ploidy in six cases of subungual melanotic lesions which exhibited the features of subungual pigmented nevus or lentigo simplex histologically. Five cases presented a diploid pattern with or without a slight increase of hyperdiploid cells. One case presented a polyploid pattern; it also exhibited histologically abnormal melanocytes with large nuclei and pigment-filled elongated dendrites. The DNA ploidy pattern and histologic features suggest that the lesion of this latter case contains abnormal melanocytes which probably have the potential to undergo a malignant transformation into a subungual melanoma. DNA ploidy analysis, therefore, is likely to provide information for evaluating the biologic behavior of subungual melanotic lesions.

Malignant Melanoma In situ Arising in the Nail Unit of a Child

“…However, there are no proven cases of such malignant melanomas arising in children reported so far, except for a few probable cases (6,7). In this report, a patient that is considered clinically and histopathologically to be a very rare case of malignant melanoma in situ arising in the nail unit of a child is presented, and the significance of the early diagnosis is discussed.…”

“…Therefore, if the theory that chronic stimuli on the melanocytic nevus can cause malignant melanoma (19,20) is correct, melanocytic nevus of the nail unit is indeed a risk factor for malignant melanoma, whether the lesion clinically loses its pigment or not, as long as nevus cells persist. As Asahina and others (7) indicated in their study of subungual melanocytic lesions with DNA analysis, malignancy cannot be denied even in children.…”

“…Malignant melanomas of the nail unit (subungual malignant melanomas) are more frequently found in blacks and orientals than in whites among the total population of patients with malignant melanomas (1)(2)(3)(4)(5). However, there are no proven cases of such malignant melanomas arising in children reported so far, except for a few probable cases (6,7). In this report, a patient that is considered clinically and histopathologically to be a very rare case of malignant melanoma in situ arising in the nail unit of a child is presented, and the significance of the early diagnosis is discussed.…”

A Subungual Nevus in a Filipino Child

“…Reported cases of histologically proven subungual nevi are few. Most of these lesions have occurred in children (Table 1) (1,2,6–18). Goettmann‐Bonvallot et al (18) evaluated 40 children (25 girls, 15 boys) ages 2–16 years with melanonychia.…”

“…Subungual melanocytic nevi are considered rare and only a few histologically proven pediatric cases have been reported in the literature (1,2). We describe a 2.5‐year‐old Filipino girl with a subungual junctional nevus.…”