Abstract
Introduction
The Spitz nevus (SN) is an acquired melanocytic neoplasm composed of epithelioid and/or spindle cells, which tends to develop in childhood. In pediatric patients, it is usually located on the face and neck. Unusual locations have been found in the literature, such as the penis, mouth, and tongue, as well as 2 cases of ungual SN.
Case Report
A 15-year-old male evaluated for dark brown-black longitudinal melanonychia that covered 40% of the nail, with pseudo-Hutchinson’s sign, of 1 year of evolution.
Discussion
The SN accounts for 1% of the melanocytic neoplasms. In the present paper, we show the third case of ungual SN never previously disclosed, which presents a zigzag pattern reported in the literature for its association with the pediatric population.
Keywords: Spitz nevus, Epithelioid and spindle cell nevus, Skin neoplasm, Melanonychia, Melanoma
Established Facts
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The Spitz nevus is an uncommon melanocytic nevus.
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The lesions tend to appear in childhood.
Novel Insights
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Ungual Spitz nevus is an unusual clinical presentation.
Introduction
The Spitz nevus (SN) is a melanocytic neoplasm comprised epithelioid and/or spindle cells, which tends to develop during childhood. These lesions are benign and present as a lone asymptomatic pink or reddish-brown dome-shaped papule or nodule. In pediatric population, it is usually found in the face and neck [1]. Unusual locations have been reported in the literature, such as the penis, mouth, and tongue [2], as well as 2 cases of ungual SN [2, 3]. SN represents a diagnostic and treatment challenge due to its variable morphology [3].
Case Report
A previously healthy 15-year-old male was evaluated for an asymptomatic 1-year evolution dermatosis. Clinical examination demonstrated a lesion on the first upper right nail plate, characterized by longitudinal brown-black melanonychia that covered 40% of the nail, with pseudo-Hutchinson’s sign (Fig. 1). Dermoscopy revealed regular, homogeneous brown and dark brown longitudinal bands in a zigzag pattern (Fig. 2). The lesion showed a significant thickness and pigmentation increase in 3 months.
Fig. 1.
a Longitudinal dark brown-black melanonychia of the nail (first upper right nail plate). b, c Progressive increase in melanonychia, covering 40% of its thickness, with pseudo-Hutchinson’s sign.
Fig. 2.
Linear, regular, brown and dark brown, homogeneous longitudinal bands, with a zigzag pattern (dermoscopy).
Due to the melanonychia thickness increase and pigmentation changes, a biopsy was performed, revealing a symmetrical and well-defined proliferation of melanocytes with spindle and epithelioid appearance, located at the dermal-epithelial junction, and forming perpendicular to the epidermis nests (Fig. 3). With these findings, the definitive diagnosis of ungual SN was established. It was explained to the family that the lesion is a rapidly growing benign nevus, with subsequent stability that requires annual follow-up.
Fig. 3.
Symmetrical and well-defined proliferation of melanocytes with spindle and epithelioid appearance, located at the dermal-epithelial junction, and forming nests perpendicular to the epidermis (H&E stain. ×40 magnification).
Discussion
SN accounts for 1% of the melanocytic neoplasms [4]. Several large case series have documented that 50–75% of lesions diagnosed with histopathology as SN are in patients younger than 20 years old [5, 6]. In children, it is mainly located on the face and neck [1]. Unusual locations have been reported in the literature, such as the penis, mouth, and tongue [2], and two cases of ungual SN have been published so far [2, 3].
In the present paper, we present the third case of ungual SN never previously reported in the literature [2, 3], which was characterized by a zigzag pattern described in melanocyte proliferations with predominance in the pediatric population [7, 8]. Sahin et al. [7] described 5 patients (4 children), one with a histopathological report of melanocytic hyperplasia (lentigo), concluding that this pattern had benign features, mainly in the pediatric population. Nisa et al. [8] showed 4 patients (3 children) with the same dermoscopic pattern, suggesting a nevus of the nail matrix. In children, 75% of cases of longitudinal melanonychia are due to benign melanocytic hyperplasia (mainly junctional nevi), and 25% are due to melanocytic activation [9].
Six dermoscopic patterns have been recognized in SN: starburst (the most frequent), globular, homogeneous, pink/hypopigmented, black pigment nest, and atypical. In their ungual SN case, Ruiz-Arriaga et al. [3] reported a heterogeneous melanonychia pattern comprised by longitudinal bands of different colors and thicknesses.
Due to the wide morphology spectrum, the diagnosis must be confirmed with a biopsy and histopathological and immunochemical evaluation [10]. Histologically, it is described as a well-defined melanocytic proliferation that is arranged in nests, parallel or perpendicular to the epidermis, which can show epithelioid (50% of cases), spindle-like (11%), or both shapes (39%). These nests are usually defined by peripheral crescent-shaped clefts, and even lone epidermal melanocytes may be delimited [3]. Kamino bodies, eosinophilic blood cells comprising basal membrane material, are often present within the epidermis [11, 12]. In the case of nevi of the nail matrix, these are almost always junctional, as in the presented patient [2]. Given the notorious increase in melanonychia clinical features in our patient, a nail biopsy was chosen to rule out melanoma, concluding as a diagnosis an ungual SN, which has been described in the literature in two times, by Domínguez-Cherit et al. [2] in a 2-year-old patient and by Ruiz-Arriaga et al. [3] in a 13-year-old patient. In children, SN is a benign lesion, having a positive prognosis diffusely [10]; therefore, a conservative approach is preferred if possible [6, 13]. The two previously reported cases had expectant management.
Statement of Ethics
The parent gave his written informed consent to publish this paper, including images publication. Ethical approval is not required for this study in accordance with local or national guidelines.
Conflict of Interest Statement
None of the authors have any conflicts of interest or financial ties to disclose.
Funding Sources
This research received nonspecific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Author Contributions
Drafting of the manuscript: I.A.-A. and A.V.-A.; critical revision of the manuscript: C.P.-L.; and examination of biopsy: S.T.-C.
Funding Statement
This research received nonspecific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Data Availability Statement
All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.