Spitz Nevus of the Vulva: a Very Rare Presentation of the Genital Region.

Introduction

Spitz nevi of special sites, such as the vulva−, appear rare and can pose a challenge as they may display worrisome clinical-dermoscopic or histopathological features [1-4]. Here we clinically, dermoscopically and histopathologically describe an extremely rare case of Spitz nevus occurring on the vulva of a 47-year-old woman.

Case Presentation

A healthy 47-year-old Italian woman presented with a 2-month history of a rapidly growing lesion on the outer surface of the left labium majus of the genitalia, without pain, pruritus or hemorrhage. Physical examination showed an asymmetric, dark-brown papule, 9 mm in diameter, well circumscribed (Figure 1A). No inguinal lymphadenopathy was revealed. Dermoscopy showed an asymmetric melanocytic lesion with a basically cobblestone pattern, a diffuse blackish pigmentation with grayish shades and large brown-black globules, widely spaced and arranged asymmetrically (Figure 1B). An excision biopsy was made, and histological examination revealed a compound Spitz nevus, characterized by a proliferation of pigmented and epithelioid melanocytes, with no mitoses or atypical features, arranged in dermal nests and partially aligned at the dermo-epidermal junction. Melanocytes showed vesicular nuclei, small nucleoli and a homogeneous cytoplasm with many melanin granules. Mild perilesional lymphocytic infiltration was observed (Figure 2, A_C). Given the peculiar area, recent onset, rapid growth and dermoscopic features, the lesion was completely removed with clear surgical margins, and no recurrence was observed in the 6 months after the excision.

Figure 1

Spitz nevus of the vulva. (A) Clinicalfeatures. (B) Dermoscopicfeatures.

Figure 2

(A) Pigmented melanocytic proliferation expanding superficial dermis with mild epidermal hyperplasia (H%E, scanning magnification ×10). (B) Proliferation of pigmented and epithelioid melanocytes arranged in dermal nests and partially aligned at the dermo-epidermal junction (H&E, scanning magnification ×20). (C) Melanocytes with vesicular nuclei, small nucleoli and a homogeneous cytoplasm with many melanin granules (H&E, scanning magnification ×40).

Discussion

Melanocytic lesions of the female genital area are estimated to occur in 10% to 12% of women and arise mainly in the vulva. These lesions, commonly detected during routine dermatologic or gynecologic examination, include melanocytic nevi, melanosis, Spitz nevi, atypical melanocytic nevi of the genital type, dysplastic nevi and melanomas [4]. Spitz nevi of the vulva are very rare, with only a few cases described in the literature. Polat et al. described a case of an 11-year-old girl with a Spitz nevus on the inner surface of the labium majus of the genitalia [5]. In another retrospective study about the clinical and dermoscopic characteristics of genital melanocytic nevi in children, 2more cases of Spitz nevi on the labia majora have been reported [6]. In adult patients spitzoid lesions may pose diagnostic difficulties as melanoma may mimic Spitz nevi from a morphological point of view. Melanoma is the second most common malignancy of the vulva after squamous cell carcinoma. It generally affects postmenopausal women, with a peak incidence in the sixth and seventh decades of life, but can also affect younger women [4]. Primary vulvar melanoma most frequently develops on the labia majora, followed by the labia minora and clitoral hood. Roughly half of vulvar melanomas arise on glabrous (mucosal) skin, 38% at the hairy-glabrous skin junction, and 13% on hairy skin of the external genitalia [6].

Conclusions

In presence of new onset pigmented papules or nodules in the genital area of women, melanoma should be included in the differential diagnosis and especially in those older than 50 years, histological examination should be performed to rule out melanoma. In this report, given the peculiar area, recent onset, rapid growth and dermoscopic features, surgical excision was warranted. Our case highlights the importance of assessing the genital region during routine skin cancer screening examination, with particular attention about any new or changing lesions.