Dermoscopy may be used as a noninvasive examination of vulvar melanocytic lesions and can play a role in selection of suspicious pigmented lesions in need of a biopsy. The dermoscopic criteria for benign and malignant lesions on the vulva are not very well established, mainly due to the lack of large case series of such lesions. A recent study revealed that in vulvar melanomas, 60 % of cases had a multicomponent pattern by dermoscopy [7]. The same study revealed that there may be an irregular dermoscopic pattern in vulvar melanomas, with white or white-blue veil, irregularly distributed dots and globules, and atypical vascular pattern [7].

Melanoma can occur on the keratinized surfaces of the vulva, but more often affects the modified mucous membranes of the vulva and the true mucous membranes of the vestibule and the vagina. In one of the large retrospective studies, more than half of the patients presented with melanoma involving the vulvar mucosa (labia minora, urethra, clitoris, introitus, vagina), and in 21 % of the patients, the melanoma was on the epidermal site of the vulva (labia majora or mons pubis). Overall, the most common location is on the labia minora, followed by the labia majora. It is important to emphasize that 20 % of the patients may have multifocal disease at the diagnosis [8]. In rare instances, melanomas can occur on the distal aspect of the urethra and may be visible at the urethral meatus at clinical examination [9].

The female genitalia and especially the vulvar region have one of the highest densities of melanocytes in the body. Approximately 3 % of all melanomas in women occur in the genital region. Among the female genital tract, the most common is vulvar melanoma (76.7 %), followed by vaginal (19.8 %), while cervical melanoma is least common [10]. Despite the sun-protected location and apparent rare incidence, vulvar melanomas are in fact more frequent than other types of cutaneous melanomas, when accounting for the region’s surface in rapport with the entire body surface [11, 12]. The annual incidence of vulvar melanoma is approximately 0.1 per 100,000 per year in the United States. According to one of the largest studies to date using data from the Surveillance, Epidemiology, and End Results (SEER) database, vulvar melanomas occur most often in middle-aged to elderly (median age of 68), postmenopausal white women [13, 14]. Childhood vulvar melanoma is extremely rare [15].

Vulvar melanoma can occur in all skin types. In comparison with nongenital cutaneous-counterpart melanomas, 3.6 % of vulvar melanomas affect black patients, in contrast with only 0.6 % of cutaneous melanomas [14]. As in cutaneous melanomas, family history of melanoma correlates with an increased incidence in vulvar melanoma and may be identified in up to 15 % of cases [16].

When reporting the diagnosis of melanoma, certain prognostic factors and characteristics are usually noted. We will present those parameters with specific comments regarding vulvar melanoma.

The understanding of prognostic factors and their clinical significance in cutaneous melanomas is continuously evolving. The American Joint Committee on Cancer (AJCC) adopted in 2002 a version of the melanoma staging system on the basis of an analysis of 17,600 patients in AJCC Melanoma Staging Database. Recently, in November 2009, a new version of AJCC Melanoma Staging and classification has been released, based on an expanded sample size of the Melanoma Staging Database (over 30,000 patients) and multivariate analysis of different independent prognostic factors [19].

There is variability between different institutions and pathologists regarding the routine reports of histological parameters in melanomas. Some of the reports contain only minimal information (such as tumor thickness and presence or absence of ulceration) while others are very comprehensive. In such detailed reports, although some of the information provided might not be of immediate relevance to a given patient, its importance might become apparent at a later date, especially when used in conjunction with information gathered from large number of patients in prospective or retrospective studies. As an example, mitotic count is now included as an essential histopathological element in the newest version of AJCC Melanoma Staging and classification.

In contrast with the 2002 AJCC Melanoma Staging, the mitotic rate replaces the level of invasion (Clark) in defining T1 categories of cutaneous melanomas. The presence of one or more mitotic figures per square millimeter is now used as one of the two criteria (along with ulceration) for defining T1b-stage melanoma. A possible drawback of applicability of this criterion may be in cases in which there is a very small dermal component. However, it is not recommended by AJCC or College of American Pathologists (CAP) to perform multiple, serial sections with the intent to detect mitotic figures. The tumor thickness is the primary determinant for T staging in both 2002 and 2009 AJCC recommendations for melanoma staging. In the newer 2009 AJCC, recommendation immunohistochemical detection of nodal metastases is included and has to be performed in all the cases in which a metastasis is not obvious in the initial hematoxylin- and eosin-stained sections examined. In such cases, the markers that can be used for immunohistochemical studies may be MART1, Melan A, or HMB45. The number of nodal metastases is the primary determinant for N staging and there is no lower threshold of staging N+ disease (isolated tumor cells and very small tumor deposits should be scored N+). The TNM staging categories for cutaneous melanomas (including vulvar melanoma) that are currently recommended are included in Table 8.1.

Parameters that correlate strongly with the prognosis and should be always mentioned in the report include tumor thickness, number of mitoses per square millimeter, as well as presence or absence of ulceration, lymphovascular, perineural invasion, satellitosis, and regression. In addition, it is recommended to include Clark level (only for vulvar melanomas affecting the cutaneous aspect of the vulva). It is important to emphasize that according to literature, most of the vulvar melanomas at the time of diagnosis are Clark level IV, reach a Breslow thickness ranging between 3.2 and 4.4 mm, have an average of six mitoses per square mm, and a large proportion may be ulcerated [8, 21].

The treatment of choice consists of surgical removal or vulvectomy (hemivulvectomy or radical vulvectomy). There is a trend toward less extensive resection, since there have not been found a difference of survival rates between patients treated with radical vulvectomy and conservative surgery [23] which yields results as good as radial vulvectomies. Obtaining tumor-free resection margins is critical to prevent local recurrence. However, due to the multifocality commonly seen in vulvar melanomas, their frequent amelanotic nature and highly subclinical peripheral extension, complete resection was proven to be a difficult task. Moreover, in up to 20 % of cases, there is a background of atypical junctional melanocytic hyperplasia that makes the assessment of resection margins even more challenging. Frozen section analysis is neither specific nor sensitive for histological evaluation of margins of resection and is not generally indicated. Chemotherapy and radiation therapy add little to overall survival.

The sentinel lymph node biopsy (SLNB) is a less invasive alternative to elective lymph node dissection. The SLNB has a lower associated morbidity and higher sensitivity in detecting lymph node metastases. According to 2009 AJCC recommendations for melanoma staging, immunohistochemical studies have to be performed if tumor is not identified in the routine H&E sections (Fig. 8.7a, b). Up to date the studies analyzing the potential role of SLNB in vulvar melanomas are relatively small but appears that the procedure is capable of identifying patients who have occult lymph node metastases and may benefit from local lymphadenectomy performed in order to prevent distant metastases [24, 25].