Pigmented vulvar lesions are found in roughly one out of every ten women and span a wide spectrum from completely harmless color changes to, rarely, melanoma.1PubMed. Vulvar nevi, melanosis, and melanoma: an epidemiologic, clinical, and histopathologic review The vast majority are benign, but because benign and malignant lesions can look strikingly similar on vulvar skin, the clinical challenge lies in telling them apart. That overlap is what makes this topic worth understanding beyond a simple “most are fine.”
How Common They Are and What They Include
Studies in white women put the prevalence of pigmented vulvar lesions at about 10 to 12 percent, with only around 2 percent of those being true moles (nevocellular nevi).2PubMed. Pigmented lesions of the vulva The term “pigmented vulvar lesion” covers a broad group. On the melanocytic side, you have melanosis (flat dark patches caused by extra pigment in the skin’s baseline cells), moles, and melanoma. On the nonmelanocytic side, conditions like seborrheic keratoses, angiokeratomas, and post-inflammatory darkening after irritation or trauma can all produce visible pigmentation. Because vulvar skin is not routinely examined with the same scrutiny as, say, the face or arms, many of these go unnoticed for years and only come to attention during a gynecologic exam or when someone checks themselves at home.
Vulvar Melanosis
Melanosis is the most common melanocytic cause of vulvar pigmentation. These are flat, often irregularly shaped patches that result from increased melanin in the basal layer of the skin, without any harmful growth of the pigment-producing cells themselves. A large study tracking 129 women with vulvar melanosis over a median of 13 years found that none of the lesions turned malignant during follow-up.3PubMed Central. Clinical and Dermoscopic Features of Vulvar Melanosis Over the Last 20 Years The most common location was the labia minora, followed by the labia majora.
What makes melanosis tricky is that it can look alarming to the naked eye. An early study of genital melanotic macules described lesions up to 2 centimeters across that were multifocal, irregular in outline, and variably pigmented. Most were flagged as “clinically atypical” on visual inspection alone, yet microscopic examination revealed no abnormal melanocyte behavior at all.4Journal of the American Academy of Dermatology. Genital lentiginosis: A clinical and histopathologic study In other words, these patches often look worse than they are. About 30 percent of cases in the long-term study did show some change in size or color after initial diagnosis, but all eventually stabilized without any sign of malignancy.5PubMed Central. Clinical and Dermoscopic Features of Vulvar Melanosis Over the Last 20 Years Hormonal influences may play a role: roughly two-thirds of the women in that cohort were premenopausal, and a similar proportion had used some form of hormone therapy.
Vulvar Nevi and the “Special Site” Problem
Moles (nevi) on vulvar skin fall into a category pathologists call “nevi of special sites.” This label exists because when a pathologist looks at a genital mole under the microscope, it can display features that mimic dysplasia or even melanoma, including asymmetric growth patterns, large cells, and prominent nucleoli. These microscopic red flags are well-documented, but the clinical behavior of these moles is benign.6Modern Pathology. Precursors to melanoma and their mimics: nevi of special sites
A study of 56 atypical genital nevi, most arising on the vulva in women with a median age of 26, confirmed this. Despite occasionally striking microscopic atypia, follow-up over as long as 16 years showed only one recurrence and no progression to melanoma.7The American Journal of Surgical Pathology. Atypical Genital Nevi: A Clinicopathologic Analysis of 56 Cases The practical takeaway is that a pathology report describing “atypical” features in a vulvar mole does not automatically mean something dangerous is happening. These nevi are most often small, well-bordered, and uniformly pigmented when viewed clinically. They are frequently removed incidentally during pregnancy or delivery rather than because they raised a clinical alarm.8Modern Pathology. Precursors to melanoma and their mimics: nevi of special sites
The confusion this causes is real. A pathologist unfamiliar with genital nevi might read the slide as worrisome, triggering further surgery or anxiety. Yet comparative studies have shown that the vast majority of vulvar nevi are microscopically indistinguishable from ordinary skin moles elsewhere on the body; only a small subset exhibit those misleading features.9Modern Pathology. Precursors to melanoma and their mimics: nevi of special sites
How Dermoscopy Helps Tell Them Apart
Because visual inspection alone cannot reliably distinguish benign from malignant pigmented vulvar lesions, dermoscopy, which uses a handheld magnifying device with polarized light, has become a valuable screening step. Different types of lesions tend to display characteristic patterns under dermoscopy. Melanosis frequently shows a parallel pattern or a ring-like pattern, with the ring-like pattern being essentially exclusive to melanosis and not seen in moles or melanoma.10PubMed Central. Dermoscopic and clinical features of pigmented skin lesions of the genital area One retrospective study found parallel and ring patterns in about 73 percent of genital melanosis cases, while nevi more commonly showed reticular, globular, homogeneous, or cobblestone patterns.11European Journal of Gynaecological Oncology. Vulvar pigmented lesions: a retrospective study and a review of literature
Melanoma stands apart. In studies of dermoscopic patterns, vulvar melanomas consistently displayed a multicomponent pattern, meaning they showed multiple different structural elements simultaneously rather than one dominant pattern.12British Journal of Dermatology. Features of pigmented vulval lesions on dermoscopy Other dermoscopic red flags for melanoma included blue-white veil, irregularly distributed dots and globules, and atypical blood vessel patterns. One analysis of 128 vulvar lesions confirmed that all melanomas in the sample showed a multicomponent pattern, while melanotic macules, despite sometimes looking similar to melanoma clinically, had distinctly different dermoscopic features.13Dermatology. Dermoscopy of Pigmented Lesions of the Vulva: A Retrospective Morphological Study Features like blue-white veil and irregular dots were also seen exclusively in atypical nevi within the genital area, prompting the recommendation that any lesion showing those findings undergo biopsy.14PubMed Central. Dermoscopic and clinical features of pigmented skin lesions of the genital area
The general clinical stance is that clinicians should have a low threshold for biopsy on genital skin. Pigmented lesions are harder to diagnose visually in this area than on other parts of the body, and if something does not look classic for a benign condition, tissue sampling is the safest path.15Dermatologic Therapy. Pigmented vulvar lesions
Vulvar Melanoma
Vulvar melanoma is rare, but it accounts for a disproportionate share of serious outcomes because it tends to be caught late. It represents a small fraction of all melanomas and all vulvar cancers, yet because of delayed recognition, it carries a poor prognosis with significant illness and death.16PubMed. Vulvar nevi, melanosis, and melanoma: an epidemiologic, clinical, and histopathologic review One factor is anatomical: the vulva is simply not examined as routinely or casually as sun-exposed skin. Another is the visual overlap with melanosis and nevi, which can lead both patients and clinicians to dismiss early melanomas as benign patches. Research on vulvar cancer more broadly has documented diagnostic delays averaging close to a year when preceding symptoms or conditions were initially attributed to something else.17PubMed Central. Potential delay in the diagnosis of vulvar cancer and associated risk factors in women treated in German gynecological practices
Newer laboratory tools are helping pathologists draw a clearer line between melanoma and benign mimics. An immunohistochemical marker called PRAME has shown particular promise. In one study, strong nuclear PRAME staining was found in 85 percent of vulvar and vaginal melanomas but in none of the benign nevi tested.18International Journal of Gynecological Pathology. PRAME Immunohistochemistry for Distinguishing Vulvar and Vaginal Melanoma From Benign Melanocytic Nevi PRAME also proved useful for evaluating surgical margins: it identified melanoma involvement at margins in cases originally reported as negative, which could change management decisions. A separate study found PRAME had perfect specificity for melanoma (no false positives among benign lesions), while another melanocyte marker, SOX10, was positive in both melanoma and benign lesions and therefore less useful for distinguishing the two.19PubMed Central. Diagnostic Utility of PRAME and SOX10 Immunostaining for Vulvar Melanocytic Lesions
Why Vulvar Melanoma Is Molecularly Different From Skin Melanoma
If you are familiar with how cutaneous melanoma is treated, vulvar melanoma does not follow the same playbook. The genetic mutations driving vulvar melanoma differ from those in sun-damaged skin melanomas, and those differences matter for which targeted therapies might work. One molecular study found that BRAF mutations, which drive the majority of cutaneous melanomas and are targeted by widely used drugs, were the most frequently mutated gene in vulvar and vaginal melanomas at about 26 percent, but the profile was otherwise distinct from sun-exposed skin tumors.20PubMed. Vulvar and vaginal melanoma: A unique subclass of mucosal melanoma based on a comprehensive molecular analysis of 51 cases compared with 2253 cases of nongynecologic melanoma KIT mutations were found at a notably higher rate in vulvar melanomas, around 18 to 22 percent, compared with only about 3 percent in typical skin melanomas.21PubMed. Vulvar and vaginal melanoma: A unique subclass of mucosal melanoma based on a comprehensive molecular analysis of 51 cases compared with 2253 cases of nongynecologic melanoma An earlier study confirmed the absence of BRAF mutations in its vulvar melanoma cohort and found NRAS and KIT changes at roughly equal frequency.22Modern Pathology. Comparison of molecular abnormalities in vulvar and vaginal melanomas
The relatively high rate of KIT mutations has opened a treatment angle. KIT inhibitors like imatinib have shown responses in select vulvar melanoma cases, particularly when specific KIT mutation subtypes are present. Case reports have documented dramatic tumor shrinkage when imatinib is used in patients whose tumors harbor mutations known to respond to the drug.23PubMed Central. Current Status and Prospects of Immunotherapy for Gynecologic Melanoma The response depends heavily on which KIT mutation is involved, though. Some subtypes that cause resistance to imatinib in other cancers also predict resistance in melanoma. Combination approaches pairing immune checkpoint therapy with KIT inhibitors are under investigation, with early signals suggesting the immune drugs may enhance the effects of the targeted therapy.24PubMed Central. Current Status and Prospects of Immunotherapy for Gynecologic Melanoma
Sentinel Lymph Node Biopsy in Vulvar Melanoma
Staging vulvar melanoma often involves checking nearby lymph nodes for spread. Sentinel lymph node biopsy, which identifies and samples the first node draining from the tumor site, has been explored as a less invasive alternative to full lymph node removal. An early study showed the technique could detect hidden lymph node involvement, potentially sparing patients from full lymphadenectomy when the sentinel node is clean. However, the same data raised a cautionary signal: the procedure appeared to increase the risk of in-transit metastases, particularly in thicker melanomas.25PubMed. Vulvar melanoma: is there a role for sentinel lymph node biopsy? Based on that evidence, the authors recommended restricting sentinel node biopsy to melanomas of intermediate thickness and conducting further research only within controlled clinical trials. The technique remains a subject of active study rather than settled standard practice for vulvar melanoma.
Conditions That Mimic Pigmented Vulvar Lesions
Not everything that looks dark on the vulva originates from melanocytes. Several nonmelanocytic conditions produce pigmented or dark-appearing spots that can cause confusion. Angiokeratomas of Fordyce are a well-known example: these are small, dark red to black papules caused by dilated blood vessels near the skin surface rather than by pigment cells. They can bleed when touched, which understandably alarms anyone who notices them. A case series described a woman presenting with painless dark raised vulvar lesions that turned out to be angiokeratomas, with biopsy confirming dilated blood vessels and overlying skin thickening but no melanocytic involvement whatsoever.26PubMed Central. Unusual Genital Wart Lesions: A Case Series on Angiokeratoma of Fordyce Seborrheic keratoses, which are common harmless skin growths in older adults, can also appear on the vulva and carry pigmentation. Post-inflammatory hyperpigmentation after an episode of irritation, infection, or eczema is another frequent cause of dark patches. Dermoscopic studies have found that seborrheic keratoses and vulvar intraepithelial neoplasia share a distinctive cerebriform (brain-like) pattern not seen in melanocytic lesions, providing another useful diagnostic clue.27British Journal of Dermatology. Features of pigmented vulval lesions on dermoscopy
Pigmented Vulvar Lesions in Children and Adolescents
Parents who notice a dark spot on a young girl’s vulva face an especially anxious situation, but the evidence here is reassuring. A scoping review combining published literature with Dutch population data concluded that vulvar melanoma in children and adolescents is extremely rare.28PubMed Central. A Scoping Review and Population Study Regarding Prevalence and Histopathology of Juvenile Vulvar Melanocytic Lesions. A Recommendation Just as in adults, juvenile vulvar moles can show atypical microscopic features that look suspicious under the microscope but follow a benign course. The review’s authors went a step further than most, concluding that excision biopsies in this age group are generally not indicated even when atypical features are observed on histology.29PubMed Central. A Scoping Review and Population Study Regarding Prevalence and Histopathology of Juvenile Vulvar Melanocytic Lesions. A Recommendation This is a meaningful shift from the reflexive biopsy-everything approach, acknowledging that surgical intervention on a child’s vulva carries its own physical and psychological costs that are difficult to justify when the underlying risk of melanoma is vanishingly small.
Living After Vulvar Cancer Treatment
For the small number of patients who do face a vulvar cancer diagnosis, including melanoma, the aftermath of treatment carries lasting effects that are often underappreciated. A Norwegian cross-sectional study found that only about 20 percent of vulvar cancer survivors were sexually active, compared with roughly 69 percent of women in a normative sample. Survivors reported significantly more pain during sexual activity, more vaginal narrowing, and less enjoyment of sex.30PubMed Central. Long‐term quality of life, vulvar symptoms, and sexual functioning: A cross‐sectional study of Norwegian vulvar cancer survivors Beyond sexual function, psychosocial consequences include altered body image, shame, anxiety, and persistent fatigue.31International Journal of Gynecological Cancer. Perceived Health-Related Quality of Life in Women With Vulvar Neoplasia: A Cross Sectional Study These are not minor side notes. They speak to why early and accurate differentiation between benign pigmented lesions and melanoma matters so much: the treatment for vulvar melanoma, typically surgical excision that may include lymph node procedures, can permanently reshape a person’s physical and emotional relationship with their body. Avoiding unnecessary surgery on benign lesions is just as important as catching the rare malignancy early.