Vulvar Dermoscopy: Pigmented Lesions and Mucosal Pathology

01Vulvar melanosis is the most common pigmented vulvar finding, accounting for the majority of pigmented vulvar lesions referred to dermatology. It presents as one or more flat, asymmetric, brown to brown-black macules on the labia minora, vestibule, or labia majora. Dermoscopy of vulvar melanosis (Ferrari 2008, Cengiz 2013) shows a parallel pattern with parallel brown lines, structureless brown areas, ring-like or annular structures, or a combination, all on a homogeneous brown background. The pattern is symmetric or organized despite clinically irregular borders, and there are no melanoma-specific features such as multiple colors, blue-white veil, or atypical vessels. Lesions can be large (several centimeters) and asymmetric and still be benign melanosis.

02Vulvar nevi follow phenotype with anatomy. On glabrous mucosal vulvar skin (vestibule, inner labia minora) they show parallel furrow patterns analogous to acral nevi, with light brown lines along the furrows. On hair-bearing labia majora they show globular or homogeneous patterns similar to nevi elsewhere on the body. Atypical genital nevi (sometimes labeled MUSK or MUSK-1, melanocytic lesions of unusual sites with kissing distribution or atypical features) occur in adolescents and young women and require careful clinical-pathologic correlation; expert pathology review is recommended before classifying as melanoma.

03Vulvar melanoma represents around 5 to 10% of all vulvar cancers, with median age at diagnosis around 60. Dermoscopy shows a multicomponent pattern: multiple colors (brown, black, blue, grey, red), asymmetric pigment distribution, blue-white veil, atypical vessels (irregular linear, dotted, polymorphic), and a disorganized overall pattern that breaks the parallel or organized rules of vulvar melanosis. Acral-pattern signs such as the parallel ridge pattern (analogous to plantar melanoma) can occur on glabrous mucosal vulva. Mucosal melanoma is biologically distinct from cutaneous melanoma, with less BRAF and more KIT, NRAS, and SF3B1 mutations, lower response to immunotherapy, and higher metastatic risk per stage.

04Vulvar lichen sclerosus (LSA) is one of the most clinically important non-pigmented vulvar conditions because it carries roughly a 4 to 6% lifetime risk of progression to differentiated VIN and squamous cell carcinoma. Dermoscopy of vulvar LSA shows white-yellow structureless areas, comedo-like openings (yellow follicular plugs in hair-bearing skin), peripheral hyperpigmentation, sclerotic atrophic shiny background, and absent or attenuated normal mucosal pattern. Vessels are typically reduced, although chronic disease can show fine linear or arborizing vessels. Long-term high-potency topical steroid (clobetasol) maintenance reduces malignant transformation risk and is a cornerstone of management.

05Vulvar intraepithelial neoplasia (VIN) is divided into HPV-associated high-grade squamous intraepithelial lesion (HSIL, classic or usual VIN) and HPV-independent differentiated VIN. HPV-associated VIN is more common in younger women, often multifocal, and dermoscopically shows yellow to orange-yellow background with dotted, glomerular, or polymorphic vessels and a warty or pebbled surface. Differentiated VIN arises in long-standing LSA in older women, is unifocal, and shows pink to red structureless areas with subtle dotted or linear vessels and adjacent LSA features. Differentiated VIN carries higher rates of progression to invasive SCC than HPV-associated VIN.

06Vulvar SCC most often arises from differentiated VIN in LSA (older women) or from HPV-associated VIN (younger women, often multifocal). Dermoscopy shows red glistening structureless areas, ulceration, polymorphic atypical vessels, and a yellow-white scaly or warty background. Mohs and wide local excision with margin assessment remain standard surgical management. Cervical and vulvar HPV vaccination reduces HPV-associated VIN incidence in vaccinated cohorts.

07Extramammary Paget disease (EMPD) of the vulva is an uncommon intraepithelial adenocarcinoma typically presenting in postmenopausal women as a slowly enlarging erythematous, eczema-like, scaling or eroded plaque on the labia majora and inguinal folds. Dermoscopy shows a red glistening (milky-red) background, milky-red structureless areas, linear-irregular and dotted vessels, white halos around vessels, sometimes pseudonetwork, and erosion or scale. Underlying invasive adenocarcinoma is uncommon in primary EMPD but should be sought, especially in lesions persisting beyond simple eczema or fungal explanations. Workup includes evaluation for underlying GI, urinary, or breast malignancy when secondary EMPD is suspected. Management is wide local excision (or Mohs in selected cases), with imiquimod and photodynamic therapy as alternatives in non-surgical candidates.

08Bartholin gland cysts and tumors are usually palpated rather than dermatoscoped, but vestibular Bartholin tumors can ulcerate and present as unilateral red ulcerated nodules in the lower vestibule. Dermoscopy of malignant Bartholin tumors is nonspecific (red structureless areas, ulceration, polymorphic vessels). Any unilateral persistent Bartholin-area mass in a postmenopausal woman should be biopsied to rule out adenocarcinoma or other gland-derived malignancy, as primary Bartholin gland carcinomas are rare but clinically silent until late.

09Practical workflow: examine all pigmented and non-pigmented vulvar lesions with polarized dermoscopy at 10x or higher, document with photography given the medico-legal sensitivity, and biopsy any lesion with multicomponent disorganized pattern, multiple colors, atypical vessels, persistent ulceration, or growth. Follow LSA long-term with periodic clinical and dermoscopic review and a low threshold to biopsy any new firm, eroded, or warty area within an LSA field.