Dermoscopic and Clinical Features of Pigmented Skin Lesions of the Genital Area (2024)

Abstract

Keywords: Dermoscopy, Melanosis, Nevus, pigmented

INTRODUCTION

Pigmented lesions of the genital region are uncommon. Its incidence accounts for10-12% of the population and for 20% of all vulvar diseases.¹ The most frequent locations forpigmented genital lesions are the vulva in women and the glans penis in men. In theliterature, there are only a few case reports about dermoscopic features ofpigmented genital lesions in male patients. Pigmented skin lesions in the genitalarea include nevi, melanoma, melanotic macules (lentiginosis, melanosis),angiokeratomas, seborrheic keratosis, squamous cell carcinoma, basal cell carcinoma(BCC).

Postmenopausal women are usually more affected by vulvar melanomas than premenopausalwomen. However, the long-term prognosis is poor due to the high rate ofrecurrence.^2-6 Atypical melanocytic nevi of thegenital type (AMNGT) and vulvar melanomas usually affect postmenopausal women andthe prognosis is poor due to the high recurrence.^2-6Histopathologically atypical melanocytic nevi of the genital type (AMNGT) showsimilar features to vulvar melanoma. ^7.8

Dermoscopy is a noninvasive tool that helps physicians distinguish melanomas fromother pigmented and non-pigmented skin lesions. It gives numerous clues about skinstructures in the epidermis, dermoepidermal junction, and dermis. Numerous methodshave been developed for the detection of lesion borders. Dermoscopic criteria havebeen described for the diagnosis of vulvar melanosis, and observational studies havebeen conducted to define the dermoscopic features of nevi and melanoma on thevulva.^9-12

It may be difficult to clinically and dermatoscopically distinguish between vulvarmelanoma and vulvar melanosis. ^11,13 To our knowledge, there have beenonly a few case reports about dermoscopic features of pigmented genital lesions inmale patients. ^14,15,16,17

In this study, we aimed to describe dermoscopic patterns of pigmented lesions in maleand female patients, according to the patient´s age, and anatomical location andhistological subtype of the lesion.

MATERIAL AND METHODS

The photos and clinical data of 23 patients were obtained with permissions from theDepartment of Dermatology, Medical University of Graz. The study protocol wasapproved by the local ethics committee. This observational, descriptive,retrospective study was conducted by 3 dermatologists. 68 patients with pigmentedgenital lesions were included in the study. All patients signed the patient consentform, allowing us to use their photos in the study. Inclusion criteria were: olderthan 18 years of age, consultation in the department of dermatology due to apigmented lesion of the genital area. For all participants, sex, age, anddermoscopic patterns, location, diameter and histological subtype of the lesion wererecorded. Location on the vulva was divided into 3 categories: labium major, labiumminor and cl*tor*s. Location on the penis was divided into 3 categories: glanspenis, meatus and shaft of the penis. Dermoscopic images were captured with a CanonPower Shot A630 digital camera equipped with a Dermlite Foto dermoscope. Solitarylesions were excised for histopathological examination and a 4 mm punch biopsy wasperformed in lesions larger than 10 mm. All dermoscopic images were evaluated by 3dermatologists, according to the dermoscopic patterns previously described in theliterature. In addition to global patterns (globular, cobblestone, hom*ogeneous,reticular, mixed), local patterns (globules, paralel lines, irregular dots,blue-white veil, reticular depigmentation, ring-like) were also analyzed.^{9,10,12,18-21} Based onthe dermatopathological diagnosis, the 68 pigmented lesions were then classified asvulvar melanosis, melanocytic nevus, atypical nevus and seborrheic keratosis.

SPSS 15.0 (SPSS Inc., Chicago, IL, U.S.A.) was used in the statistical analysis.Statistical significance was considered as p <0.05. Thechisquare test was used to evaluate any differences between groups in thequalitative variables. For correlations between variables, Spearman correlationcoefficients were estimated.

RESULTS

DISCUSSION

Pigmented skin lesions of the vulva are present in 12-19% of the women who have hadgynecological examination.⁹ Vulvarmelanosis is the most frequent lesion among these pigmented disorders.²² Vulvar melanosis usually occurs inwhite women and has an unknown etiology. Even though vulvar melanosis has a benignprognosis, it causes concern to the patient and to the physician, owing to itsmelanoma-like presentation.^11.13

Melanocytic nevi, whose dermoscopic features were first described by Rock B et al.,occur in approximately 2.3% of females.²² Atypical melanocytic nevi of the genital type (AMNGT) mayhistopathologically mimic malignant melanoma by the presence of atypical cells(melanocytes with larger, pleomorphic nuclei, sometimes with prominentnucleoli).

In this study, we evaluated only benign lesions of the genital area, includinggenital melanosis, atypical melanocytic nevi of the genital type (AMNGT),melanocytic nevi and seborrheic keratosis.

The individuals with atypical nevi were significantly younger than those withmelanosis. This result is consistent with those of previous studies.¹² In addition to the solitarypresence of most genital melanosis lesions, atypical and melanocytic nevi were alsopresent as solitary lesions. About one fourth of the lesions observed in this studywere atypical melanocytic nevi of the genital type (AMNGT), whose diagnosis wasconfirmed by histopathological examination. In our study, the number of AMNGT washigher than in previous studies. This result may be related to the highfemale-to-male ratio noticed in previous studies.^7,8,11 In our study, the female-to-maleratio was lower than the one found in previous studies. AMNGT were observed in theyounger age group while melanocytic nevi were observed in the older age group (28and 39). Our results support the findings by Ferrari et al. In the analysis ofdermoscopic features of 16 vulvar melanocytic nevi, Ronger-Savle et al showed thatthe hom*ogeneous and globular pattern is the most frequent dermoscopicpattern.¹² According tothe results from Ferrari et al., the globular pattern and the mixed pattern were themost common patterns in pigmented lesions of the vulva.¹¹ In our case series, most AMNGT had a mixed orglobular pattern. These data are similar to those reported by Ferrari andcolleagues.

The mixed pattern, which is created by parallel lines together with hom*ogeneouspigmentation or globules, is more commonly present in atypical nevi than inmelanosis and melanocytic nevi. Ferrari et al. suggested that a pigmented lesionmust be followed up or excised if it has a mixed pattern.¹¹ Our data supports this suggestion. Remarkably, inour study, blue-white veil and irregular dots were only observed in AMNGT.

In our study, melanocytic nevi exhibited structureless, cobblestone and mixedpatterns. Virgili et al showed that hom*ogeneous and globular patterns were commonlyseen in melanocytic nevi, in which a hom*ogeneous brown-gray pigmentation and shadesof brown, respectively, appeared.²³ These data are similar to those reported by Virgili andcolleagues. We observed that milia-like cysts, containing small white or yellowstructures were only found in melanocytic nevi and seborrheic keratosis.

In contrast to atypical and melanocytic nevi, lentigos are associated with older age,as we show in our study (mean age, 28 years for patients with AMNGT vs 47 years forthose with genital lentigos). It is reported that lentigos (melanosis) are the mostcommon pigmented lesions among women, present in approximately 7% offemales.^9,22 Vulvar melanoma is an uncommon tumor, with anincidence of 0.10/100.000 women annually and it accounts for 2-10% of all vulvarmalignancies.⁴ In theliterature, it was suggested that vulvar melanoma has a peak incidence after the 6thdecade.^2,3 Ferrari et al reported the disappearence of 2melanocytic nevi in two young girls in a 4-year dermoscopic follow-up. Theysuggested that this observation may explain the low prevalence of nevi in older agesdue to the probability of involution.

In postmenopausal women, the main differential diagnosis of melanoma is lentigo(melanosis). Vulvar melanosis may occur as multifocal macules with irregular shape,which usually show all the criteria of ABCD rules. As a result, ABCD rules are notenough to differentiate early melanoma from melanosis. Mannone et al observed thestructureless pattern, which is histopathologically characterized by moderate toevident hyperpigmentation along the basal cell layer as the most common pattern invulvar melanosis in their series.⁹In a larger case series, globular-like and parallel, reticular-like,cobblestone-like and ring-like patterns, and their relation with multifocality werealso described in melanosis.¹⁰ Inour study, the most typical pattern of melanosis in genital localization is the'parallel pattern'. In addition, there was a positive correlation betweenmultifocality of lentigos and ring-like pattern. This result is consistent withFerrari et al. ¹⁰

To date, 17 cases of vulvar melanoma have been reported in the literature.^11,19,23-27 In these cases, a multi-component pattern composedby blue-white veil, atypical network, irregular streaks, dots and atypical vesselswas exhibited. Ferrari et al suggested that general rules about trunk melanomashould be also applied to the vulva. According to the results of Ferrari et al andprevious series, none of the vulvar melanomas showed globular pattern. In addition,all the vulvar melanomas in their case series had 4 points or more when thealgorithm of Ronger- Savle et al was applied to the lesions.

It has also been reported that reticular depigmentation, a white network consistingof white, fragile lines, is a highly valuable dermoscopic finding in early vulvarmelanomas. ^11,28 This dermoscopic feature had been associated withmelanoma and Spitz nevi.^18,28 Reticular depigmentation was notobserved in our case series. Due to the benign histopathological results of ourcases, our data support previous findings.

Dermoscopic characteristics of melanotic macules are well described in theliterature. Uniform brown color (structureless or hom*ogeneous pattern), parallel(linear and curved streaks) pattern (the most common pattern in our study),ring-like pattern (multiple round to oval structures with well-defined regularborders) are the terms used to define mucosal melanosis by dermoscopy. In our study,we also observed globular and reticular patterns in melanosis lesions. Blue-whiteveil may be found in melanosis, even though this feature is more common in melanoma.^9,10 As a result, vulvar pigmented lesionsdermoscopically exhibiting blue-white veil should be excised or biopsed to rule outmelanoma.

The limitation in our study were the low sample size and the inclusion of only benignlesions. The parallel pattern was the most frequent pattern in melanosis.Additionally, ring-like pattern was only observed in melanosis. Lesions had 2 ormore standardized dermoscopic colours in females. The ringlike pattern was morecommon in males than females. Most pigmented lesions on the genital area weresolitary lesions. Blue-white veil and irregular dots were only observed in AMNGTlesions. Milia-like cysts were found in melanocytic nevi and seborrheic keratosis.Even if there is currently no available information whether vulvar melanoma arisefrom AMNGT or not, it is better to remove lesions. Clues for AMNGT are given bydermoscopy.

CONCLUSION

In the literature, there are data on dermoscopic and clinical features of vulvarlesions. To our knowledge, our study is the first study that evaluated dermoscopicand clinical characteristics of both female and male patients. We aimed to determinespecific dermoscopic features of AMNGT and lesions which must be followed-up. It maybe difficult to distinguish between benign and malign lesions by dermoscopy, hence,all suspicious lesions must be removed. Further prospective studies of a largernumber of patients and genital pigmented lesions will give more definiteresults.

Footnotes

References