Nevi of Special Sites

A Single-Institution Cohort Study With Nevi of Special Site: Recurrence, Progression to Melanoma, and Patterns of Management

ABSTRACT

Nevi of specialized sites (NOSS) occur on the scalp, ears, flexural, acral, and genital areas and display atypical clinical and histologic features. We assessed NOSS recurrence and progression to melanoma, management patterns, and associations between histologic features and treatment recommendations. We queried all histologic diagnoses of NOSS (n = 275) from 2012 to 2017 from a large U.S. academic medical center with reference dermatopathology laboratory and matched these to clinical records. A blinded panel of dermatopathologists re-evaluated lesions, catalogued histologic findings, and gave management recommendation. Associations with dermatopathologist decision and concordance between new and original recommendations were assessed. Of 117 cases with follow-up, 2 locally recurred (1.46%) and none eventuated in melanoma. Clinical features were not associated with original treatment recommendations. After histopathologic review, large melanocytes [odds ratio ratio (ORR) = 8.00, 95% CI, 1.35-47.4] and junctional mitotic figures (ORR = 65.0, 6.5-650) predicted excision recommendation. Likewise, accumulation of many (>9) high-risk features was associated with excision recommendation. Panel review changed treatment recommendation in 27% of cases. Fair concordance existed between original and panel recommendations (κ = 0.29, 0.15-0.44). The low rate of recurrence and lack of melanoma occurrence suggest that despite an atypical clinical and histopathologic appearance, these nevi have limited potential for malignant transformation. Histopathologic findings seem to be principal drivers behind the recommendation for excision in this analysis. Variability existed in treatment recommendations; the panel's consensus recommendation tended to downgrade treatment. This highlights the importance of further outcomes-based studies to identify true high-risk features and refine management guidelines.

A Scoping Review and Population Study Regarding Prevalence and Histopathology of Juvenile Vulvar Melanocytic Lesions. A Recommendation

Cases of vulvar melanocytic lesions in juveniles are rarely reported. We analyze the evidence regarding vulvar melanocytic lesions in juveniles with or without vulvar lichen sclerosus to help decision making by clinicians and pathologists. A scoping review on vulvar melanocytic lesions with or without vulvar lichen sclerosus, including malignant vulvar melanomas, in females up to age 18 years was performed. In addition, the histopathology records of the cohort of all such lesions in The Netherlands from 1991 through 2020 were investigated, and a structured analysis of tissue samples of the subset of cases with lichen sclerosus was performed. The literature study performed confirms that vulvar melanomas in juveniles are extremely rare and that published case reports are often disputed. In The Netherlands, there are no cases of malignant vulvar melanomas up to age 18 years recorded from 1991 through 2020. Atypical histopathological features are often found in biopsies of vulvar nevi in juveniles, especially with concomitant lichen sclerosus, confirming earlier case studies in the literature. We conclude that even with atypical findings, vulvar melanocytic lesions in juveniles have a benign course. To avoid unnecessary and possibly mutilating procedures, we advise referral to an expert center and adaption of existing guidelines for vulvar melanocytic lesions in juveniles.

Melanocytic Nevi with Site-related Atypia: A Case Series and Characterization of their Immunohistochemical Profile

BACKGROUND

Nevi of special sites (NOSS) are benign melanocytic lesions that occur at particular sites. Although the histological features of NOSS have been described, their immunophenotypic features have not been fully characterized.

AIMS

To present the clinicopathological characteristics of a case series of NOSS and to characterize their immunohistochemical profile.

MATERIALS AND METHODS

Thirty-five NOSS were assessed using immunoperoxidase staining techniques for the melanocytic (S100, Melan-A, and HMB45) and proliferation (Ki-67) markers RESULTS: All of the cases of NOSS showed concerning architectural changes (prominent lentiginous melanocytic proliferation, irregularities, crowdedness, and dyhesiveness of the nests), and cytological atypia (large nevomelanocytes with vesicular nuclei, clear cytoplasm, and dusty melanin pigment) that can lead to a misdiagnosis of atypical nevi or even melanomas. All of the cases of NOSS showed diffuse expression of S100 and Melan-A proteins. Ki-67 labeling index of the nevomelanocytes was extremely low. HMB45 protein expression was limited to the junctional and superficial dermal nevomelanocytes.

CONCLUSIONS

NOSS can show histological features that can easily mimic atypical nevi or melanomas and this diagnostic consideration should be kept in mind to avoid their misdiagnosis. The expression of HMB45 protein in NOSS indicates that their nevomelanocytic cells have an activated phenotype. The decreased HMB45 protein expression following a gradient from junctional to deeper dermal localization in NOSS is indicative of their immunohistochemical maturation.

Dermoscopic characteristics of acral melanocytic nevi in children and adolescents

BACKGROUND/OBJECTIVE

There are limited data on the dermoscopic characteristics of acral nevi in the population under 18 years old. Our aim was to determine the frequency of acral volar nevi in children and adolescents, characterize their dermoscopic patterns, and identify relationships with age and location.

METHODS

We prospectively examined the palms and soles of 1319 patients presenting to our outpatient clinic from July 2018 to April 2019.

RESULTS

Acral volar nevi were observed in 28% of the children and adolescent population included in the study. A total of 474 nevi from 365 patients were examined. The presence of nevi increased with age. The most common dermoscopic pattern was parallel pigmented furrows, detected in 57.8% of nevi. The other patterns observed were combination (14.1%), fibrillar (10.1%), and latticelike (8.8%). The parallel furrow and globulostreak-like patterns were more common on the palms, whereas the fibrillar and combination patterns were more frequently seen on the plantar surfaces. While the frequency of the parallel pigmented furrow pattern did not differ between the 0- to 12-year and 13- to 18-year age-groups, the dotted variants of the parallel furrow were observed more frequently in the 0- to 12-year-olds (58.2%) than in the 13- to 18-year-olds (41.7%). A combination pattern and its most common variant, parallel furrow + crista dotted pattern, were detected at a significantly higher rate in the 0- to 12-year group (22.1% and 16.3%, respectively) compared to the 13- to 18-year group (11.4% and 6%, respectively).

CONCLUSIONS

Acral melanocytic nevi are common in children and adolescents, and their dermoscopic patterns may be associated with anatomic localization and age.

Juvenile melanocytic acral nevus: A comparative study between MANIAC and non-MANIAC nevus and its clinicopathological characteristics

BACKGROUND

Melanocytic acral nevi have a series of distinguishing features, including their location, patient age at onset, clinical progression, and histological findings. In particular, histopathological analysis often reveals a melanocytic acral nevus with intraepidermal ascent of cells (MANIAC nevus), which in some cases can be mistaken for atypia or malignancy.

AIM

This study describes the clinicopathological characteristics of acral nevi in patients under 18 years old and contrasts the clinical and histological features between MANIAC vs non-MANIAC nevi.

METHODS

This was a retrospective observational study, performed in our department in the decade between January 2007 and January 2017. We included patients younger than 18 years of age who were subjected to the removal of melanocytic acral nevi.

RESULTS

A total of 70 patients were studied. 54.2% (38/70) were females and 45.8% (32/70) were males. With regard to the type of nevus, 34 were compound, 27 were junctional, and 9 were predominantly intradermal lesions. We identified a total of 41 MANIAC nevi and 29 non-MANIAC nevi. Statistically significant differences between these two groups were identified in nevus size (larger in MANIAC) and the frequency of compound nevi (higher in the MANIAC group), but not in the remainder of the histological parameters studied.

Primary Cutaneous Umbilical Melanoma: The Michigan Experience

BACKGROUND

Primary cutaneous umbilical melanoma is rare. Thorough information regarding its characteristics and treatment, including use of sentinel lymph node biopsy (SLNB) staging, is difficult to obtain. The unique anatomy of the umbilicus adds to the complexity of diagnosing and treating melanoma at this site.

OBJECTIVE

To improve understanding of diagnosis and treatment of primary cutaneous umbilical melanoma through presenting 7 new cases and reviewing 39 cases in the literature.

MATERIALS AND METHODS

The University of Michigan melanoma database query and review of the literature regarding reported cases of primary umbilical melanoma.

RESULTS

In 7 new and 39 previously reported cases of primary cutaneous umbilical melanoma, we describe signs and symptoms, histopathologic features, differential diagnosis, relevant anatomical considerations, and definitive treatment including SLNB when applicable.

CONCLUSION

Our series, combined with a thorough literature review and compilation of findings, provides a better understanding and appreciation of melanoma in the unique anatomical site of the umbilicus, with a reminder to carefully examine the umbilicus during a full skin examination in patients at risk of melanoma. Primary umbilical melanoma presents and can be appropriately treated similarly to cutaneous melanoma in other sites, with attention to relevant anatomy.

Total Body Skin Examination Practices: A Survey Study Amongst Dermatologists at High-Risk Skin Cancer Clinics

Background/Objectives

Although total body skin examination (TBSE) is the primary screening mechanism for melanoma, there is no consensus on which anatomic sites a screening TBSE should include. We sought to establish which anatomic sites are examined during routine (>90%) TBSEs of patients at high risk for skin cancer.

Methods

A Google survey was emailed to 173 international dermatologist skin cancer specialists.

Results

More than 75% of participants reported routinely examining the scalp, ears, face and neck, trunk, breasts, inframammary areas, axillae, extremities, palms and soles, nails, interdigital spaces, and buttocks. The least frequently inspected anatomic sites included genitalia, with male genitalia more frequently examined than female (penis n = 39; 52%; labia majora n = 21; 28%; P = 0.003), the perianal region (n = 26; 34.7%), and the ocular conjunctiva and oral mucosa (n = 35; 46.7%). Participants cited not screening these areas because of perceived patient discomfort, low prevalence of malignancy, and the expectation that other specialists examine the area.

Conclusions

The role of routine surveillance of neglected anatomic sites is unclear and warrants further discussion weighing potential mortality benefit against the incidence of melanoma in obscure sites, morbidity of intervention in sensitive sites, cost-effectiveness, and potential for patient discomfort.

Hyalinized Neurofibromas: Not Just Rare Variants in Skin of the Female Breast

Although classical neurofibromas are commonly encountered skin lesions, histologic variants are infrequent. We report a greater than 15-year retrospective review of a single institution's experience with the histopathologic diagnosis of neurofibroma of the female breast with a focus on the hyalinized variant. An electronic histopathology record review (CoPathPlus; Cerner Corp, North Kansas City, MO) was conducted from January 1, 2000, to October 16, 2015, for all "neurofibroma" diagnoses rendered in "females" at the anatomical site "breast". All cases were microscopically revisited and subclassified into 1 of 10 histopathologic categories. Immunohistochemistry (IHC) for S100, tryptase, and CD117 were performed on 19 hyalinized and 19 age-matched classical neurofibromas. During the study period, 62,021 breast specimens were reviewed at our institution. Of these, 86 (0.14%) were diagnosed as neurofibromas. Subclassification was as follows: 50 classical (58%), 19 hyalinized (22%), 6 diffuse (7%), 5 cellular (6%), 3 myxoid (4%), 2 epithelioid (2%), and 1 plexiform (1%). All hyalinized and age-matched classical neurofibromas were S100 positive. The mean number of IHC-positive mast cells per high-power field (hpf) was 34.5 by tryptase and 26.8 by CD117 for the hyalinized subset and 22.5 by tryptase and 19.3 by CD117 for the classical cohort. Published literature reports a 2.6% incidence of hyalinized neurofibromas at nonspecial cutaneous sites. Our series details a 22% incidence in the breast. Regarding pathophysiology, there is a statistically significant increase in the average number of IHC-positive mast cells per hpf in hyalinized variants when compared with classical neurofibromas of the breast both by tryptase (P = 0.00157) and CD117 (P = 0.00901).

DERMOSCOPY OF THE MONTH Nevi with Site-Related Atypia

The term “nevi of special sites” refers to melanocytic nevi of specific anatomic locations including the breast, axillae, umbilicus, genitalia, flexural areas, acral surfaces, ear, scalp and the conjunctiva. Nevi from these anatomic sites display sometimes dermoscopic and histological features of melanoma, resulting in unnecessarily high rates of excisions and re-excisions. Some authors have categorized nevi excised in the axillary, breast, umbilical and perineal areas as the nevi of the milk line. Two patients, a 32-year-old female and 23-year-old male with breast and periumbilical pigmented lesions, presented to our Department during 2017. Dermoscopy revealed features that were highly specific for melanoma. Excisional biopsies were done and histopathology revealed benign nevi with present site-related atypia. Irregular blotches, non-uniform radial streaks, blue-gray veil, and regression are the most specific features of melanoma of the breast and flexural areas. Excision is always recommended in pigmented lesions on the breast and flexural areas, which exhibit these features. However, larger studies are needed to define specific criteria required to distinguish special-site nevi from melanoma.

Dermoscopic and confocal features of an axillary "special site" nevus

“Nevi of special sites” is a term that denotes melanocytic nevi presenting in specific anatomic locations including the scalp, genital area, flexural sites, and acral sites [1]. Nevi from these anatomic sites display at times histopathologic features that may lead the reading pathologist to recommend re-excision of these benign nevi. Reflectance confocal microscopy (RCM) is a noninvasive imaging tool that allows for visualization of epidermal, dermal-epidermal junctional (DEJ), and superficial dermal tissue structures at cellular level resolution. RCM features of special site nevi have not been previously described in the literature. Defining the RCM characteristics of special site nevi may increase diagnostic accuracy and assist in ruling out melanoma.

Here, we report a case of a pigmented lesion appearing in the axilla of a patient with a recently diagnosed melanoma. Dermoscopic and histopathologic results were consistent with the diagnosis of nevus in flexural anatomic sites. In this case, RCM showed a regular honeycomb pattern of epidermal keratinocytes and enlarged, non-homogenous, discohesive nests at the DEJ, a pattern that corresponded well with the histopathologic findings. Larger studies are needed to establish RCM features of special site nevi in order to reliably rule out melanoma and lower the rate of unnecessary excisions of these benign nevi.

Reasons for rarity of anal melanocytic naevi

In the last 16 years only seven definite cases of anal melanocytic naevi have been reported in the literature. We describe three new cases, none of which were suspected clinically and were incidentally diagnosed on histological examination of haemorrhoidectomy specimens. The infrequency of these special site flexural melanocytic lesions may be related to changes in the involutionary mechanisms of the anal melanocyte proliferation. However, other factors related to the low detection rates by clinicians and pathologists need also to be considered.

Selected benign cutaneous lesions that may simulate melanoma histologically

As cutaneous melanomas manifest a wide spectrum of clinical and pathologic presentations, several other lesions enter into their differential diagnosis. This article considers those entities, including melanocytic hyperplasia, cellular nodules in congenital nevi, atypical lentiginous melanocytic proliferations, "special site" nevi, epithelioid histiocytoma, neurothekeoma, cellular schwannoma, and proliferating scars.

Umbilical and periumbilical dermatoses

The umbilicus may be the site of congenital and acquired malformations and may harbor clinical clues to the diagnosis of potentially fatal inherited disorders, primary skin conditions, and a variety of infectious diseases. Both benign and malignant tumors may involve the umbilicus, and some are unique to this site. Finally, cutaneous signs localized to this anatomic location may be found in diverse systemic diseases.

Lesions of the umbilicus: what the minimally invasive gynecologic surgeon needs to know about the belly button

The umbilicus is viewed as a portal by the laparoscopic surgeon, a doorway to the real business at hand. However, the umbilicus itself may be the site of a variety of lesional conditions. Some of these may be iatrogenic, caused by prior surgical interventions, such as endometriosis or seeding of a malignant neoplasm. Some may be the initial presenting complaint. This review discusses umbilical lesions that may be encountered by the minimally invasive gynecologic surgeon.