Low rates of clinical recurrence after biopsy of benign to moderately dysplastic melanocytic nevi

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.

Dysplastic nevus part II: Dysplastic nevi: Molecular/genetic profiles and management

Dermatologists frequently see patients with clinically atypical nevi and dermatopathologists interpret histologically dysplastic nevi on a near-daily basis, but there is great variability in the definition and management of such lesions. This part of the CME review focuses on information published since the previous comprehensive review (2012), with emphasis on molecular and genetic attributes of histologically dysplastic nevi and clinical management.

Dysplastic Nevi: Morphology and Molecular and the Controversies In-between

Dysplastic nevi are distinctive melanocytic lesions in the larger group of atypical nevi. They often are multiple and sporadic with genetic features intermediate between common acquired nevi and melanoma. Dysplastic nevi may be multiple, familial, and seen in patients with familial melanoma syndrome. Although their behavior is benign, they rarely represent a precursor to melanoma. If clinically suspicious, dysplastic nevi should be removed for adequate histopathologic examination and to exclude possibility of melanoma. Partial sampling should be avoided because reliable separation from melanoma requires visualization of the entire lesion to allow for examination of architectural histopathologic features and avoid sampling error.

Pathologists' agreement on treatment suggestions for melanocytic skin lesions

BACKGROUND

Although treatment guidelines exist for melanoma in situ and invasive melanoma, guidelines for other melanocytic skin lesions do not exist.

OBJECTIVE

To examine pathologists' treatment suggestions for a broad spectrum of melanocytic skin lesions and compare them with existing guidelines.

METHODS

Pathologists (N = 187) completed a survey and then provided diagnoses and treatment suggestions for 240 melanocytic skin lesions. Physician characteristics associated with treatment suggestions were evaluated with multivariable modeling.

RESULTS

Treatment suggestions were concordant with National Comprehensive Cancer Network guidelines for the majority of cases interpreted as melanoma in situ (73%) and invasive melanoma (86%). Greater variability of treatment suggestions was seen for other lesion types without existing treatment guidelines. Characteristics associated with provision of treatment suggestions discordant with National Comprehensive Cancer Network guidelines were low caseloads (invasive melanoma), lack of fellowship training or board certification (melanoma in situ), and more than 10 years of experience (invasive melanoma and melanoma in situ).

LIMITATIONS

Pathologists could not perform immunohistochemical staining or other diagnostic tests; only 1 glass side was provided per biopsy case.

CONCLUSIONS

Pathologists' treatment suggestions vary significantly for melanocytic lesions, with lower variability for lesion types with national guidelines. Results suggest the need for standardization of treatment guidelines for all melanocytic lesion types.

Assessment of Shave Removal Without Further Excision in the Treatment of Spitz Nevi: A Retrospective Study of 58 Cases

BACKGROUND

Spitz nevi (or tumors) are noncancerous growths that are found particularly in the pediatric population. Their histologic features overlap with melanoma, but they have a favorable prognosis, even when showing atypical features.

OBJECTIVES

The aim of this research is to examine whether Spitz nevi can be sufficiently removed by adequate shave excisions without a subsequent excision.

METHODS

Melan-A stained shave removal specimens (SRS) were obtained for 58 consecutively diagnosed Spitz nevi, along with slides of their postshave excision specimens. The SRS were reviewed for negative (clear) margins, defined as no neoplastic melanocytes detected within <0.2 mm of the deep and lateral margins of the specimen. Postshave excision specimens were reviewed for residual or recurrent lesions.

RESULTS

The 15 shave excision specimens with negative margins had no corresponding residual lesions on postshave specimens. There were no recurrences in any of the cases in an average of 17 months of follow-up.

CONCLUSIONS

Observation may be a logical approach for the management of Spitz nevi when shave removal achieves clear margins and the lesion lacks atypical features.

Risk of Subsequent Cutaneous Melanoma in Moderately Dysplastic Nevi Excisionally Biopsied but With Positive Histologic Margins

Importance

Little evidence exists to guide the management of moderately dysplastic nevi excisionally biopsied without residual clinical pigmentation but with positive histologic margins (hereafter referred to as moderately dysplastic nevi with positive histologic margins).

Objective

To determine outcomes and risk for the development of subsequent cutaneous melanoma (CM) from moderately dysplastic nevi with positive histologic margins observed for 3 years or more.

Design, Setting, and Participants

A multicenter (9 US academic dermatology sites) retrospective cohort study was conducted of patients 18 years or older with moderately dysplastic nevi with positive histologic margins and 3 years or more of follow-up data collected consecutively from January 1, 1990, to August 31, 2014. Records were reviewed for patient demographics, biopsy type, pathologic findings, and development of subsequent CM at the biopsy site or elsewhere on the body. The χ2 test, the Fisher exact test, and analysis of variance were used to assess univariate association for risk of subsequent CMs, in addition to multivariable logistic regression models. To confirm histologic grading, each site submitted 5 random representative slide cases for central dermatopathologic review. Statistical analysis was performed from October 1, 2017, to June 22, 2018.

Main Outcomes and Measures

Development of CM at a biopsy site or elsewhere on the body where there were moderately dysplastic nevi with positive histologic margins.

Results

A total of 467 moderately dysplastic nevi with positive histologic margins from 438 patients (193 women and 245 men; mean [SD] age, 46.7 [16.1] years) were evaluated. No cases developed into CM at biopsy sites, with a mean (SD) follow-up time of 6.9 (3.4) years. However, 100 patients (22.8%) developed a CM at a separate site. Results of multivariate analyses revealed that history of CM was significantly associated with the risk of development of subsequent CM at a separate site (odds ratio, 11.74; 95% CI, 5.71-24.15; P < .001), as were prior biopsied dysplastic nevi (odds ratio, 2.55; 95% CI, 1.23-5.28; P = .01). The results of a central dermatopathologic review revealed agreement in 35 of 40 cases (87.5%). Three of 40 cases (7.5%) were upgraded in degree of atypia; of these, 1 was interpreted as melanoma in situ. That patient remains without recurrence or evidence of CM after 5 years of follow-up.

Conclusions and Relevance

This study suggests that close observation with routine skin surveillance is a reasonable management approach for moderately dysplastic nevi with positive histologic margins. However, having 2 or more biopsied dysplastic nevi (with 1 that is a moderately dysplastic nevus) appears to be associated with increased risk for subsequent CM at a separate site.

Surgical re-excision vs. observation for histologically dysplastic naevi: a systematic review of associated clinical outcomes

BACKGROUND

The management of histologically dysplastic naevi (HDN) with re-excision vs. observation remains controversial because of lack of evidence about associated melanoma outcomes.

OBJECTIVES

To assess published data on the development of biopsy-site primary cutaneous melanoma among biopsy-proven HDN managed with either re-excision or observation.

METHODS

A systematic review of all published data: a total of 5293 records were screened, 18 articles were assessed in full text and 12 studies met inclusion criteria. No controlled trials were identified.

RESULTS

Most studies (11 of 12, 92%) were retrospective chart reviews, and one was both a cross-sectional and cohort study. Many studies (nine of 12, 75%) had no head-to-head comparison groups and either only reported HDN that were re-excised or observed. A total of 2673 (1535 observed vs. 1138 re-excised) HDN of various grades were included. Follow-up varied between 2 weeks and 30 years. Nine studies reported that no melanomas developed. Eleven biopsy-site melanomas developed across three of the studies, six among observed lesions (0·39%) and five among re-excised lesions (0·44%).

CONCLUSIONS

Based upon the available evidence the rates of biopsy-site primary melanoma were similarly low among observed lesions and re-excised lesions. This suggests that HDNs can be observed with minimal adverse melanoma-associated outcomes. However, all included articles were of low quality and further prospective trials could better guide clinical decision making.

The management of dysplastic naevi: a survey of Australian dermatologists

BACKGROUND/OBJECTIVES

The management of dysplastic naevi based on histopathological grading is a contentious issue. Comprehensive management guidelines are lacking and the approach taken varies between clinicians. The authors sought to understand how Australian dermatologists approach the management of biopsy-proven dysplastic naevi, and the impact of grading of dysplasia upon this management.

METHODS

In total, 547 Fellows of the Australasian College of Dermatologists were surveyed and 218 responses were collected (40% response rate).

RESULTS

Although all dermatologists surveyed would re-excise an incompletely removed severely dysplastic naevus, opinion was divided over whether to treat such a lesion as an in situ melanoma or a dysplastic naevus, with 55% of respondents using a 5-mm margin and the remainder opting for narrow margin re-excision. When the same lesion was reported to be clear of margins by 1 mm after biopsy and the clinical suspicion for melanoma was high, 44% would re-excise with a 5-mm margin.

CONCLUSIONS

The approach of Australian dermatologists to the management of dysplastic naevi varies between clinicians, reflecting the problems raised by the validity of histopathological grading.

Recurrence of Dysplastic Nevi Is Strongly Associated with Extension of the Lesions to the Lateral Margins and into the Deep Margins through the Hair Follicles in the Original Shave Removal Specimens

Melanocytic nevi, including dysplastic or atypical nevi (DN), can recur or persist following shave removal procedures, and recurrence may resemble melanoma, both clinically and histologically (pseudomelanoma). Recurrence may originate from proliferation of the remaining neoplastic melanocytes following incomplete removal. The present study determines the rate and etiology of this event. A cross-sectional analysis of 110 excision specimens showing histological recurrence was performed, and these specimens were compared to the slides of the original shave specimens showing mildly atypical DN. In the second portion of the study, a retrospective review of 167 cases with biopsy-proven mildly atypical DN which were followed up for at least two years was conducted to determine the rate of recurrence/persistence. When followed up for two years, DN, with positive shave margins, defined by extension or very close extension (≤0.2 mm) of the lesions to the lateral margins and into the deep margins through the hair follicles in the shave removal specimens, have a higher probability of recurrence than DN with negative (or clear) margins (odds ratio (OR) = 158; 95% confidence interval (CI) = 36.62–683; P < 0.001). The overall rate of histologically confirmed recurrence/persistence was approximately 10%.

Dysplastic (or Atypical) Nevi Showing Moderate or Severe Atypia With Clear Margins on the Shave Removal Specimens Are Most Likely Completely Excised

BACKGROUND

Dysplastic nevi (DN) are graded by their degree of atypia into 3 categories of mild, moderate, and severe. In many practices, DN with moderate or severe atypia are generally excised regardless of the status of the shave specimen margins.

OBJECTIVE

With a new approach toward the margins on the shave removal specimens (SRS), the goal herein is to assess whether the shave removal procedure can sufficiently remove DN with moderate or severe atypia.

METHODS

A total of 426 SRS diagnosed with DN showing moderate or severe atypia between January and December 2015 along with their post-shave excision specimens were reviewed. Based on the author's experience, clear or negative margins on the SRS were defined as neoplastic melanocytes confined within >0.2 mm of the lateral and deep specimen margins. The biopsy specimens were accompanied by Melan-A highlighting the subtle neoplastic cells.

RESULTS

With a negative predictive value (NPV) of 98.4% (confidence interval: 97.2% to 100%, P < .001), DN showing moderate or severe atypia with clear margins are most likely removed by the shave procedure.

CONCLUSION

Routine excision of DN showing moderate or severe atypia with clear margins on SRS is not necessary. Regular surveillance is sufficient.

The regenerating naevus

The re-emergence of a melanocytic proliferation at the site of a previously excised pigmented lesion may not only cause great concern clinically but may also be amongst the most difficult of all melanocytic lesions for pathologists to assess. These lesions can adopt an appearance which may be impossible to confidently distinguish from a regressing or traumatised melanoma on histological grounds alone. For this reason, careful attention must be paid to the clinical context which has given rise to the lesion or a misdiagnosis may occur. In the absence of a corroborating history of prior surgery or trauma to the site, a diagnosis of a regenerating naevus may only be provisional. When considering a diagnosis of regenerating naevus, whenever possible, it is important to review and confirm the benign nature of the precursor lesion. Nevertheless, 50 years of research into this phenomenon has identified certain characteristic clinical features and histological patterns which provide clues both to clinicians and pathologists that will assist them to make the correct diagnosis and avoid over diagnosing as melanoma what is ultimately a benign process.

Oral melanocytic nevi: a clinicopathologic study of 100 cases

OBJECTIVE

The purpose of this study was to evaluate the clinical and histopathologic features of oral melanocytic nevi (OMN).

STUDY DESIGN

One hundred cases of OMN were retrieved from the files of two oral pathology services, and the data were analyzed with regard to histologic type and clinical features.

RESULTS

Intramucosal nevus was the most common type (61%), followed by common blue nevus (23%), compound nevus (7%), and junctional nevus (3%). Combined nevus and cellular blue nevus were rare (2% each). The hard palate was the most commonly affected site (33%), followed by the buccal mucosa (18%), vermilion border of the lip (18%), and gingiva (15%). An interesting case of intramucosal nevus with lipomatosus-like changes and neurotization and two cases of oral dysplastic nevus are also reported.

CONCLUSIONS

Intramucosal and common blue nevi are the most common types of OMN. Dysplastic nevus, which is recognized as a marker for melanoma in the skin, can rarely involve the oral cavity. Accordingly, dentists, especially oral and maxillofacial pathologists, should become familiar with the clinical and histopathologic features of this entity.

Budget impact analysis of a novel gene expression assay for the diagnosis of malignant melanoma

BACKGROUND

Traditional pathology techniques alone can be insufficient to reliably distinguish between malignant melanoma, dysplastic nevi, and benign nevi in biopsies of suspicious pigmented lesions. Numerous studies have shown high rates of ambiguity when assessing such samples. A novel gene expression assay has been developed to objectively differentiate malignant melanoma from benign nevi.

OBJECTIVE

The purpose of this study was to quantify the economic impact of the gene expression assay on a US commercial health plan.

METHODS

The clinical paradigm of care was modeled for a hypothetical cohort of patients with suspicious pigmented lesions that are difficult-to-diagnose. Costs were assigned to each unit of care provided based on 2013 Medicare fee-for-service rates. Patients were followed for 10 years and were modeled to progress according to the natural history of their disease. The total cost of care was calculated for two scenarios: a Reference Scenario, representing current clinical practice, and a Test Scenario, in which each lesion was tested with the gene expression assay and diagnosed. Total cost of care was compared between the two scenarios to determine overall budget impact. Sensitivity analyses were performed to test the robustness of the model.

RESULTS

The gene expression assay reduces costs by $1268 per patient tested over 10 years, a decrease of 8.3%, after accounting for the cost of the assay. For a health plan with 10 million members, this would translate to over $8 million in savings. The largest portion of this saving comes from reducing the number of missed melanomas, which would otherwise progress to advanced disease. In sensitivity analyses, no single model input changed within a reasonable range of values caused the model to show that the assay was not cost-saving.

CONCLUSION

In addition to improving the diagnosis of melanoma, this gene expression assay would likely reduce costs for health plans that choose to cover it.

Outcomes of biopsies and excisions of dysplastic acral nevi: a study of 187 lesions

BACKGROUND

Despite their frequency in clinical practice, controversy exists regarding the significance and management of dysplastic nevi (DN). Although the perception of DN as precursors to melanoma is questionable, excisions of biopsy-proven DN are commonplace in clinical practice. The management of dysplastic acral nevi is of interest given the challenge of surgery at acral sites.

OBJECTIVE

To determine the outcomes of biopsies of clinically atypical acral nevi and excisions of histologically dysplastic acral nevi (HDN).

MATERIALS AND METHODS

Retrospective review of consecutive patients at a private dermatology practice who had a biopsy of an atypical acral nevus from December 2004 to July 2012.

RESULTS

One hundred eighty-seven atypical acral nevi were biopsied from 168 patients (77 (41%) HDN, 108 (58%) common nevi). Based on initial histology, 30 (39%) HDN were recommended for excision and eight (10%) for clinical observation. Twenty-seven of the 77 HDN were excised; 23 (85%) revealed scar only, and four (15%) revealed residual DN not involving the margin.

CONCLUSION

Routine excision of biopsy-proven dysplastic acral nevi may not be necessary.

Histologic outcomes of excised moderate and severe dysplastic nevi

BACKGROUND

Dysplastic nevi (DN) have been a matter of controversy since their initial description in 1978 because of differences in the clinical and histological terminology, and large studies on histological outcomes of excising moderate to severely DN have not previously been described.

OBJECTIVE

To determine the clinical characteristics of DN and histologic outcomes of excised moderate and severe DN.

METHODS

Retrospective chart review of patients with DN or Clark's nevi at the Dermatology Department at Rutgers-Robert Wood Johnson Medical School in Somerset, New Jersey, from January 2009 to June 2012. Three hundred ninety-three lesions from 380 patients were included in this study.

MAIN OUTCOME MEASURE

Histologic results of excised moderate and severe DN.

RESULTS

Thirty-four percent of DN were excised because of the presence of moderate or severe atypia, personal history of melanoma, or both. None of the excised lesions showed evidence of melanoma; 81.6% of excisions showed scar or granulation tissue. Only 14% of excised lesions were found to have residual lesions, and 4.4% showed recurrent nevi.

CONCLUSION

In 134 excisions of moderate to severe DN, no melanoma was identified. Most of the excisions showed scar or granulation tissue. The rate of residual lesions after shave biopsy of moderate or severe DN was lower than after punch biopsy.

Analysis of interobserver reproducibility in grading histological patterns of dysplastic nevi

BACKGROUND

Dysplastic nevi are among the most important cutaneous melanoma simulators. They are important risk markers for this neoplasia and can be its potential precursors. Some authors found a statistically significant relationship between the degree of dysplasia and the risk for developing melanoma. However, reproducibility of grading criteria ranged from poor to fair in the researched articles.

OBJECTIVE

To test the reproducibility of the grading criteria proposed by Sagebiel et al. regarding dysplastic nevi.

METHODS

Histological specimens of 75 dysplastic nevi were graded, independently and in a blinded fashion, according to preestablished criteria, by a panel of 10 pathologists with different levels of experience. Diagnostic agreement was calculated using weighted kappa and intraclass correlation coefficients.

RESULTS

The average of weighted kappa values was 0.13 for all observers, 0.12 for dermatopathologists, 0.18 for general pathologists and 0.05 for residents. Intraclass correlation coefficient values were 0.2 for all observers, 0.18 for dermatopathologists, 0.33 for general pathologists and 0.15 for residents.

CONCLUSIONS

Histopathological grading for dysplastic nevi was not reproducible in this Brazilian series, so the criteria used are not a helpful histopathological parameter for clinicopathological correlation.

Margin comments in dermatopathology reports on dysplastic nevi influence re-excision rates

BACKGROUND

Dermatopathology reports influence clinical management, but it is not clear to what extent comments on margin involvement of histopathologically dysplastic nevi (HDN) influence decisions about re-excision or complete excision.

OBJECTIVE

We sought to determine if standardized margin comments (MCs) on HDN influence re-excision rates.

METHODS

By reviewing medical records, we compared re-excision rates of HDN reported with (May 2011 to December 2012) and without (January 2007 to December 2010) standardized MCs, and surveyed clinicians to assess perceptions of the impact of MCs on their management of HDN.

RESULTS

Of 584 HDN, 302 had MCs and 282 did not. Re-excision was recommended or performed at a significantly higher rate for patients in the group without MCs (51.8%, 146 of 282) than in the MC group (39.4%, 119 of 302); P = .003 regardless of margin status. This difference was observed among HDN diagnosed as mildly and moderately dysplastic but not for severely dysplastic nevi. In all, 40% (16 of 40) of clinicians responded that they are more likely to biopsy pigmented lesions with a clinical margin of normal-appearing skin than they were before MCs were routinely included in dermatopathology reports.

LIMITATIONS

This was a retrospective study.

CONCLUSIONS

Re-excision rates were significantly lower in patients who had HDN reported with standardized MCs. MCs may help reduce re-excision rates, with associated reduction in health care use, cost, and morbidity.

The dysplastic nevus: from historical perspective to management in the modern era: part II. Molecular aspects and clinical management

The dysplastic nevus is a discreet histologic entity that exhibits some clinical and histologic features overlapping with common nevi and melanoma. These overlapping features present a therapeutic challenge, and with a lack of accepted guidelines, the management of dysplastic nevi remains a controversial subject. Although some differences between dysplastic and common nevi can be detected at the molecular level, there are currently no established markers to predict biologic behavior. In part II of this continuing medical education article, we will review the molecular aspects of dysplastic nevi and their therapeutic implications. Our goal is to provide the clinician with an up-to-date understanding of this entity to facilitate clinical management of patients with nevi that have histologic dysplasia.

Dysplastic nevi

Dysplastic nevi have been a subject of much debate since their original description in 1978. Although some question the biological potential of dysplastic nevi themselves, several studies have shown that their presence confers substantial risk for melanoma. In addition to predisposing patients to melanoma, dysplastic nevi have been shown to harbor genetic mutations, indicating their position on a continuum between banal nevi and melanomas. Dysplastic nevi are also clinically relevant as mimickers of melanoma, and can be challenging diagnostically. This article reviews the history, epidemiology, biology and genetics, clinical features, histopathologic features, and management guidelines for patients with these lesions.