Atypical mole syndrome

Differences in nomenclature usage and preference among dermatopathologists for "dysplastic" nevi: A national survey

BACKGROUND

Ongoing controversy exists regarding terminology used to describe atypical melanocytic nevi. Efforts to standardize nomenclature, including the 1992 NIH consensus conference, have been largely unsuccessful. Significant advances have revealed an increasingly detailed genetic picture of melanocytic neoplasms, including strong evidence for the existence of those with "intermediate" behavior.

METHODS

We sent an electronic survey to dermatopathologists (n = 846) to assess trends in nomenclature usage and attitudes toward developing new consensus nomenclature for atypical melanocytic nevi.

RESULTS

There were 229 complete responses (27.1% response rate). The most used/preferred nomenclature was "dysplastic nevus" (43%/39%, respectively), followed by the NIH-recommended terminology (28%/26%). Three-tier grading systems were most heavily used/preferred (79%/63%). Dermatopathologists based in New England were most likely to use the NIH terminology; on the other hand, "dysplastic nevus" or "other" were most used elsewhere (p = 0.029). Most (76%) expressed at least "moderate" enthusiasm for developing consensus nomenclature, with 47% "very" or "extremely" enthusiastic.

CONCLUSION

Little has changed with the wide variation in terminology for atypical melanocytic nevi. There continues to be no one dominant terminology in use. However, there is enthusiasm for standardization. A new attempt at updated consensus nomenclature may be fruitful.

Melanocytic Nevi in Malignant Melanomas

Background:

A substantial proportion of malignant melanomas arise in preexisting melanocytic nevi. However, the clinical and dermoscopic features of such combination lesions have not been well defined in the literature.

Objective:

To determine the ability to recognize in thin malignant melanomas the presence or absence of melanocytic nevi based on clinical and/or dermoscopic observations.

Methods:

Thirty malignant melanomas, less than 1 mm in Breslow thickness, were studied clinically, dermoscopically, and histologically for the presence or absence of features of a melanocytic nevus.

Results:

The ability to recognize melanocytic nevi within thin malignant melanomas was poor by clinical and dermoscopic examinations, with 30% false negatives and 23% false positives.

Conclusion:

One cannot depend on clinical and/or dermoscopic observations to rule out a melanocytic nevus within a thin malignant melanoma. Histopathologic study of a small portion of a combined melanocytic neoplasm could lead to the mistaken conclusion that the lesion is entirely a melanocytic nevus or entirely a malignant melanoma. Therefore, when feasible, lesions suspected of being malignant melanomas should be totally excised and step-sectioned throughout.

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.

Agreement of dermatopathologists in the evaluation of clinically difficult melanocytic lesions: how golden is the 'gold standard'?

BACKGROUND

The 'gold standard' for the diagnosis of melanocytic lesions is dermatopathology. Although most of the diagnostic criteria are clearly defined, the interpretation of histopathology slides may be subject to interobserver variability.

OBJECTIVES

The aim of this study was to determine the variability among dermatopathologists in the interpretation of clinically difficult melanocytic lesions.

METHODS

This study used the database of MelaFind®, a computer-vision system for the diagnosis of melanoma. All lesions were surgically removed and sent for independent evaluation by four dermatopathologists. Agreement was calculated using kappa statistics.

RESULTS

A total of 1,249 pigmented melanocytic lesions were included. There was a substantial agreement among expert dermatopathologists: two-category kappa was 0.80 (melanoma vs. non-melanoma) and three-category kappa was 0.62 (malignant vs. borderline vs. benign melanocytic lesions). The agreement was significantly greater for patients ≥40 years (three-category kappa = 0.67) than for younger patients (kappa = 0.49). In addition, the agreement was significantly lower for patients with atypical mole syndrome (AMS) (kappa = 0.31) than for patients without AMS (kappa = 0.76).

LIMITATIONS

The data were limited by the inclusion/exclusion criteria of the MelaFind® study. This might represent a selection bias. The agreement was evaluated using kappa statistics. This is a standard method for evaluating agreement among pathologists, but might be considered controversial by some statisticians.

CONCLUSIONS

Expert dermatopathologists have a high level of agreement when diagnosing clinically difficult melanocytic lesions. However, even among expert dermatopathologists, the current 'gold standard' is not perfect. Our results indicate that lesions from younger patients and patients with AMS may be more problematic for the dermatopathologists, suggesting that improved diagnostic criteria are needed for such patients.

Atypical mole syndrome and dysplastic nevi: identification of populations at risk for developing melanoma - review article

Atypical Mole Syndrome is the most important phenotypic risk factor for developing cutaneous melanoma, a malignancy that accounts for about 80% of deaths from skin cancer. Because the diagnosis of melanoma at an early stage is of great prognostic relevance, the identification of Atypical Mole Syndrome carriers is essential, as well as the creation of recommended preventative measures that must be taken by these patients.

Selection criteria for genetic assessment of patients with familial melanoma

Approximately 5% to 10% of melanoma may be hereditary in nature, and about 2% of melanoma can be specifically attributed to pathogenic germline mutations in cyclin-dependent kinase inhibitor 2A (CDKN2A). To appropriately identify the small proportion of patients who benefit most from referral to a genetics specialist for consideration of genetic testing for CDKN2A, we have reviewed available published studies of CDKN2A mutation analysis in cohorts with invasive, cutaneous melanoma and found variability in the rate of CDKN2A mutations based on geography, ethnicity, and the type of study and eligibility criteria used. Except in regions of high melanoma incidence, such as Australia, we found higher rates of CDKN2A positivity in individuals with 3 or more primary invasive melanomas and/or families with at least one invasive melanoma and two or more other diagnoses of invasive melanoma and/or pancreatic cancer among first- or second-degree relatives on the same side of the family. The work summarized in this review should help identify individuals who are appropriate candidates for referral for genetic consultation and possible testing.

Cutaneous melanoma: family screening and genetic testing

The incidence of cutaneous melanoma (CM) has been steadily increasing in recent decades. Ultraviolet radiation (UVR) exposure, in the form of intermittent heavy exposure and severe sunburns in childhood, is believed to be the most important environmental contribution to CM risk. Genetic determinants also modulate CM risk, probably to a greater extent than environmental exposure. Certain heritable traits such as prominent numbers of common and atypical melanocytic nevi, skin type, dense UVR-induced freckling, and hair color are all known to be associated with increased CM risk. Very rarely, a heritable mutation in a high-risk gene renders the susceptible individual at extreme risk for CM. Families may carry one or more of the other high-risk phenotypic traits leading to uncertainty about how to quantify CM risk and provide management recommendations. Commercial genetic testing for the known high-risk inherited genetic mutations is available but is only relevant for those rare families likely to be carrying identifiable mutations. CM screening and risk intervention programs are being established internationally for families at markedly increased risk. Algorithms based on the level of risk are proposed.

Evaluation of germline CDKN2A, ARF, CDK4, PTEN, and BRAF alterations in atypical mole syndrome

Atypical mole syndrome is a sporadic or an inherited condition with an increased risk of melanoma. Germline mutations in the CDKN2A, ARF, CDK4 and somatic mutations in the PTEN and BRAF genes have been associated with melanoma. In this study, we evaluated genes associated with familial and sporadic melanoma for mutations in 28 probands with the atypical mole syndrome. No sequence alterations in the coding regions or in the splice junctions of CDKN2A, ARF, CDK4, PTEN or BRAF were identified. These data suggest that genes evaluated in this study are unlikely to be candidate genes for atypical mole syndrome and support the notion that unknown susceptibility gene/s for this disease exist.

Detection of melanomas in patients followed up with total cutaneous examinations, total cutaneous photography, and dermoscopy

BACKGROUND

Many factors have been identified as important determinants that increase the risk of malignant melanoma (MM) developing. Patients with classic atypical mole syndrome (CAMS) have multiple such factors and are known to be at high risk for MMs developing.

OBJECTIVE

We sought to evaluate the risk for newly diagnosed MMs developing in patients with CAMS and in a heterogeneous group of patients at high risk (ie, those with high-risk non-CAMS [HRNCAMS]) who had 1 or more risk factors: personal history of nonmelanoma skin cancers; family history of melanoma; biopsy specimen-confirmed dysplastic nevi; and meeting 1 or 2 of the 3 CAMS criteria. We also aimed to report our experience treating these patients at high risk with annual total cutaneous examination, total cutaneous photography, and dermoscopy.

METHODS

Consecutive medical records from a private dermatology practice were reviewed. A total of 258 patients were selected who fulfilled the criteria of having: (1) total cutaneous photography as an aid for follow-up; (2) total cutaneous examination at least once per year; (3) at least 6 months of clinical follow-up; and (4) no personal history of melanomas. A total of 160 patients with CAMS and 98 with HRNCAMS were included in this study. The 10-year risk for MM developing in these 2 cohorts was computed using the Kaplan-Meier method.

RESULTS

In the CAMS cohort, 28 new MMs developed in 19 patients resulting in a cumulative 10-year risk of 14% (95% confidence interval: 7-20). In the HRNCAMS cohort, 10 new MMs developed in 9 patients, and the cumulative 10-year risk was 10% (95% confidence interval: 2-17). The difference between the 2 groups was not statistically significant (P=.91). The MMs diagnosed in both cohorts were either in situ or less than 1 mm in Breslow thickness. There were no MM metastases or MM-related deaths in either cohort during a mean follow-up period of 120 months for the CAMS and 98 months for the HRNCAMS group.

CONCLUSION

Both the patients with CAMS and HRNCAMS were at very high risk for MMs developing. The combination of total cutaneous photography, total cutaneous examination, and dermoscopy were used in treating our patients. No MM 1 mm or greater in thickness developed during follow-up in either group.

Acquired melanocytic nevi as risk factor for melanoma development. A comprehensive review of epidemiological data

Acquired melanocytic nevi (MN) in Caucasian populations are important markers for the risk of melanoma development. The total number of MN on the whole body is the most important independent risk factor for melanoma and the risk of melanoma development increases almost linearly with rising numbers of MN. Additionally, the presence of atypical MN and of actinic lentigines are likewise independent risk factors for melanoma. Atypical mole syndrome should be defined by the presence of many acquired MN and a threshold number of atypical MN. Acquired MN develops mainly during childhood and adolescence in the first two decades of life. The number of acquired nevi seems to be related to hereditary factors and nevus-prone families exist. The amount of sun exposure is the most important environmental risk factor for nevus development, particularly in early childhood. Interestingly, sunburns may play a role in nevus development, but seem not to be required, and even moderate sun exposure promotes the process. Therefore, preventive measures for nevus and melanoma development should target young children and adolescents.

Tumor progression, early diagnosis and prognosis of melanoma

Primary melanomas evolve from melanocytes or from precursor lesions through two stages: the radial and vertical growth phases. The radial growth phase may be in situ or microinvasive, but is a non-tumorigenic neoplastic process, while the vertical growth phase is tumorigenic. The prognosis in radial growth phase is excellent irrespective of thickness or other variables. Curable radial growth phase melanomas can be recognized by surveillance of patients identified by screening for risk markers which include dysplastic nevi, common nevi, freckles, and other indicators of chronic or acute sun exposure or sun sensitivity. The prognosis in vertical growth phase depends on attributes of the tumor and of the host. The tumor mitotic rate, the presence of host tumor-infiltrating lymphocytes (TIL) within the vertical growth phase, and tumor thickness are the most powerful predictors of survival. New prognostic attributes are needed not only to provide for more accurate prognosis and diagnosis, but also to test the relevance of in vitro or animal studies in a human neoplastic system. Such attributes will be developed in the future based on markers that are associated with tumor progression. Candidate markers include growth factors and cytokines and their receptors, adhesion molecules and their ligands, chemotactic and motility factors, immune response-related molecules, and tumor-associated proteases. Some of these markers that are represented in the transition from radial to vertical growth phase will be reviewed. The tumor progression model presented here has been of value in the development of more accurate prognostic models, and in the elucidation of mechanisms of the malignant phenotype in melanoma.

Dysplastic changes in different types of melanocytic nevi. A unifying concept

We observed histopathologic changes previously described in dysplastic melanocytic nevi in association with a dermal component characteristic of other types of melanocytic nevi or overlapping with features of other varieties of nevi. In order to determine the frequency of these changes, we studied 2,164 cases of compound melanocytic nevi that fulfilled the histopathologic criteria for the diagnosis of compound dysplastic nevus, including architectural pattern, cytologic features, and mesenchymal changes. Of the 2,164 compound dysplastic melanocytic nevi, 1,895 (87.6%) had the histopathologic characteristics previously described for dysplastic nevus, 179 (8.3%) showed a dermal component with a congenital pattern, 67 (3.1%) demonstrated epidermal and dermal characteristics of Spitz's nevus, 8 (0.3%) had features of a combined blue nevus, 13 (0.6%) had a halo phenomenon and 2 (0.1%) showed dermal neuronevus. By considering these nevi as variants of dysplastic nevi, one may apply a unified conceptual basis for their nomenclature. In order to completely describe the appearance of the nevus, we named them by adding the term "dysplastic", to their main histopathologic subtype. Accordingly, six different varieties of dysplastic nevi were identified: 1) dysplastic nevus (original); 2) dysplastic nevus with a congenital pattern; 3) dysplastic Spitz's nevus; 4) dysplastic combined blue nevus; 5) dysplastic halo nevus; and 6) dysplastic neuronevus. In summary, we conclude that the histopathologic criteria previously reported for the diagnosis of dysplastic nevi may be found in association with a dermal component characteristic of other types of melanocytic nevi or may have overlapping features with other variants of nevi.

Skin cancer screening

The key to reducing morbidity and mortality from skin cancer is early detection. Prevention through education is, of course, ultimately the best outcome of collective human efforts. Many questions are still unresolved, but skin cancer screening by general internists, family practitioners, dermatologists, and other health professionals could prove cost-effective and reliable. As more knowledge becomes available, clinicians will have the resources to improve skills in prevention and early detection.

Case-control study of melanocytic nevi on the buttocks in atypical mole syndrome: role of solar radiation in the pathogenesis of atypical moles

BACKGROUND

It is not known why melanocytic nevi (MN) become dysmorphic (atypical) in patients with the atypical mole syndrome (AMS). A complex origin for acquired MN has been postulated. Genetic predisposition, solar radiation, and/or the formation of a sun-induced circulating mitogenic factor may contribute to the formation of MN.

OBJECTIVE

This study was undertaken to help elucidate the pathogenesis of atypical MN in patients with AMS.

METHODS

The number of common and atypical MN was determined for a defined sun-protected area on the buttocks in 150 patients with AMS (cases) and 150 control subjects without AMS. Patients and control subjects were matched for age and sex and were classified into risk groups for the development of malignant melanoma according to the Rigel classification.

RESULTS

MN on the buttocks were found in 23% of patients with AMS and 9% of control subjects (p < 0.003). In patients versus control subjects the mean number (1.3 vs 1.2, respectively) and mean diameter (5.7 vs 5.9 mm, respectively) of MN on the buttocks did not differ significantly. The MN in both patients and control subjects were not atypical clinically. The odds ratio for having AMS if MN were present on the buttocks was calculated to be 1.56 (95% confidence interval, 1.25 to 1.95).

CONCLUSION

Although the patients were 2.6 times more likely to have MN on their buttocks than the control subjects, clinically the MN did not differ significantly in number or appearance from those found on the buttocks of control subjects. It is hypothesized that the formation of some atypical MN requires direct solar radiation for their phenotypic expression.

Atypical mole syndrome: risk factor for cutaneous malignant melanoma and implications for management

The incidence of malignant melanoma is increasing faster than that of any other cancer. It is important to identify subsets of the population at high risk of its development so that they can be observed more closely to identify early melanomas when they are curable. It has been reported worldwide that persons with the atypical mole (dysplastic nevus) syndrome are such a subset at increased risk. A risk gradient for the development of melanoma exists and varies from persons with one or two atypical moles and no family history of melanoma at one end of the spectrum to persons with the familial atypical multiple-mole melanoma syndrome at the other. Guidelines for the management of atypical mole syndrome are presented.

Risk of developing cutaneous malignant melanoma in atypical-mole syndrome: New York University experience and literature review

The presence of atypical moles (AM) is considered to be a marker for an increased risk of developing cutaneous malignant melanoma (MM). The extent to which individuals with the atypical-mole syndrome (AMS) are at risk for developing MM is unknown. We present a review of the world literature and of our experience at New York University. We conclude that the presence of AMS in Caucasians significantly increases the risk of developing MM, regardless of geographic location. A further increase in MM risk is noted if there is a personal and/or family history of MM.

Dysplastic nevi can be diagnosed and graded reproducibly: a longitudinal study

BACKGROUND

Poor interobserver reproducibility in diagnosing and grading dysplastic melanocytic nevi is often cited as evidence against the ability of pathologists to recognize such an entity.

OBJECTIVE

We attempted to examine the diagnostic profiles of melanocytic lesions of two dermatopathologists in a stable population base.

METHODS

All 2600 melanocytic neoplasms were diagnosed at Stanford University Medical Center during the past 4 years by one dermatopathologist from 1987 to 1989 and a different dermatopathologist in 1990 and 1991. The two independently evaluated these lesions unaware of the other's criteria.

RESULTS

The diagnostic profile of the two pathologists shows a striking degree of similarity: 76.7% versus 75.3% of all nevi were diagnosed as acquired melanocytic nevi, 8.8% versus 12.0% were diagnosed as mildly dysplastic, 7.0% versus 6.8% as moderately dysplastic, and 2.7% versus 1.6% as severely dysplastic.

CONCLUSION

Our findings suggest that the two pathologists are using reproducible criteria for diagnosing and grading dysplastic nevi.

Histologic evaluation of pigmented lesions in Connecticut and its influence on the reporting of melanoma

BACKGROUND

Underreporting of melanoma to state tumor registries has been identified as a problem in gathering accurate statistics on melanoma incidence.

OBJECTIVE

Our purpose was to examine two factors that could influence the reporting of melanoma to the Connecticut Tumor Registry: histologic diagnosis of melanoma in the private offices of dermatologists and histologic diagnosis of melanoma in out-of-state laboratories.

METHODS

From December 1990 to April 1991, questionnaires were sent to all known practicing dermatologists in the state of Connecticut (N = 149). Of the 127 dermatologists who were eligible, 124 (97.6%) completed the survey.

RESULTS

The estimated number of melanomas diagnosed in private offices during 1990 was 9 to 18; this was based on the number of dermatologists who officially read their own slides (n = 19), the estimated number of melanomas diagnosed by these 19 dermatologists (n = 91), and the percentage of melanomas and uncertain pigmented lesion cases sent for consultation (80% to 90%). According to the estimates of Connecticut dermatologists, out-of-state laboratories diagnosed 84 of 523 melanomas (16%) in Connecticut residents.

CONCLUSION

The diagnosis of melanoma in private offices did not appear to be a significant factor in underreporting whereas the diagnosis of melanoma in out-of-state laboratories did appear to be more significant. However, the possibility exists that some of these latter melanomas would eventually be reported at the time of reexcision.

Prospective follow-up for malignant melanoma in patients with atypical-mole (dysplastic-nevus) syndrome

A total of 357 white patients who had melanocytic nevi that fulfilled the clinical criteria for the "classic" atypical-mole (dysplastic-nevus) syndrome (100 or more melanocytic nevi; one or more melanocytic nevi 8 mm or larger in diameter; and, one or more melanocytic nevi with atypical features) were followed for the development of cutaneous malignant melanomas. Seventeen patients (4.8%) developed malignant melanomas during an average follow-up period of 49 months. One patient developed two malignant melanomas. Eight of the malignant melanomas detected were in situ and ten were invasive melanomas (less than 0.86 mm in Breslow thickness), implying an excellent prognosis. The number of malignant melanomas detected in these patients exceeded significantly the number expected to occur in age- and sex-matched white controls. All groups were shown to have an increased risk for the development of malignant melanomas. Total-body photographs were helpful in detecting changes in size, shape, and color that led to the diagnosis of malignant melanoma. These data support the concept that patients with this readily regionalized clinical presentation of classic atypical-mole syndrome are at an increased risk for malignant melanomas and, therefore, should be examined regularly.