Prognostic modeling of cutaneous melanoma stage I patients using cancer registry data identifies subsets with very-low melanoma mortality.

BACKGROUND: Evidence exists that escalating melanoma incidence is due in part to overdiagnosis, the diagnosis of lesions that will not lead to symptoms or death. The authors aimed to characterize subsets of melanoma patients with very-low risk of death that may be contributing to overdiagnosis. METHODS: Melanoma patients diagnosed in 2010 and 2011 with stage I lesions ≤1.0 mm thick and negative clinical lymph nodes from the Surveillance, Epidemiology, and End Results database were selected. Classification and regression tree and logistic regression models were developed and validated to identify patients with very-low risk of death from melanoma within 7 years. Logistic models were also used to identify patients at higher risk of death among this group of stage I patients. RESULTS: Compared to an overall 7-year mortality from melanoma of 2.5% in these patients, a subset comprising 25% had a risk below 1%. Younger age at diagnosis and Clark level II were associated with low risk of death in all models. Breslow thickness below 0.4 mm, absence of mitogenicity, absence of ulceration, and female sex were also associated with lower mortality. A small subset of high-risk patients with >20% risk of death was also identified. CONCLUSION: Patients with very-low risk of dying from melanoma within 7 years of diagnosis were identified. Such cases warrant further study and consensus discussion to develop classification criteria, with the potential to be categorized using an alternative term such as "melanocytic neoplasms of low malignant potential." LAY SUMMARY: Although melanoma is the most serious skin cancer, most melanoma patients have high chances of survival. There is evidence that some lesions diagnosed as melanoma would never have caused symptoms or death, a phenomenon known as overdiagnosis. In this study, we used cancer registry data to identify a subset of early-stage melanoma patients with almost no melanoma deaths. Using two statistical approaches, we identified patients with <1% risk of dying from melanoma in 7 years. Such patients tended to be younger with minimal invasion into the skin. We also identified a very small patient subset with higher mortality risk.

Characterization of multiple diagnostic terms in melanocytic skin lesion pathology reports.

BACKGROUND: Histopathologically ambiguous melanocytic lesions lead some pathologists to list multiple diagnostic considerations in the pathology report. The frequency and circumstance of multiple diagnostic considerations remain poorly characterized. METHODS: Two hundred and forty skin biopsy samples were interpreted by 187 pathologists (8976 independent diagnoses) and classified according to a diagnostic/treatment stratification (MPATH-Dx). RESULTS: Multiple diagnoses in different MPATH-Dx classes were used in n = 1320 (14.7%) interpretations, with 97% of pathologists and 91% of cases having at least one such interpretation. Multiple diagnoses were more common for intermediate risk lesions and are associated with greater subjective difficulty and lower confidence. We estimate that 6% of pathology reports for melanocytic lesions in the United States contain two diagnoses of different MPATH-Dx prognostic classes, and 2% of cases are given two diagnoses with significant treatment implications. CONCLUSIONS: Difficult melanocytic diagnoses in skin may necessitate multiple diagnostic considerations; however, as patients increasingly access their health records and retrieve pathology reports (as mandated by US law), uncertainty should be expressed unambiguously.

Histopathological diagnosis of cutaneous melanocytic lesions: blinded and nonblinded second opinions offer similar improvement in diagnostic accuracy.

BACKGROUND: Previous studies of second opinions in the diagnosis of melanocytic skin lesions have examined blinded second opinions, which do not reflect usual clinical practice. The current study, conducted in the USA, investigated both blinded and nonblinded second opinions for their impact on diagnostic accuracy. METHODS: In total, 100 melanocytic skin biopsy cases, ranging from benign to invasive melanoma, were interpreted by 74 dermatopathologists. Subsequently, 151 dermatopathologists performed nonblinded second and third reviews. We compared the accuracy of single reviewers, second opinions obtained from independent, blinded reviewers and second opinions obtained from sequential, nonblinded reviewers. Accuracy was defined with respect to a consensus reference diagnosis. RESULTS: The mean case-level diagnostic accuracy of single reviewers was 65.3% (95% CI 63.4-67.2%). Second opinions arising from sequential, nonblinded reviewers significantly improved accuracy to 69.9% (95% CI 68.0-71.7%; P < 0.001). Similarly, second opinions arising from blinded reviewers improved upon the accuracy of single reviewers (69.2%; 95% CI 68.0-71.7%). Nonblinded reviewers were more likely than blinded reviewers to give diagnoses in the same diagnostic classes as the first diagnosis. Nonblinded reviewers tended to be more confident when they agreed with previous reviewers, even with inaccurate diagnoses. CONCLUSION: We found that both blinded and nonblinded second reviewers offered a similar modest improvement in diagnostic accuracy compared with single reviewers. Obtaining second opinions with knowledge of previous reviews tends to generate agreement among reviews, and may generate unwarranted confidence in an inaccurate diagnosis. Combining aspects of both blinded and nonblinded review in practice may leverage the advantages while mitigating the disadvantages of each approach. Specifically, a second pathologist could give an initial diagnosis blinded to the results of the first pathologist, with subsequent nonblinded discussion between the two pathologists if their diagnoses differ.

Histopathologic synoptic reporting of invasive melanoma: How reliable are the data?

BACKGROUND: Synoptic reporting is recommended by many guideline committees to encourage the thorough histologic documentation necessary for optimal management of patients with melanoma. METHODS: One hundred fifty-one pathologists from 40 US states interpreted 41 invasive melanoma cases. For each synoptic reporting factor, the authors identified cases with "complete agreement" (all participants recorded the same value) versus any disagreement. Pairwise agreement was calculated for each case as the proportion of pairs of responses that agreed, where paired responses were generated by the comparison of each reviewer's response with all others. RESULTS: There was complete agreement among all reviewers for 22 of the 41 cases (54%) on Breslow thickness dichotomized at 0.8 mm, with pairwise agreement ranging from 49% to 100% across the 41 cases. There was complete agreement for "no ulceration" in 24 of the 41 cases (59%), with pairwise agreement ranging from 42% to 100%. Tumor transected at base had complete agreement for 26 of the 41 cases (63%), with pairwise agreement ranging from 31% to 100%. Mitotic rate, categorized as 0/mm2 , 1/mm2 , or 2/mm2 , had complete agreement for 17 of the 41 cases (41%), with pairwise agreement ranging from 36% to 100%. Regression saw complete agreement for 14 of 41 cases (34%), with pairwise agreement ranging from 40% to 100%. Lymphovascular invasion, perineural invasion, and microscopic satellites were rarely reported as present. Respectively, these prognostic factors had complete agreement for 32 (78%), 37 (90%), and 18 (44%) of the 41 cases, and the ranges of pairwise agreement were 47% to 100%, 70% to 100%, and 53% to 100%, respectively. CONCLUSIONS: These findings alert pathologists and clinicians to the problem of interobserver variability in recording critical prognostic factors. LAY SUMMARY: This study addresses variability in the assessment and reporting of critical characteristics of invasive melanomas that are used by clinicians to guide patient care. The authors characterize the diagnostic variability among pathologists and their reporting methods in light of recently updated national guidelines. Results demonstrate considerable variability in the diagnostic reporting of melanoma with regard to the following: Breslow thickness, mitotic rate, ulceration, regression, and microscopic satellites. This work serves to alert pathologists and clinicians to the existence of variability in reporting these prognostic factors.

Terminology for melanocytic skin lesions and the MPATH-Dx classification schema: A survey of dermatopathologists.

BACKGROUND: Diagnostic terms used in histopathology reports of cutaneous melanocytic lesions are not standardized. We describe dermatopathologists' views regarding diverse diagnostic terminology and the utility of the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) for categorizing melanocytic lesions. METHODS: July 2018-2019 survey of board-certified and/or fellowship-trained dermatopathologists with experience interpreting melanocytic lesions. RESULTS: Among 160 participants, 99% reported witnessing different terminology being used for the same melanocytic lesion. Most viewed diverse terminology as confusing to primary care physicians (98%), frustrating to pathologists (83%), requiring more of their time as a consultant (64%), and providing necessary clinical information (52%). Most perceived that adoption of the MPATH-Dx would: improve communication with other pathologists and treating physicians (87%), generally be a change for the better (80%), improve patient care (79%), be acceptable to clinical colleagues (68%), save time in pathology report documentation (53%), and protect from malpractice (51%). CONCLUSIONS: Most dermatopathologists view diverse terminology as contributing to miscommunication with clinicians and patients, adversely impacting patient care. They view the MPATH-Dx as a promising tool to standardize terminology and improve communication. The MPATH-Dx may be a useful supplement to conventional pathology reports. Further revision and refinement are necessary for widespread clinical use.

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.

Factors associated with use of immunohistochemical markers in the histopathological diagnosis of cutaneous melanocytic lesions.

BACKGROUND: Melanocytic tumors are often challenging and constitute almost one in four skin biopsies. Immunohistochemical (IHC) studies may assist diagnosis; however, indications for their use are not standardized. METHODS: A test set of 240 skin biopsies of melanocytic tumors was examined by 187 pathologists from 10 US states, interpreting 48 cases in Phase I and either 36 or 48 cases in Phase II. Participant and diagnosis characteristics were compared between those who reported they would have ordered, or who would have not ordered IHC on individual cases. Intraobserver analysis examined consistency in the intent to order when pathologists interpreted the same cases on two occasions. RESULTS: Of 187 participants interpreting 48 cases each, 21 (11%) did not request IHC tests for any case, 85 (45%) requested testing for 1 to 6 cases, and 81 (43%) requested testing for ≥6 cases. Of 240 cases, 229 had at least one participant requesting testing. Only 2 out of 240 cases had more than 50% of participants requesting testing. Increased utilization of testing was associated with younger age of pathologist, board-certification in dermatopathology, low confidence in diagnosis, and lesions in intermediate MPATH-Dx classes 2 to 4. The median intraobserver concordance for requesting tests among 72 participants interpreting the same 48 cases in Phases I and II was 81% (IQR 73%-90%) and the median Kappa statistic was 0.20 (IQR 0.00, 0.39). CONCLUSION: Substantial variability exists among pathologists in utilizing IHC.

Pathologist characteristics associated with accuracy and reproducibility of melanocytic skin lesion interpretation.

BACKGROUND: Diagnostic interpretations of melanocytic skin lesions vary widely among pathologists, yet the underlying reasons remain unclear. OBJECTIVE: Identify pathologist characteristics associated with rates of accuracy and reproducibility. METHODS: Pathologists independently interpreted the same set of biopsy specimens from melanocytic lesions on 2 occasions. Diagnoses were categorized into 1 of 5 classes according to the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis system. Reproducibility was determined by pathologists' concordance of diagnoses across 2 occasions. Accuracy was defined by concordance with a consensus reference standard. Associations of pathologist characteristics with reproducibility and accuracy were assessed individually and in multivariable logistic regression models. RESULTS: Rates of diagnostic reproducibility and accuracy were highest among pathologists with board certification and/or fellowship training in dermatopathology and in those with 5 or more years of experience. In addition, accuracy was high among pathologists with a higher proportion of melanocytic lesions in their caseload composition and higher volume of melanocytic lesions. LIMITATIONS: Data gathered in a test set situation by using a classification tool not currently in clinical use. CONCLUSION: Diagnoses are more accurate among pathologists with specialty training and those with more experience interpreting melanocytic lesions. These findings support the practice of referring difficult cases to more experienced pathologists to improve diagnostic accuracy, although the impact of these referrals on patient outcomes requires additional research.

Complexities of perceived and actual performance in pathology interpretation: A comparison of cutaneous melanocytic skin and breast interpretations.

BACKGROUND: Little is known about how pathologists process differences between actual and perceived interpretations. OBJECTIVE: To compare perceived and actual diagnostic agreement before and after educational interventions. METHODS: Pathologists interpreted test sets of skin and/or breast specimens that included benign, atypical, in situ and invasive lesions. Interventions involved self-directed learning, one skin and one breast, that showed pathologists how their interpretations compared to a reference diagnoses. Prior to the educational intervention, participants estimated how their interpretations would compare to the reference diagnoses. After the intervention, participants estimated their overall agreement with the reference diagnoses. Perceived and actual agreements were compared. RESULTS: For pathologists interpreting skin, mean actual agreement was 52.4% and overall pre- and postinterventional mean perceived agreement was 72.9% vs 54.2%, an overestimated mean difference of 20.5% (95% confidence interval [CI] 17.2% to 24.0%) and 1.8% (95% CI -0.5% to 4.1%), respectively. For pathologists interpreting breast, mean actual agreement was 75.9% and overall pre- and postinterventional mean perceived agreement was 81.4% vs 76.9%, an overestimation of 5.5% (95% CI 3.0% to 8.0%) and 1.0% (95% CI 0.0% to 2.0%), respectively. CONCLUSIONS: Pathologists interpreting breast tissue had improved comprehension of their performance after the intervention compared to pathologists interpreting skin lesions.

Pathologists' Use of Second Opinions in Interpretation of Melanocytic Cutaneous Lesions: Policies, Practices, and Perceptions.

BACKGROUND: Research examining the role of second opinions in pathology for diagnosis of melanocytic lesions is limited. OBJECTIVE: To assess current laboratory policies, clinical use of second opinions, and pathologists' perceptions of second opinions for melanocytic lesions. MATERIALS AND METHODS: Cross-sectional data collected from 207 pathologists in 10 US states who diagnose melanocytic lesions. The web-based survey ascertained pathologists' professional information, laboratory second opinion policy, use of second opinions, and perceptions of second opinion value for melanocytic lesions. RESULTS: Laboratory policies required second opinions for 31% of pathologists and most commonly required for melanoma in situ (26%) and invasive melanoma (30%). In practice, most pathologists reported requesting second opinions for melanocytic tumors of uncertain malignant potential (85%) and atypical Spitzoid lesions (88%). Most pathologists perceived that second opinions increased interpretive accuracy (78%) and protected them from malpractice lawsuits (62%). CONCLUSION: Use of second opinions in clinical practice is greater than that required by laboratory policies, especially for melanocytic tumors of uncertain malignant potential and atypical Spitzoid lesions. Quality of care in surgical interventions for atypical melanocytic proliferations critically depends on the accuracy of diagnosis in pathology reporting. Future research should examine the extent to which second opinions improve accuracy of melanocytic lesion diagnosis.

Characteristics and diagnostic performance of pathologists who enjoy interpreting melanocytic lesions.

Diagnostic discrepancy among pathologists interpreting melanocytic skin lesions (MSL) is an ongoing concern for patient care. Given that job satisfaction could impact patient care, this study aimed to characterize which pathologists enjoy interpreting MSL and estimate the association between enjoyment and diagnostic accuracy. Pathologists' demographics, training, and experience were obtained by a cross-sectional survey. Associations between these characteristics and self-reported enjoyment when interpreting MSL were estimated by Pearson's Chi-square tests. Diagnostic accuracy was determined by comparing pathologists' MSL interpretations with reference standard diagnoses. Associations between enjoyment and diagnostic accuracy were evaluated by generalized estimating equations (GEE) models. One hundred and eighty-seven (90%) pathologists completed the study. Seventy percent agreed that interpreting MSL is enjoyable. Pathologists who enjoyed interpreting MSL were more likely to be board certified and/or fellowship trained in dermatopathology (P=0.008), have ?10 years of experience (P=0.010) and have an MSL caseload of ?60 per month (P=<0.001). After adjustment, there was no association between enjoyment and diagnostic accuracy. Our data suggest that job dissatisfaction does not adversely affect diagnostic accuracy in the interpretation of melanocytic lesions, which is of importance given the progressive increase in annual biopsy rates and the attendant work demands imposed on pathologists.

The influence of tumor regression, solar elastosis, and patient age on pathologists' interpretation of melanocytic skin lesions.

It is not known whether patient age or tumor characteristics such as tumor regression or solar elastosis influence pathologists' interpretation of melanocytic skin lesions (MSLs). We undertook a study to determine the influence of these factors, and to explore pathologist's characteristics associated with the direction of diagnosis. To meet our objective, we designed a cross-sectional survey study of pathologists' clinical practices and perceptions. Pathologists were recruited from diverse practices in 10 states in the United States. We enrolled 207 pathologist participants whose practice included the interpretation of MSLs. Our findings indicated that the majority of pathologists (54.6%) were influenced toward a less severe diagnosis when patients were <30 years of age. Most pathologists were influenced toward a more severe diagnosis when patients were >70 years of age, or by the presence of tumor regression or solar elastosis (58.5%, 71.0%, and 57.0%, respectively). Generally, pathologists with dermatopathology board certification and/or a high caseload of MSLs were more likely to be influenced, whereas those with more years' experience interpreting MSL were less likely to be influenced. Our findings indicate that the interpretation of MSLs is influenced by patient age, tumor regression, and solar elastosis; such influence is associated with dermatopathology training and higher caseload, consistent with expertise and an appreciation of lesion complexity.

Variation among pathologists' treatment suggestions for melanocytic lesions: A survey of pathologists.

BACKGROUND: The extent of variability in treatment suggestions for melanocytic lesions made by pathologists is unknown. OBJECTIVE: We investigated how often pathologists rendered suggestions, reasons for providing suggestions, and concordance with national guidelines. METHODS: We conducted a cross-sectional survey of pathologists. Data included physician characteristics, experience, and treatment recommendation practices. RESULTS: Of 301 pathologists, 207 (69%) from 10 states (California, Connecticut, Hawaii, Iowa, Kentucky, Louisiana, New Jersey, New Mexico, Utah, and Washington) enrolled. In all, 15% and 7% reported never and always including suggestions, respectively. Reasons for offering suggestions included improved care (79%), clarification (68%), and legal liability (39%). Reasons for not offering suggestions included referring physician preference (48%), lack of clinical information (44%), and expertise (29%). Training and caseload were associated with offering suggestions (P < .05). Physician suggestions were most consistent for mild/moderate dysplastic nevi and melanoma. For melanoma in situ, 18 (9%) and 32 (15%) pathologists made suggestions that undertreated or overtreated lesions based on National Comprehensive Cancer Network (NCCN) guidelines, respectively. For invasive melanoma, 14 (7%) pathologists made treatment suggestions that undertreated lesions based on NCCN guidelines. LIMITATIONS: Treatment suggestions were self-reported. CONCLUSIONS: Pathologists made recommendations ranging in consistency. These findings may inform efforts to reduce treatment variability and optimize patterns of care delivery for patients.

The utilization of spitz-related nomenclature in the histological interpretation of cutaneous melanocytic lesions by practicing pathologists: results from the M-Path study.

BACKGROUND: Spitz nevi, atypical Spitz tumors and spitzoid melanomas ('spitzoid lesions') represent controversial and poorly understood cutaneous melanocytic lesions that are difficult to diagnose histologically. It is unknown how these terms are used by pathologists. METHODS: We describe use of Spitz-related terminology using data from the Melanoma Pathology (M-Path) study database comprising pathologists' interpretations of biopsy slides, a nation-wide study evaluating practicing US pathologists' (N = 187) diagnoses of melanocytic lesions (8976 independent diagnostic assessments on 240 total test cases, with 1 slide per case). RESULTS: Most pathologists (90%) used the Spitz-related terminology. However, significant variation exists in which specific lesions were diagnosed as spitzoid and in the corresponding treatment recommendations. Recommendations ranged from 'no further treatment' to 'wide excision of 10 mm or greater' with no category capturing more than 50% of responses. For spitzoid melanoma diagnoses, 90% of pathologists recommended excision with ≥10 mm margin. Pathologists report less confidence in diagnosing these lesions compared with other melanocytic proliferations and are more likely to request second opinions and additional clinical information (all p < 0.05). CONCLUSIONS: Spitzoid lesions are often not classified in any standardized way, evoke uncertainty in diagnosis by pathologists, and elicit variability in treatment recommendations.

How concerns and experiences with medical malpractice affect dermatopathologists' perceptions of their diagnostic practices when interpreting cutaneous melanocytic lesions.

OBJECTIVE: We sought to identify characteristics associated with past malpractice lawsuits and how malpractice concerns may affect interpretive practices. METHODS: We surveyed 207 of 301 (68.8%) eligible dermatopathologists who interpret melanocytic skin lesions in 10 states. The survey assessed dermatopathologists' demographic and clinical practice characteristics, perceptions of how medical malpractice concerns could influence their interpretive practices, and past malpractice lawsuits. RESULTS: Of dermatopathologists, 33% reported past malpractice experiences. Factors associated with being sued included older age (57 vs 48 years, P < .001), lack of board certification or fellowship training in dermatopathology (76.5% vs 53.2%, P = .001), and greater number of years interpreting melanocytic lesions (>20 years: 52.9% vs 20.1%, P < .001). Of participants, 64% reported being moderately or extremely confident in their melanocytic interpretations. Although most dermatopathologists believed that malpractice concerns increased their likelihood of ordering specialized pathology tests, obtaining recuts, and seeking a second opinion, none of these practices were associated with past malpractice. Most dermatopathologists reported concerns about potential harms to patients that may result from their assessments of melanocytic lesions. LIMITATIONS: Limitations of this study include lack of validation of and details about the malpractice suits experienced by participating dermatopathologists. In addition, the study assessed perceptions of practice rather than actual practices that might be associated with malpractice incidents. CONCLUSIONS: Most dermatopathologists reported apprehension about how malpractice affects their clinical practice and are concerned about patient safety irrespective of whether they had actually experienced a medical malpractice suit.

Evaluation of the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) classification scheme for diagnosis of cutaneous melanocytic neoplasms: Results from the International Melanoma Pathology Study Group.

BACKGROUND: Pathologists use diverse terminology when interpreting melanocytic neoplasms, potentially compromising quality of care. OBJECTIVE: We sought to evaluate the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) scheme, a 5-category classification system for melanocytic lesions. METHODS: Participants (n = 16) of the 2013 International Melanoma Pathology Study Group Workshop provided independent case-level diagnoses and treatment suggestions for 48 melanocytic lesions. Individual diagnoses (including, when necessary, least and most severe diagnoses) were mapped to corresponding MPATH-Dx classes. Interrater agreement and correlation between MPATH-Dx categorization and treatment suggestions were evaluated. RESULTS: Most participants were board-certified dermatopathologists (n = 15), age 50 years or older (n = 12), male (n = 9), based in the United States (n = 11), and primary academic faculty (n = 14). Overall, participants generated 634 case-level diagnoses with treatment suggestions. Mean weighted kappa coefficients for diagnostic agreement after MPATH-Dx mapping (assuming least and most severe diagnoses, when necessary) were 0.70 (95% confidence interval 0.68-0.71) and 0.72 (95% confidence interval 0.71-0.73), respectively, whereas correlation between MPATH-Dx categorization and treatment suggestions was 0.91. LIMITATIONS: This was a small sample size of experienced pathologists in a testing situation. CONCLUSION: Varying diagnostic nomenclature can be classified into a concise hierarchy using the MPATH-Dx scheme. Further research is needed to determine whether this classification system can facilitate diagnostic concordance in general pathology practice and improve patient care.

The self-reported use of immunostains and cytogenetic testing in the diagnosis of melanoma by practicing U.S. pathologists of 10 selected states.

BACKGROUNDS: The diagnosis of melanoma can be challenging, especially in lesions for which the histopathologic criteria bridge two or more taxonomic categories. Newer genomic analytical methods of fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) have been introduced as ancillary techniques to differentiate benign and malignant melanocytic proliferations. METHODS: We evaluated how pathologists perceive and are incorporating these new cytogenetic testing technologies into their practices. We conducted a study of 207 U.S. pathologists who interpret melanocytic lesions in clinical practice in 10 SEER states. Pathologists were surveyed regarding perceptions and utilization of FISH and/or CGH in their clinical practices. RESULTS: Results showed that 38% of pathologists use FISH and/or CGH in interpreting melanocytic lesions. Pathologists reporting FISH and/or CGH use were significantly younger (p < 0.05), were fellowship trained or board certified in dermatopathology (p < 0.001) and were affiliated with an academic institute (p < 0.001). Pathologists reporting that their colleagues consider them an expert in the assessment of melanocytic lesions were more likely to employ FISH and/or CGH in their practices than non-experts. CONCLUSIONS: Early users of cytogenetic testing technologies in cutaneous pathology are more likely to be younger, affiliated with an academic institution and fellowship trained or board certified in dermatopathology.

Achieving consensus for the histopathologic diagnosis of melanocytic lesions: use of the modified Delphi method.

OBJECTIVE: To understand the sophisticated nature of coming to consensus when diagnosing complex melanocytic lesions among a panel of experienced dermatopathologists. METHODS: A total of 240 melanocytic lesions were assessed independently by three experienced dermatopathologists with their diagnoses mapped into one of five Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-DX) categories: (I) nevus/mild atypia, (II) moderate atypia, (III) severe atypia/melanoma in situ, (IV) T1a invasive melanoma and (V) ≥ T1b invasive melanoma. The dermatopathologists then discussed the cases, using a modified Delphi method to facilitated consensus building for cases with discordant diagnoses. RESULTS: For most cases, a majority of interpretations (two or three of three) agreed with the consensus diagnosis in 95% of Category I, 64% of Category II, 84% of Category III, 88% for Category IV and 100% of Category V cases. Disagreements were typically due to diagnostic threshold differences (64.5%), differing contents on slides even though the slides were sequential cuts (18.5%), and missed findings (15.3%). Disagreements were resolved via discussion of histopathologic features and their significance while reviewing the slides using a multi-headed microscope, considering treatment recommendations, citing existing literature, reviewing additional slides for a case, and choosing a provisional/borderline diagnosis to capture diverse opinions. All experienced pathologists participating in this study reported that the process of coming to consensus was challenging for borderline cases and may have represented compromise rather than consensus. They also reported the process changed their approaches to diagnosing complex melanocytic lesions. CONCLUSIONS: The most frequent reason for disagreement of experienced dermatopathologists was differences in diagnostic thresholds related to observer viewpoints. A range of approaches was needed to come to consensus, and this may guide pathology groups who do not currently hold consensus conferences.

Cellular Blue Nevomelanocytic Lesions: Analysis of Clinical, Histological, and Outcome Data in 37 Cases.

Cellular blue nevomelanocytic lesions (CBNLs) frequently pose diagnostic problems to pathologists, and their biological potential may be difficult to establish. In this study, the authors have analyzed the clinical, histological, and outcome data of 37 cellular blue nevomelanocytic lesions and the molecular characteristics of 4 lesions. The cohort of cases comprised 8 cellular blue nevi (CBNs), 17 atypical cellular blue nevi (ACBNs), and 12 blue-nevus-like melanomas (BNLMs) with a mean follow-up of 5 years. The average age at diagnosis was 25.9 years for patients with ACBN, versus 30.4 years for CBN, and 44.6 years for BNLM. Both CBN and ACBN occurred most frequently on the trunk or extremities, whereas BNLM primarily involved the scalp. Histologically, CBN and ACBN were characterized by a mean diameter of <1 cm, absence of necrosis, low mitotic rate (mean: 1-2 mitotic figures/mm), little or no infiltrative properties, and usually low-grade cytologic atypia. In contrast, BNLM had a mean diameter of 1.6 cm, necrosis, tissue infiltration, greater mitotic activity (mean: 6 mitotic figures/mm), and high-grade cytologic atypia. ACBNs often were larger, more densely cellular, exhibited higher mitotic counts, and were cytologically more atypical than CBN. Seven CBN cases with follow-up had a benign clinical course (average follow-up of 4.7 years). Among 6 patients with ACBN who underwent sentinel lymph node (SLN) biopsy, 3 were positive, and a single additional case had 1 positive non-SLN (this patient did not have a SLN biopsy performed). All 14 cases of ACBN with follow-up were alive and without recurrence with mean follow-up of 5 years. Of the 9 melanoma cases with follow-up, 3 patients with SLN and non-SLN involvement died from their disease (average follow-up of 4.8 years). Array comparative genomic hybridization was performed on 2 ACBNs and 1 BNLM: One of the 2 ACBNs showed chromosomal aberrations and 1 BNLM showed multiple chromosomal gains and losses. Multiplex polymerase chain reaction was performed on 1 ACBN, and no mutations were found. From these results, the authors conclude that ACBN occupy an intermediate position within the spectrum of CBN and BNLM, yet many lesions cannot be reliably distinguished from either CBN or BNLM because of overlapping histologic features. However, in general, ACBNs seem to aggregate more closely with CBN in terms of clinical, histological, molecular profile (limited data), and biological behavior.

Use of Digital Whole Slide Imaging in Dermatopathology.

Digital whole slide imaging (WSI) is an emerging technology for pathology interpretation, with specific challenges for dermatopathology, yet little is known about pathologists' practice patterns or perceptions regarding WSI for interpretation of melanocytic lesions. A national sample of pathologists (N = 207) was recruited from 864 invited pathologists from ten US states (CA, CT, HI, IA, KY, LA, NJ, NM, UT, and WA). Pathologists who had interpreted melanocytic lesions in the past year were surveyed in this cross-sectional study. The survey included questions on pathologists' experience, WSI practice patterns and perceptions using a 6-point Likert scale. Agreement was summarized with descriptive statistics to characterize pathologists' use and perceptions of WSI. The majority of participating pathologists were between 40 and 59 years of age (62%) and not affiliated with an academic medical center (71%). Use of WSI was seen more often among dermatopathologists and participants affiliated with an academic medical center. Experience with WSI was reported by 41%, with the most common type of use being for education and testing (CME, board exams, and teaching in general, 71%), and clinical use at tumor boards and conferences (44%). Most respondents (77%) agreed that accurate diagnoses can be made with this technology, and 59% agreed that benefits of WSI outweigh concerns. However, 78% of pathologists reported that digital slides are too slow for routine clinical interpretation. The respondents were equally split as to whether they would like to adopt WSI (49%) or not (51%). The majority of pathologists who interpret melanocytic lesions do not use WSI, but among pathologists who do, use is largely for CME, licensure/board exams, and teaching. Positive perceptions regarding WSI slightly outweigh negative perceptions. Understanding practice patterns with WSI as dissemination advances may facilitate concordance of perceptions with adoption of the technology.