Immunohistochemistry for Diagnosing Melanoma in Older Adults.

Importance: Pathologic assessment to diagnose skin biopsies, especially for cutaneous melanoma, can be challenging, and immunohistochemistry (IHC) staining has the potential to aid decision-making. Currently, the temporal trends regarding the use of IHC for the examination of skin biopsies on a national level have not been described. Objective: To illustrate trends in the use of IHC for the examination of skin biopsies in melanoma diagnoses. Design, Setting, and Participants: A retrospective cross-sectional study was conducted to examine incident cases of melanoma diagnosed between January 2000 and December 2017. The analysis used the SEER-Medicare linked database, incorporating data from 17 population-based registries. The study focused on incident cases of in situ or malignant melanoma of the skin diagnosed in patients 65 years or older. Data were analyzed between August 2022 and November 2023. Main Outcomes and Measures: The main outcomes encompassed the identification of claims for IHC within the month of melanoma diagnoses and extending up to 14 days into the month following diagnosis. The SEER data on patients with melanoma comprised demographic, tumor, and area-level characteristics. Results: The final sample comprised 132 547 melanoma tumors in 116 117 distinct patients. Of the 132 547 melanoma diagnoses meeting inclusion criteria from 2000 to 2017, 43 396 cases had accompanying IHC claims (33%). Among these cases, 28 298 (65%) were diagnosed in male patients, 19 019 (44%) were diagnosed in patients aged 65 years to 74 years, 16 444 (38%) in patients aged 75 years to 84 years, and 7933 (18%) in patients aged 85 years and older. In 2000, 11% of melanoma cases had claims for IHC at or near the time of diagnosis. This proportion increased yearly, with 51% of melanoma cases having associated IHC claims in 2017. Increasing IHC use is observed for all stages of melanoma, including in situ melanoma. Claims for IHC in melanomas increased in all 17 SEER registries but at different rates. In 2017, the use of IHC for melanoma diagnosis ranged from 39% to 68% across registries. Conclusions and Relevance: Considering the dramatically rising and variable use of IHC in diagnosing melanoma by pathologists demonstrated in this retrospective cross-sectional study, further investigation is warranted to understand the clinical utility and discern when IHC most improves diagnostic accuracy or helps patients.

Pathologist Characteristics Associated With Rendering Higher-Grade Diagnoses for Melanocytic Lesions.

Importance: The incidence of melanoma diagnoses has been increasing in recent decades, and controlled studies have indicated high histopathologic discordance across the intermediate range of melanocytic lesions. The respective causes for these phenomena remain incompletely understood. Objective: To identify pathologist characteristics associated with tendencies to diagnose melanocytic lesions as higher grade vs lower grade or to diagnose invasive melanoma vs any less severe diagnosis. Design, Setting, and Participants: This exploratory study used data from 2 nationwide studies (the Melanoma Pathology [M-Path] study, conducted from July 2013 to May 2016, and the Reducing Errors in Melanocytic Interpretations [REMI] study, conducted from August 2018 to March 2021) in which participating pathologists who interpreted melanocytic lesions in their clinical practices interpreted study cases in glass slide format. Each pathologist was randomly assigned to interpret a set of study cases from a repository of skin biopsy samples of melanocytic lesions; each case was independently interpreted by multiple pathologists. Data were analyzed from July 2022 to February 2023. Main Outcomes and Measures: The association of pathologist characteristics with diagnosis of a study case as higher grade (including severely dysplastic and melanoma in situ) vs lower grade (including mild to moderately dysplastic nevi) and diagnosis of invasive melanoma vs any less severe diagnosis was assessed using logistic regression. Characteristics included demographics (age, gender, and geographic region), years of experience, academic affiliation, caseload of melanocytic lesions in their practice, specialty training, and history of malpractice suits. Results: A total of 338 pathologists were included: 113 general pathologists and 74 dermatopathologists from M-Path and 151 dermatopathologists from REMI. The predominant factor associated with rendering more severe diagnoses was specialist training in dermatopathology (board certification and/or fellowship training). Pathologists with this training were more likely to render higher-grade diagnoses (odds ratio [OR], 2.63; 95% CI, 2.10-3.30; P < .001) and to diagnose invasive melanoma (OR, 1.95; 95% CI, 1.53-2.49; P < .001) than pathologists without this training interpreting the same case. Nonmitogenic pT1a diagnoses (stage pT1a melanomas with no mitotic activity) accounted for the observed difference in diagnosis of invasive melanoma; when these lesions, which carry a low risk of metastasis, were grouped with the less severe diagnoses, there was no observed association (OR, 0.95; 95% CI, 0.74-1.23; P = .71). Among dermatopathologists, those with a higher caseload of melanocytic lesions in their practice were more likely to assign higher-grade diagnoses (OR for trend, 1.27; 95% CI, 1.04-1.56; P = .02). Conclusions and Relevance: The findings suggest that specialty training in dermatopathology is associated with a greater tendency to diagnose atypical melanocytic proliferations as pT1a melanomas. These low-risk melanomas constitute a growing proportion of melanomas diagnosed in the US.

Implementing the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis: Long-term effect of a simple educational intervention.

Background: A standardized pathology management tool for melanocytic skin lesions may improve patient care by simplifying interpretation and categorization of the diverse terminology currently extant. Objective: To assess an online educational intervention that teaches dermatopathologists to use the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx), a schema collapsing multiple diagnostic terms into 5 classes ranging from benign to invasive melanoma. Methods: Practicing dermatopathologists (N = 149) from 40 US states participated in a 2-year educational intervention study (71% response rate). The intervention involved a brief tutorial followed by practice on 28 melanocytic lesions, with the goal of teaching pathologists how to correctly use the MPATH-Dx schema; competence using the MPATH-Dx tool 12-24 months postintervention was assessed. Participants' self-reported confidence using the MPATH-Dx tool was assessed preintervention and postintervention. Results: At preintervention, confidence using the MPATH-Dx tool was already high, despite 68% lacking prior familiarity with it, and confidence increased postintervention (P = .0003). During the intervention, participants used the MPATH-Dx tool correctly for 90% of their interpretations; postintervention, participants used the MPATH-Dx tool correctly for 88% of their interpretations. Limitations: Future research should examine implementing a standardized pathology assessment schema in actual clinical practice. Conclusion: Dermatopathologists can be taught to confidently and competently use the MPATH-Dx schema with a simple educational tutorial followed by practice.

Diagnostic error, uncertainty, and overdiagnosis in melanoma.

Diagnostic error can be defined as deviation from a gold standard diagnosis, typically defined in terms of expert opinion, although sometimes in terms of unexpected events that might occur in follow-up (such as progression and death from disease). Although diagnostic error does exist for melanoma, deviations from gold standard diagnosis, certainly among appropriately trained and experienced practitioners, are likely to be the result of uncertainty and lack of specific criteria, and differences of opinion, rather than lack of diagnostic skills. In this review, the concept of diagnostic error will be considered in relation to diagnostic uncertainty, and the concept of overdiagnosis in melanoma will be presented and discussed.

Revision of the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis Classification Schema for Melanocytic Lesions: A Consensus Statement.

Importance: A standardized pathology classification system for melanocytic lesions is needed to aid both pathologists and clinicians in cataloging currently existing diverse terminologies and in the diagnosis and treatment of patients. The Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis (MPATH-Dx) has been developed for this purpose. Objective: To revise the MPATH-Dx version 1.0 classification tool, using feedback from dermatopathologists participating in the National Institutes of Health-funded Reducing Errors in Melanocytic Interpretations (REMI) Study and from members of the International Melanoma Pathology Study Group (IMPSG). Evidence Review: Practicing dermatopathologists recruited from 40 US states participated in the 2-year REMI study and provided feedback on the MPATH-Dx version 1.0 tool. Independently, member dermatopathologists participating in an IMPSG workshop dedicated to the MPATH-Dx schema provided additional input for refining the MPATH-Dx tool. A reference panel of 3 dermatopathologists, the original authors of the MPATH-Dx version 1.0 tool, integrated all feedback into an updated and refined MPATH-Dx version 2.0. Findings: The new MPATH-Dx version 2.0 schema simplifies the original 5-class hierarchy into 4 classes to improve diagnostic concordance and to provide more explicit guidance in the treatment of patients. This new version also has clearly defined histopathological criteria for classification of classes I and II lesions; has specific provisions for the most frequently encountered low-cumulative sun damage pathway of melanoma progression, as well as other, less common World Health Organization pathways to melanoma; provides guidance for classifying intermediate class II tumors vs melanoma; and recognizes a subset of pT1a melanomas with very low risk and possible eventual reclassification as neoplasms lacking criteria for melanoma. Conclusions and Relevance: The implementation of the newly revised MPATH-Dx version 2.0 schema into clinical practice is anticipated to provide a robust tool and adjunct for standardized diagnostic reporting of melanocytic lesions and management of patients to the benefit of both health care practitioners and patients.

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.

Effect of Prior Diagnoses on Dermatopathologists' Interpretations of Melanocytic Lesions: A Randomized Controlled Trial.

Importance: Medical second opinions are common, although little is known about the best processes for obtaining them. This study assesses whether knowledge of a prior physician's diagnosis influences consulting physicians' diagnoses. Objective: To measure the extent to which dermatopathologists' diagnoses are influenced by prior diagnostic information from another dermatopathologist. Design, Setting, and Participants: Dermatopathologists were randomly assigned to interpret 1 slide set of 18 melanocytic skin biopsy specimens in 2 phases (5 slide sets totaling 90 cases). Phase 1 interpretations were conducted without prior diagnostic information. After a washout period of 12 or more months, dermatopathologists' phase 2 interpretations were conducted with their identical slide set; for a random subset of cases in phase 2, participants were shown prior diagnoses by other dermatopathologists that were either more or less severe than their own phase 1 diagnosis of the case. Using the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis tool, cases ranged from class I (benign) to class V (≥pT1b invasive melanoma). Data collection took place from August 2018 to March 2021, and data analysis was performed from March to December 2021. Intervention: Prior diagnoses were actual diagnoses from board-certified and/or fellowship-trained dermatopathologists. A prior diagnosis was always in a more severe or less severe diagnostic class than the participant's phase 1 interpretation; more or less severe was determined by the randomization scheme. In the control condition of no prior diagnostic information, the participants were told that a prior diagnosis was not available. Main Outcomes and Measures: When exposure was to a prior diagnosis in a higher diagnostic class, the primary study outcome was whether a participant's diagnosis in phase 2 was in a higher diagnostic class than the participant's diagnosis in phase 1. When exposure was to a prior diagnosis in a lower diagnostic class, the primary study outcome was whether a participant's diagnosis in phase 2 was in a lower diagnostic class than the participant's diagnosis in phase 1. The effect of prior diagnostic information was measured using the relative risk (RR) of each outcome relative to the control condition of no prior diagnostic information, adjusted for the diagnostic class of the phase 1 diagnosis. Prior to data collection, it was hypothesized that participants would be swayed in the direction of prior diagnostic information. Results: A total of 149 dermatopathologists (median [range] age, 47 years [34-76] years; 101 [68%] were male) provided 5322 interpretations of study cases. Participants were more likely to increase the severity of their diagnosis when the prior diagnosis was of greater severity compared with when no prior diagnosis was provided (RR, 1.52; 95% CI, 1.34-1.73); likewise, participants gave less severe diagnoses when prior diagnoses were of lesser severity (RR, 1.38; 95% CI, 1.19-1.59). Trends were similar among dermatopathologists who had previously stated they were "not at all influenced" by prior diagnoses. Prior diagnoses also swayed dermatopathologists away from correct diagnoses. Conclusions and Relevance: In this randomized controlled trial, despite the preference of most dermatopathologists to receive prior diagnoses when providing second opinions, this information swayed them away from a correct diagnosis to an incorrect diagnosis.

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.

Dermatopathologist Perceptions of Overdiagnosis of Melanocytic Skin Lesions and Association With Diagnostic Behaviors.

Importance: Despite evidence of overdiagnosis of in situ and invasive melanoma, neither the perceptions of practicing dermatopathologists about overdiagnosis nor possible associations between perceptions of overdiagnosis and diagnostic practices have been studied. Objective: To examine practicing US dermatopathologists' perceptions of melanoma overdiagnosis as a public health issue, and to associate diagnostic behaviors of dermatopathologists with perceptions of melanoma overdiagnosis. Design, Setting, and Participants: This survey study included 115 board-certified and/or fellowship-trained dermatopathologists and their diagnostic interpretations on a set of 18 skin biopsy cases (5 slide sets comprising 90 melanocytic skin lesions). Participants interpreted cases remotely using their own microscopes. Survey invitations occurred during 2018 to 2019, with data collection completed 2021. Data analysis was performed from June to September 2021. Main Outcomes and Measures: Agreement vs disagreement that overdiagnosis is a public health issue for atypical nevi, melanoma in situ, and invasive melanoma. Associations between perceptions regarding overdiagnosis and interpretive behavior on study cases. Results: Of 115 dermatopathologists, 68% (95% CI, 59%-76%) agreed that overdiagnosis is a public health issue for atypical nevi; 47% (95% CI, 38%-56%) for melanoma in situ; and 35% (95% CI, 26%-43%) for invasive melanoma. Dermatopathologists with more years in practice were significantly less likely to perceive that atypical nevi are overdiagnosed, eg, 46% of dermatopathologists with 20 or more years of experience agreed that atypical nevi are overdiagnosed compared with 93% of dermatopathologists with 1 to 4 years of experience. Compared with other dermatopathologists, those who agreed that all 3 conditions are overdiagnosed were slightly more likely to diagnose study cases as mild to moderately dysplastic nevi (odds ratio, 1.26; 95% CI, 0.97-1.64; P = .08), but the difference was not statistically significant. Dermatopathologists who agreed that invasive melanoma is overdiagnosed did not significantly differ in diagnosing invasive melanoma for study cases compared with those who disagreed (odds ratio, 1.10; 95% CI, 0.86-1.41; P = .44). Conclusions and Relevance: In this survey study, about two-thirds of dermatopathologists thought that atypical nevi are overdiagnosed, half thought that melanoma in situ is overdiagnosed, and one-third thought that invasive melanoma is overdiagnosed. No statistically significant associations were found between perceptions about overdiagnosis and interpretive behavior when diagnosing skin biopsy cases.

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.

Impact of Next-generation Sequencing on Interobserver Agreement and Diagnosis of Spitzoid Neoplasms.

Atypical Spitzoid melanocytic tumors are diagnostically challenging. Many studies have suggested various genomic markers to improve classification and prognostication. We aimed to assess whether next-generation sequencing studies using the Tempus xO assay assessing mutations in 1711 cancer-related genes and performing whole transcriptome mRNA sequencing for structural alterations could improve diagnostic agreement and accuracy in assessing neoplasms with Spitzoid histologic features. Twenty expert pathologists were asked to review 70 consultation level cases with Spitzoid features, once with limited clinical information and again with additional genomic information. There was an improvement in overall agreement with additional genomic information. Most significantly, there was increase in agreement of the diagnosis of conventional melanoma from moderate (κ=0.470, SE=0.0105) to substantial (κ=0.645, SE=0.0143) as measured by an average Cohen κ. Clinical follow-up was available in all 70 cases which substantiated that the improved agreement was clinically significant. Among 3 patients with distant metastatic disease, there was a highly significant increase in diagnostic recognition of the cases as conventional melanoma with genomics (P<0.005). In one case, none of 20 pathologists recognized a tumor with BRAF and TERT promoter mutations associated with fatal outcome as a conventional melanoma when only limited clinical information was provided, whereas 60% of pathologists correctly diagnosed this case when genomic information was also available. There was also a significant improvement in agreement of which lesions should be classified in the Spitz category/WHO Pathway from an average Cohen κ of 0.360 (SE=0.00921) to 0.607 (SE=0.0232) with genomics.

Association of Second-Opinion Strategies in the Histopathologic Diagnosis of Cutaneous Melanocytic Lesions With Diagnostic Accuracy and Population-Level Costs.

IMPORTANCE: Diagnostic variation among pathologists interpreting cutaneous melanocytic lesions could lead to suboptimal care. OBJECTIVE: To estimate the potential association of second-opinion strategies in the histopathologic diagnosis of cutaneous melanocytic lesions with diagnostic accuracy and 1-year population-level costs in the US. DESIGN, SETTING, AND PARTICIPANTS: Decision analysis with 1-year time horizon including melanocytic lesion diagnoses available from US pathologists participating in the Melanoma Pathology Study (M-Path) and from the study panel of reference pathologists who classified cases using the MPATH-Dx classification tool. M-Path data collection occurred from July 2013 through March 2015; analyses for the present study were performed between April 2015 and January 2021. EXPOSURES: Various second-opinion strategies for interpretation of melanocytic cutaneous lesions. MAIN OUTCOMES AND MEASURES: Estimated accuracy of pathologists' diagnoses, defined as concordance with the reference panel diagnoses, and 1-year postbiopsy medical costs under various second-opinion strategies. Expected percentage of concordant diagnoses, including percentages of overinterpretation and underinterpretation, and 1-year costs of medical care per 100 000 in the US population. RESULTS: Decision-analytic model parameters were based on diagnostic interpretations for 240 cases by 187 pathologists compared with reference panel diagnoses. Without second opinions, 83.2% of diagnoses in the US were estimated to be accurate-ie, concordant with the reference diagnosis; with overinterpretation (8.0%) or underinterpretation (8.8%), and 16 850 misclassified diagnoses per 100 000 biopsies. Accuracy increased under all second-opinion strategies. Accuracy (87.4% concordance with 3.6% overinterpretation and 9.1% underinterpretation) and cost (an increase of more than $10 million per 100 000 biopsies per year) were highest when second opinions were universal (eg, performed on all biopsies), relative to no second opinions. A selective second-opinion strategy based on pathologists' desire or institutional requirements for a second opinion was most accurate (86.5% concordance; 4.4% overinterpretation; 9.1% underinterpretation) and would reduce costs by more than $1.9 million per 100 000 skin biopsies relative to no second opinions. Improvements in diagnostic accuracy with all second-opinion strategies were associated with reductions in overinterpretation but not underinterpretation. CONCLUSIONS AND RELEVANCE: In this decision-analytic model, selective second-opinion strategies for interpretation of melanocytic skin lesions showed the potential to improve diagnostic accuracy and decrease costs relative to no second opinions or universal second opinions.

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.

Malpractice and Patient Safety Concerns.

OBJECTIVES: "Assurance behaviors," a type of defensive medicine, involve physicians' utilization of additional patient services to avoid adverse legal outcomes. We aim to compare the use of clinical behaviors (such as ordering additional tests, services, and consultations) due to malpractice concerns with the same behaviors due to patient safety concerns. METHODS: A national sample of dermatopathologists (n = 160) completed an online survey. RESULTS: Participants reported using one or more of five clinical behaviors due to concerns about medical malpractice (95%) and patient safety (99%). Self-reported use of clinical behaviors due to malpractice concerns and patient safety concerns was compared, including ordering additional immunohistochemistry/molecular tests (71% vs 90%, respectively, P < .0001), recommending additional surgical sampling (78% vs 91%, P < .0001), requesting additional slides (81% vs 95%, P < .0001), obtaining second reviews (78% vs 91%, P < .0001), and adding caveats into reports regarding lesion difficulty (85% vs 89%, P > .05). CONCLUSIONS: Dermatopathologists use many clinical behaviors both as assurance behaviors and due to patient safety concerns, with a higher proportion reporting patient safety concerns as a motivation for specific behaviors.

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.

Dermatopathologists' Experience With and Perceptions of Patient Online Access to Pathologic Test Result Reports.

Importance: Many patients presently have access to their pathologic test result reports via online patient portals, yet little is known about pathologists' perspective on this topic. Objective: To examine dermatopathologists' experience and perceptions of patient online access to pathology reports. Design, Setting, and Participants: A survey of 160 dermatopathologists currently practicing in the United States who are board certified and/or fellowship trained in dermatopathology was conducted between July 15, 2018, and September 23, 2019. Those who reported interpreting skin biopsies of melanocytic lesions within the previous year and expected to continue interpreting them for the next 2 years were included. Main Outcomes and Measures: Dermatopathologists' demographic and clinical characteristics, experiences with patient online access to pathologic test result reports, potential behaviors and reactions to patient online access to those reports, and effects on patients who read their pathologic test result reports online. Results: Of the 160 participating dermatopathologists from the 226 eligible for participation (71% response rate), 107 were men (67%); mean (SD) age was 49 (9.7) years (range, 34-77 years). Ninety-one participants (57%) reported that patients have contacted them directly about pathologic test reports they had written. Some participants noted that they would decrease their use of abbreviations and/or specialized terminology (57 [36%]), change the way they describe lesions suspicious for cancer (29 [18%]), and need specialized training in communicating with patients (39 [24%]) if patients were reading their reports. Most respondents perceived that patient understanding would increase (97 [61%]) and the quality of patient-physician communication would increase (98 [61%]) owing to the availability of online reports. Slightly higher proportions perceived increased patient worry (114 [71%]) and confusion (116 [73%]). However, on balance, most participants (114 [71%]) agreed that making pathologic test result reports available to patients online is a good idea. Conclusions and Relevance: Dermatopathologists in this survey study perceived both positive and negative consequences of patient online access to pathologic test result reports written by the respondents. Most participants believe that making pathologic test result reports available to patients online is a good idea; however, they also report concerns about patient worry and confusion increasing as a result. Further research regarding best practices and the effect on both patients and clinicians is warranted.

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 Second-Opinion Strategies for Diagnoses of Cutaneous Melanocytic Lesions.

Importance: Histopathologic criteria have limited diagnostic reliability for a range of cutaneous melanocytic lesions. Objective: To evaluate the association of second-opinion strategies by general pathologists and dermatopathologists with the overall reliability of diagnosis of difficult melanocytic lesions. Design, Setting, and Participants: This diagnostic study used samples from the Melanoma Pathology Study, which comprises 240 melanocytic lesion samples selected from a dermatopathology laboratory in Bellevue, Washington, and represents the full spectrum of lesions from common nevi to invasive melanoma. Five sets of 48 samples were evaluated independently by 187 US pathologists from July 15, 2013, through May 23, 2016. Data analysis was performed from April 2016 through November 2017. Main Outcomes and Measures: Accuracy of diagnosis, defined as concordance with an expert consensus diagnosis of 3 experienced pathologists, was assessed after applying 10 different second-opinion strategies. Results: Among the 187 US pathologists examining the 24 lesion samples, 113 were general pathologists (65 men [57.5%]; mean age at survey, 53.7 years [range, 33.0-79.0 years]) and 74 were dermatopathologists (49 men [66.2%]; mean age at survey, 46.4 years [range, 33.0-77.0 years]). Among the 8976 initial case interpretations, physicians desired second opinions for 3899 (43.4%), most often for interpretation of severely dysplastic nevi. The overall misclassification rate was highest when interpretations did not include second opinions and initial reviewers were all general pathologists lacking subspecialty training (52.8%; 95% CI, 51.3%-54.3%). When considering different second opinion strategies, the misclassification of melanocytic lesions was lowest when the first, second, and third consulting reviewers were subspecialty-trained dermatopathologists and when all lesions were subject to second opinions (36.7%; 95% CI, 33.1%-40.7%). When the second opinion strategies were compared with single interpretations without second opinions, the reductions in misclassification rates for some of the strategies were statistically significant, but none of the strategies eliminated diagnostic misclassification. Melanocytic lesions in the middle of the diagnostic spectrum had the highest misclassification rates (eg, moderately or severely dysplastic nevus, Spitz nevus, melanoma in situ, and pathologic stage [p]T1a invasive melanoma). Variability of in situ and thin invasive melanoma was relatively intractable to all examined strategies. Conclusions and Relevance: The results of this study suggest that second opinions rendered by dermatopathologists improve reliability of melanocytic lesion diagnosis. However, discordance among pathologists remained high.