Assessment of Second-Opinion Strategies for Diagnoses of Cutaneous Melanocytic Lesions

Diagnostic discordance among histopathological reviewers of melanocytic lesions

BACKGROUND

Histopathological examination is adequate for the diagnosis of most cutaneous melanocytic neoplasms. However, there is a subset that is either difficult to definitively diagnose or would have diagnostic disagreement upon review by multiple dermatopathologists if a more exhaustive review was performed.

METHODS

Melanocytic lesions underwent an independent, blinded diagnostic histopathological review of hematoxylin and eosin-stained sections. Each lesion was reviewed by three to six dermatopathologists and categorized as benign, malignant, or unknown malignant potential (UMP). Diagnoses were grouped as concordant (all the same designation); opposing (received benign and malignant designations); majority (single designation with the highest number of diagnoses, no benign/malignant opposing designations); and non-definitive (equal number of non-opposing designations [i.e., benign/UMP or malignant/UMP]). Lesions with equivocal designations (concordant or majority UMP, opposing, majority, and non-definitive) were utilized in a patient treatment model of projected surgical treatment discrepancies.

RESULTS

In total, 3317 cases were reviewed, and 23.8% of lesions received equivocal diagnoses. Of these, 7.3% were majority benign, 4.8% were majority malignant, 2.7% were majority UMP, 0.5% were concordant UMP, 6.9% were opposing, and 1.6% were non-definitive. Patient treatment models of those with equivocal lesions (n = 788) revealed a potential of overall surgical treatment variations ranging from 18% to 72%, with the highest variation amongst lesions with opposing, non-definitive, or majority UMP (40%-72%) diagnoses.

CONCLUSION

Histopathologic review in this large cohort demonstrated substantial diagnostic variation, with 23.8% of cases receiving equivocal diagnoses. We identified diagnostic ambiguity even in lesions where a definitive diagnosis was previously rendered by a single real-world dermatopathologist. The combined clinical impact of diagnostic discordance or a final diagnosis of UMP is highlighted by high diagnosis-dependent treatment variation in the patient treatment model, which could be underreported in a real-world setting, where review by more than one to two dermatopathologists is relatively rare.

Second opinion machine learning for fast-track pathway assignment in hip and knee replacement surgery: the use of patient-reported outcome measures

BACKGROUND

The frequency of hip and knee arthroplasty surgeries has been rising steadily in recent decades. This trend is attributed to an aging population, leading to increased demands on healthcare systems. Fast Track (FT) surgical protocols, perioperative procedures designed to expedite patient recovery and early mobilization, have demonstrated efficacy in reducing hospital stays, convalescence periods, and associated costs. However, the criteria for selecting patients for FT procedures have not fully capitalized on the available patient data, including patient-reported outcome measures (PROMs).

METHODS

Our study focused on developing machine learning (ML) models to support decision making in assigning patients to FT procedures, utilizing data from patients' self-reported health status. These models are specifically designed to predict the potential health status improvement in patients initially selected for FT. Our approach focused on techniques inspired by the concept of controllable AI. This includes eXplainable AI (XAI), which aims to make the model's recommendations comprehensible to clinicians, and cautious prediction, a method used to alert clinicians about potential control losses, thereby enhancing the models' trustworthiness and reliability.

RESULTS

Our models were trained and tested using a dataset comprising 899 records from individual patients admitted to the FT program at IRCCS Ospedale Galeazzi-Sant'Ambrogio. After training and selecting hyper-parameters, the models were assessed using a separate internal test set. The interpretable models demonstrated performance on par or even better than the most effective 'black-box' model (Random Forest). These models achieved sensitivity, specificity, and positive predictive value (PPV) exceeding 70%, with an area under the curve (AUC) greater than 80%. The cautious prediction models exhibited enhanced performance while maintaining satisfactory coverage (over 50%). Further, when externally validated on a separate cohort from the same hospital-comprising patients from a subsequent time period-the models showed no pragmatically notable decline in performance.

CONCLUSIONS

Our results demonstrate the effectiveness of utilizing PROMs as basis to develop ML models for planning assignments to FT procedures. Notably, the application of controllable AI techniques, particularly those based on XAI and cautious prediction, emerges as a promising approach. These techniques provide reliable and interpretable support, essential for informed decision-making in clinical processes.

A clinical impact study of dermatologists' use of diagnostic gene expression profile testing to guide patient management

Aim: Cutaneous melanocytic neoplasms with diagnostic and/or clinical ambiguity pose patient management challenges. Methods: Six randomized case scenarios with diagnostic/clinical uncertainty were described with/without a benign or malignant diagnostic gene expression profile (GEP) result. Results: Clinical impact was assessed by reporting the mean increase/decrease of management changes normalized to baseline (n = 32 dermatologists). Benign GEP results prompted clinicians to decrease surgical margins (84.2%). Malignant GEP results escalated surgical excision recommendations (100%). A majority (72.2%) reduced and nearly all (98.9%) increased follow-up frequency for benign or malignant GEP results, respectively. There was an overall increase in management plan confidence with GEP results. Conclusion: Diagnostic GEP tests help guide clinical decision-making in a variety of diagnostically ambiguous or clinicopathologically discordant scenarios.

Gender differences in pediatric and adolescent melanoma: A retrospective analysis of 4645 cases

BACKGROUND

There is paucity of data on how gender impacts melanoma prognosis in pediatric and adolescent patients.

OBJECTIVES

This study explores gender differences in presentation and survival among pediatric and adolescent patients with melanoma.

METHODS

The National Cancer Database 2004-2018 was queried for cases of primary invasive cutaneous melanoma in pediatric and adolescent patients (birth to 21 years) for a retrospective cohort study.

RESULTS

Of the 4645 cases, 63.4% were female. Median Breslow depth was 1.05 mm for males (interquartile range 0.50-2.31) and 0.80 mm for females (interquartile range 0.40-1.67; P < .001). Trunk was the most common primary site for females (34.3%) and males (32.9%). More females than males were diagnosed with stage I disease (67.8% vs 53.6%). Males had higher rates of regional lymph node positivity (27.9% vs 18.1%; P < .001) and ulceration (17.1% vs 11.4%; P < .001). Five-year overall survival was 95.9% for females and 92.0% for males (P < .001). After adjusting for confounders, male gender independently increased mortality risk (reference: females; adjusted hazard ratio 1.57; 95% confidence interval 1.32-1.86).

LIMITATIONS

Retrospective study.

CONCLUSION

Males exhibited more aggressive pathologic features including greater Breslow thickness and higher ulceration and lymph node positivity rates. Male gender independently increased mortality risk.

The Implications of a Dermatopathologist's Report on Melanoma Diagnosis and Treatment

An accurate and comprehensive histopathology report is essential for cutaneous melanoma management, providing critical information for accurate staging and risk estimation and determining the optimal surgical approach. In many institutions, a review of melanoma biopsy specimens by expert dermatopathologists is considered a necessary step. This study examined these reviews to determine the critical primary histopathology Breslow score in which a histopathology review would be most beneficial. Histopathology reports of patients referred to our institute between January 2011 and September 2019 were compared with our in-house review conducted by an expert dermatopathologist. The review focused on assessing fundamental histologic and clinical prognostic features. A total of 177 specimens underwent histopathology review. Significant changes in the Breslow index were identified in 103 cases (58.2%). Notably, in many of these cases (73.2%), the revised Breslow was higher than the initially reported score. Consequently, the T-stage was modified in 51 lesions (28.8%). Substantial discordance rates were observed in Tis (57%), T1b (59%), T3a (67%) and T4a (50%) classifications. The revised histopathology reports resulted in alterations to the surgical plan in 15.3% of the cases. These findings emphasize the importance of having all routine pathologies of pigmented lesions referred to a dedicated cancer center and reviewed by an experienced dermatopathologist. This recommendation is particularly crucial in instances where the histopathology review can potentially alter the diagnosis and treatment plan, such as in melanoma in situ and thinner melanomas measuring 0.6-2.2 mm in thickness. Our study highlights the significant impact of histopathology reviews in cutaneous melanoma cases. The observed changes in Breslow scores and subsequent modifications in T-stage classification underline the need for thorough evaluation by an expert dermatopathologist, especially in cases of melanoma in situ and thin melanomas. Incorporating such reviews into routine practice within dedicated cancer centers can improve diagnostic accuracy and guide appropriate treatment decisions, ultimately leading to better patient outcomes.

Impact of second opinion pathology review in the diagnosis and management of atypical melanocytic lesions: A prospective study of the Italian Melanoma Intergroup (IMI) and EORTC Melanoma Group

BACKGROUND

The clinical value of an expert pathological review in patients with an atypical melanocytic lesion diagnosis remains unclear. Herein, we evaluate its impact in a prospective clinical study.

METHODS

Patients with newly diagnosed or suspected atypical melanocytic proliferations and challenging skin tumours were reviewed prospectively by a specialised dermatopathologist through the nationwide 'Second Opinion Platform' of the Italian Melanoma Intergroup (IMI) network. The primary aim was the rate of major discrepancies that impacted patient management. Major discrepancies in diagnosis between referral and specialised review were blindly re-analysed by a panel of European Organisation for Research and Treatment (EORTC) Melanoma pathologists.

RESULTS

The samples submitted to central review included 254 lesions from 230 patients. The most frequent referral diagnoses were atypical melanocytic nevi of different subtypes (74/254, 29.2%), invasive melanomas (61/254, 24.0%), atypical melanocytic proliferations (37/254, 14.6%), AST (21/254, 8.3%) and in situ melanomas (17/254, 6.7%). There was disagreement between referral diagnosis and expert review in 90/254 cases (35.4%). Most importantly, 60/90 (66.7%) were major discordances with a change to the patient's clinical management. Among the 90 discordant cases, the most frequent new diagnosis occurred in World Health Organisation (WHO) Pathway I, followed by WHO Pathway IV (64/90 and 12/90, respectively). In total, 51/60 cases with major discrepancies were blindly re-evaluated by EORTC Melanoma pathologists with a final interobserver agreement in 90% of cases.

CONCLUSION

The study highlights that a second opinion for atypical melanocytic lesions affects clinical management in a minor, but still significant, proportion of cases. A central expert review supports pathologists and clinicians to limit the risk of both over- and under-treatment.

Are Pathologists Self-Aware of Their Diagnostic Accuracy? Metacognition and the Diagnostic Process in Pathology

BACKGROUND

Metacognition is a cognitive process that involves self-awareness of thinking, understanding, and performance. This study assesses pathologists' metacognition by examining the association between their diagnostic accuracy and self-reported confidence levels while interpreting skin and breast biopsies.

DESIGN

We studied 187 pathologists from the Melanoma Pathology Study (M-Path) and 115 pathologists from the Breast Pathology Study (B-Path). We measured pathologists' metacognitive ability by examining the area under the curve (AUC), the area under each pathologist's receiver operating characteristic (ROC) curve summarizing the association between confidence and diagnostic accuracy. We investigated possible relationships between this AUC measure, referred to as metacognitive sensitivity, and pathologist attributes. We also assessed whether higher metacognitive sensitivity affected the association between diagnostic accuracy and a secondary diagnostic action such as requesting a second opinion.

RESULTS

We found no significant associations between pathologist clinical attributes and metacognitive AUC. However, we found that pathologists with higher AUC showed a stronger trend to request secondary diagnostic action for inaccurate diagnoses and not for accurate diagnoses compared with pathologists with lower AUC.

LIMITATIONS

Pathologists reported confidence in specific diagnostic terms, rather than the broader classes into which the diagnostic terms were later grouped to determine accuracy. In addition, while there is no gold standard for the correct diagnosis to determine the accuracy of pathologists' interpretations, our studies achieved a high-quality reference diagnosis by using the consensus diagnosis of 3 experienced pathologists.

CONCLUSIONS

Metacognition can affect clinical decisions. If pathologists have self-awareness that their diagnosis may be inaccurate, they can request additional tests or second opinions, providing the opportunity to correct inaccurate diagnoses.

HIGHLIGHTS

Metacognitive sensitivity varied across pathologists, with most showing higher sensitivity than expected by chance.None of the demographic or clinical characteristics we examined was significantly associated with metacognitive sensitivity.Pathologists with higher metacognitive sensitivity were more likely to request additional tests or second opinions for their inaccurate diagnoses.

The markers auxiliary in differential diagnosis of early melanomas and benign nevi sharing some similar features potentially leading to misdiagnosis - a review of immunohistochemical studies

Although most melanocytic skin lesions are correctly diagnosed, numerous studies have shown interobserver disagreement. This review analyzes 20 molecules as immunohistochemical markers for distinguishing dysplastic and/or Spitz nevi from early melanomas (in situ, Clark level I or II and/or Breslow thickness at most 1 mm). The detected presence and/or level of tested molecules was significantly different in early melanomas than in dysplastic and Spitz nevi for six and seven potential markers, respectively. The most promising results were obtained for 5-hydroxymethylcytosine, cyclooxygenase-2 and PReferentially expressed Antigen in MElanoma whose levels were different in dysplastic and Spitz nevi compared to early melanomas.

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.

Histologic Screening of Malignant Melanoma, Spitz, Dermal and Junctional Melanocytic Nevi Using a Deep Learning Model

OBJECTIVE

The integration of an artificial intelligence tool into pathologists' workflow may lead to a more accurate and timely diagnosis of melanocytic lesions, directly patient care. The objective of this study was to create and evaluate the performance of such a model in achieving clinical-grade diagnoses of Spitz nevi, dermal and junctional melanocytic nevi, and melanomas.

METHODS

We created a beginner-level training environment by teaching our algorithm to perform cytologic inferences on 136,216 manually annotated tiles of hematoxylin and eosin-stained slides consisting of unequivocal melanocytic nevi, Spitz nevi, and invasive melanoma cases. We sequentially trained and tested our network to provide a final diagnosis-classification on 39 cases in total. Positive predictive value (precision) and sensitivity (recall) were used to measure our performance.

RESULTS

The tile-classification algorithm predicted the 136,216 irrelevant, melanoma, melanocytic nevi, and Spitz nevi tiles at sensitivities of 96%, 93%, 94% and 73%, respectively. The final trained model was able to correctly classify and predict the correct diagnosis in 85.7% of unseen cases (n = 28), reporting at or near screening-level performances for precision and recall of melanoma (76.2%, 100.0%), melanocytic nevi (100.0%, 75.0%), and Spitz nevi (100.0%, 75.0%).

CONCLUSIONS

Our pilot study proves that convolutional networks trained on cellular morphology to classify melanocytic proliferations can be used as a powerful tool to assist pathologists in screening for melanoma versus other benign lesions.

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.

Recognizing Histopathological Simulators of Melanoma to Avoid Misdiagnosis

Melanocytic lesions have a wide morphological spectrum, ranging from benign nevi to malignant melanoma. In contrast to a diagnosis of a benign nevus, a diagnosis of melanoma could mean intensive treatment, lifetime monitoring, and a worse prognosis. Therefore, melanocytic tumors are notoriously challenging and associated with a high risk of litigation in surgical pathology. After describing the basic features of nevi and melanoma, this article describes the detailed clinical and histological features of those lesions that share many similar features with melanoma. The entities included are Spitz nevi and atypical Spitz tumors (AST), Reed nevus, dysplastic nevus, cellular blue nevus (CBN), deep penetrating nevus, combined nevus, recurrent nevus, irritated nevus, congenital pattern nevus, acral nevus, and nevi of special sites. Knowledge of these imitators can help pathologists distinguish between benign and malignant cases and avoid misdiagnosis.

Reforms, Errors, and Dermatopathology Malpractice: Then and Now: A Comprehensive Retrospective

Medical malpractice occurs when a hospital, doctor, or other health care professional, through a negligent act or omission, causes an injury to a patient. The negligence might be the result of errors in diagnosis, treatment, aftercare, or health management. To be considered medical malpractice under the law, the claim must violate the standard of care, the injury must be caused by the negligence and, last but most certainly not least, the injury must result in significant damages. This review is an overview of medicolegal issues specific to the practice of Dermatopathology with the caveat that most are likely pertinent to other specialties of pathology as well. The safety of patients remains the priority in pathology as it does in any medical undertaking, and this is no different in the practice of Dermatopathology. The review is broadly divided in 2 parts-we begin with an overview of tort reforms, advocated by physicians to reduce costs associated with malpractice defense. In the second part we address practical issues specific to the practice of pathology and dermatopathology. These include among others, errors-related to the biopsy type, inadequacy of clinical information regarding the lesion that is biopsied, role of interstate dermatopathology as well as examples of select entities commonly misdiagnosed in dermatopathology. In the last decade, artificial intelligence (AI) has moved to the forefront of technology. While research into the uses of AI in pathology is promising, the use of AI in diagnostic practice is still somewhat uncommon. Given that AI is not fully integrated routinely as a diagnostic adjunct, its' impact on pathology-specific medicolegal issues cannot, as yet at least, be defined. Restriction of medical malpractice is of particular relevance in the COVID-19 era, a period that is anything but normal. The response of states with specific pandemic-related guidelines is addressed with the caveat that this particular issue is only covered in select states. Furthermore, given that the COVID pandemic is only a year old, while it does not appear to have had an immediate impact on pathology-specific medicolegal matters, it is possible that the role of COVID on this issue, if any at all, will and can only be fully defined a few years down the line.

Histopathologic and Molecular Diagnosis of Melanoma

Conventional histopathology is the primary means of melanoma diagnosis. Both architectural and cytologic features aid in discrimination of melanocytic nevi from melanoma. Communication between the clinician and pathologist regarding the history, examination, differential diagnosis, prior biopsy findings, method of sampling, and specimen orientation is critical to an accurate diagnosis. A melanoma pathology report includes multiple prognostic indicators to guide surgical and medical management. In challenging cases, immunohistochemistry and molecular diagnostics may be of benefit.

Molecular Markers and Targets in Melanoma

Melanoma develops as a result of several genetic alterations, with UV radiation often acting as a mutagenic risk factor. Deep knowledge of the molecular signaling pathways of different types of melanoma allows better characterization and provides tools for the development of therapies based on the intervention of signals promoted by these cascades. The latest World Health Organization classification acknowledged the specific genetic drivers leading to melanoma and classifies melanocytic lesions into nine distinct categories according to the associate cumulative sun damage (CSD), which correlates with the molecular alterations of tumors. The largest groups are melanomas associated with low-CSD or superficial spreading melanomas, characterized by frequent presentation of the BRAFV600 mutation. High-CSD melanomas include lentigo maligna type and desmoplastic melanomas, which often have a high mutation burden and can harbor NRAS, BRAFnon-V600E, or NF1 mutations. Non-CSD-associated melanomas encompass acral and mucosal melanomas that usually do not show BRAF, NRAS, or NF1 mutations (triple wild-type), but in a subset may have KIT or SF3B1 mutations. To improve survival, these driver alterations can be treated with targeted therapy achieving significant antitumor activity. In recent years, relevant improvement in the prognosis and survival of patients with melanoma has been achieved, since the introduction of BRAF/MEK tyrosine kinase inhibitors and immune checkpoint inhibitors. In this review, we describe the current knowledge of molecular pathways and discuss current and potential therapeutic targets in melanoma, focusing on their clinical relevance of development.

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.

A Clinicopathological Analysis of Melanocytic Nevi: A Retrospective Series

Purpose: Melanocytic nevi are common cutaneous lesions. This study aimed to demonstrate the concordance and discordance between clinical and histopathological diagnoses of melanocytic nevi and the importance of histological evaluation in differentiating malignant lesions from diseases with similar clinical manifestations.

Patients and Methods: We studied 4,561 consecutive patients with a clinical diagnosis of melanocytic nevi from 2014 to 2019. We compared the clinical diagnosis with the histopathological diagnosis to establish a histopathological concordance rate and then investigated the effects of clinical characteristics and the reasons for removal on misclassification.

Results: Among 4,561 patients who were clinically diagnosed with melanocytic nevi, the overall histopathological concordance rate was 82.11% (3,745 of 4,561 patients), while the histopathological discordance rate was 17.89% (816 of 4,561 patients). The histopathological concordance included 90.25% common acquired melanocytic nevi (3,380 of 3,745 patients) and 9.75% other benign melanocytic neoplasms (365 of 3,745 patients). The most common diagnostic change was to seborrheic keratosis (n = 470, 10.30%), followed by basal cell carcinoma (n = 64, 1.40%), vascular tumor (n = 53, 1.16%), fibroma (n = 43, 0.94%), epidermoid cyst (n = 34, 0.75%), wart (n = 30, 0.66%), melanoma (n = 24, 0.53%), Bowen's disease (n = 16, 0.35%), squamous cell carcinoma (n = 4, 0.09%), keratoacanthoma (n = 2, 0.04%), and other neoplasms (n = 76, 1.67%). Male sex, old age, location of the lesion, and the reasons for removal have a potential effect on misclassification. The percentages of misclassified lesions on the trunk and limbs and the perineum and buttocks were higher than those in lesions without a change in diagnosis. Importantly, locations of lesions on the head and neck were significantly related to a change in diagnosis to non-melanoma skin cancer, while locations on the hands and feet were significantly related to a change in diagnosis to melanoma. In addition to a typical clinical features, removal due to lesion changes or repeated stimulation was significantly associated with a change in diagnosis to melanoma.

Conclusions: Our study emphasizes the clinical differential diagnosis of melanocytic nevi, especially the possibility of malignant tumors. The occurrence of clinical features associated with clinicopathological discordance should raise the clinical suspect and be carefully differentiated from malignant tumors.

The WHO 2018 Classification of Cutaneous Melanocytic Neoplasms: Suggestions From Routine Practice

The "multidimensional" World Health Organization (WHO) classification 2018 of melanocytic tumors encompasses nine melanoma pathways (seven of which for cutaneous melanoma) according to a progression model in which morphologically intermediate melanocytic tumors are cosidered as simulators and/or precursors to melanoma. These "intermediates" can be subclassified into: i) a "classical" subgroup (superficial/thin compound: dysplastic nevus), which is placed within the morphologic and molecular progression spectrum of classical (Clark's and McGovern's) melanoma subtypes (superficial spreading and, possibly, nodular); and ii) a "non-classical" subgroup (thick compound/dermal: "melanocytomas") whose genetic pathways diverge from classical melanoma subtypes. Such a progression model is aimed at giving a conceptual framework for a histopathological classification; however, routine clinicopathological practice strongly suggests that most melanomas arise de novo and that the vast majority of nevi are clinically stable or even involuting over time. Clinicopathological correlation can help identify some severely atypical but benign tumors (e.g.: sclerosing nevus with pseudomelanomatous features) as well as some deceptively bland melanomas (e.g.: lentiginous melanoma; nested melanoma), thereby addressing some ambiguous cases to a correct clinical management. The recently available adjuvant therapy regimens for melanoma raise the problem of a careful distinction between severely atypical (high grade) melanocytoma and "classical" melanoma: conventional morphology can guide an algorithmic approach based on an antibody panel (anti-mutated BRAF, BAP1, PRAME, ALK, TRKA, MET, HRAS-WT, ROS; beta catenin; R1alpha; p16; HMB45; Ki67), a first-line molecular study (identification of hot spot mutations of BRAF and NRAS) and an advanced molecular study (sequencing of NF1, KIT, BRAF, MAP2K1, GNAQ, GNA11, PLCB4, CYSLTR2, HRAS; fusions studies of BRAF, RET, MAP3K8, PRKCA); as a final step, next-generation sequencing can identify melanocytic tumors with rare genetic signatures and melanocytic tumors with a high tumor mutation burden which should be definitely ascribed to the category of classical melanoma with the respective therapeutic options.

The Need for Alternatives to Liver Biopsies: Non-Invasive Analytics and Diagnostics

Histology remains essential for the diagnosis and management of many disorders affecting the liver. However, the biopsy procedure itself is associated with a low risk of harm to the patient and cost to the health services; samples may not be adequate and are subject to sampling variation. Furthermore, interpretation often depends on the skill of the pathologist. Increasingly, new techniques are becoming available that are altering the indications for liver biopsy. Many diseases of the liver can be diagnosed and managed using serological and radiological techniques; the degree of fibrosis and fat can often be assessed by serological or imaging techniques and the nature of space occupying lesions defined by serology, imaging and use of liquid biopsy. However, these techniques, too, are subject to limitations: sensitivity and specificity is not always adequate for diagnosis or management; some techniques are expensive and often also require expert interpretation. Although there may be less need for liver biopsy today, histology remains the gold standard as well as an essential tool for the diagnosis and management of many conditions, especially where there are multiple pathologies, or where a diagnosis cannot or has not been made by alternative approaches. Until less invasive techniques become more reliable and accessible, liver histology will remain a key investigation.

Molecular Biomarkers for Melanoma Screening, Diagnosis and Prognosis: Current State and Future Prospects

Despite significant progress in the development of treatment options, melanoma remains a leading cause of death due to skin cancer. Advances in our understanding of the genetic, transcriptomic, and morphologic spectrum of benign and malignant melanocytic neoplasia have enabled the field to propose biomarkers with potential diagnostic, prognostic, and predictive value. While these proposed biomarkers have the potential to improve clinical decision making at multiple critical intervention points, most remain unvalidated. Clinical validation of even the most commonly assessed biomarkers will require substantial resources, including limited clinical specimens. It is therefore important to consider the properties that constitute a relevant and clinically-useful biomarker-based test prior to engaging in large validation studies. In this review article we adapt an established framework for determining minimally-useful biomarker test characteristics, and apply this framework to a discussion of currently used and proposed biomarkers designed to aid melanoma detection, staging, prognosis, and choice of treatment.

Estimating the potential impact of interventions to reduce over-calling and under-calling of melanoma

BACKGROUND

Pathologists sometimes disagree over the histopathologic diagnosis of melanoma. 'Over-calling' and 'under-calling' of melanoma may harm individuals and healthcare systems.

OBJECTIVES

To estimate the extent of 'over-calling' and 'under-calling' of melanoma for a population undergoing one excision per person and to model the impact of potential solutions.

METHODS

In this epidemiological modelling study, we undertook simulations using published data on the prevalence and diagnostic accuracy of melanocytic histopathology in the U.S.

POPULATION

We simulated results for 10 000 patients each undergoing excision of one melanocytic lesion, interpreted by one community pathologist. We repeated the simulation using a hypothetical intervention that improves diagnostic agreement between community pathologist and a specialist dermatopathologist. We then evaluated four scenarios for how melanocytic lesions judged to be neither clearly benign (post-test probability of melanoma < 5%), nor clearly malignant (post-test probability of melanoma > 90%) might be handled, before sending for expert dermatopathologist review to decide the final diagnosis. These were (1) no intervention before expert review, (2) formal second community pathologist review, (3) intervention to increase diagnostic agreement and (4) both the intervention and formal second community pathologist review. The main outcomes were the probability of 'over-calling' and 'under-calling' melanoma, and number of lesions requiring expert referral for each scenario.

RESULTS

For 10 000 individuals undergoing excision of one melanocytic lesion, interpreted by a community pathologist, a hypothetical intervention to improve histopathology agreement reduced the number of benign lesions 'over-called' as melanoma from 308 to 164 and the number of melanomas 'under-called' from 289 to 240. If all uncertain diagnoses were sent for expert review, the number of referrals would decrease from 1500 to 737 cases if formal second community pathologist review was used, and to 701 cases if the hypothetical intervention was additionally used.

CONCLUSIONS

Interventions to improve histopathology agreement may reduce melanoma 'over-calling' and 'under-calling'.

Impact of second-opinion dermatopathology reviews on surgical management of malignant neoplasms

BACKGROUND

Second-opinion review is linked to error reduction and treatment changes in anatomic pathology.

OBJECTIVE

We sought to establish the rate of diagnostic discrepancy identified by second-opinion dermatopathologic review and the effect on surgical treatment.

METHODS

Cases referred for treatment of a malignant neoplasm diagnosed by an outside pathologist were reviewed. The external and internal second-opinion dermatopathologic reports were compared. Discordance in diagnosis, subtype, and treatment change owing to second-opinion review was recorded. The referring pathologist's level of dermatopathologic training was also documented.

RESULTS

A total of 358 cases were included. Dermatopathologic second-opinion diagnosis was discordant with the outside diagnosis in 37 of 358 cases (10.3%). In 32 of 358 cases (8.9%), second-opinion review resulted in a change in treatment, with 28 of 32 (87.5%) of these changes resulting in cancelled surgery. Dermatologists without dermatopathologic fellowship training had the highest rate of discordant diagnoses compared with pathologists and dermatopathologists.

LIMITATIONS

This was a retrospective study at a tertiary care facility.

CONCLUSION

Second-opinion dermatopathologic review is associated with identification of discordant diagnoses and a substantial influence on treatment, with both cancellation of surgery and augmented management. Secondary pathologic review should be considered in high-volume surgical practices.

ESP, EORTC, and EURACAN Expert Opinion: practical recommendations for the pathological diagnosis and clinical management of intermediate melanocytic tumors and rare related melanoma variants

The recent WHO classification of skin tumors has underscored the importance of acknowledging intermediate grade melanocytic proliferations. A multistep acquisition of oncogenic events drives the progressive transformation of nevi into melanomas. The various pathways described are modulated by the initial oncogenic drivers that define the common, blue, and Spitz nevi groups. Intermediate lesions are most often the result of a clonal evolution within such nevi. Based on this established classification, we have suggested for each pathway a practical diagnostic approach, benefiting from the recently developed molecular tools, both in the setting of general pathology labs and expert centers. Moreover, recommendations regarding the re-excision and clinical follow-up are given to support decision-making in multidisciplinary tumor boards.

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.

Artificial Intelligence in Dermatology: A Primer

Artificial intelligence is becoming increasingly important in dermatology, with studies reporting accuracy matching or exceeding dermatologists for the diagnosis of skin lesions from clinical and dermoscopic images. However, real-world clinical validation is currently lacking. We review dermatological applications of deep learning, the leading artificial intelligence technology for image analysis, and discuss its current capabilities, potential failure modes, and challenges surrounding performance assessment and interpretability. We address the following three primary applications: (i) teledermatology, including triage for referral to dermatologists; (ii) augmenting clinical assessment during face-to-face visits; and (iii) dermatopathology. We discuss equity and ethical issues related to future clinical adoption and recommend specific standardization of metrics for reporting model performance.