Revision of the Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis Classification Schema for Melanocytic Lesions

Abstract

ImportanceA 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.ObjectiveTo 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 ReviewPracticing 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.FindingsThe 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 RelevanceThe 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.

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

“…Finally, the MPATH-Dx schema was recently revised into an MPATH-Dx 2.0 version, whereby most moderate atypias do not require a re-excision. 13 As new data emerges 22 and the field evolves, the MPATH-Dx (and the educational tutorial) will need to be updated accordingly.…”

“…6 Over the past decade, the MPATH-Dx has been successfully used in research. 7 , 8 , 9 , 10 , 11 The International Melanoma Pathology Study Group has evaluated 12 and helped refine the MPATH-Dx 13 , the schema is included in dermatopathology textbooks 14 , 15 and mentioned in the World Health Organization Classification of Skin Tumours, 16 , 17 and interest of pathologists around the globe has been piqued. 18 US dermatopathologists have recognized the value of a standardized system for categorizing melanocytic skin lesions for patient management and research, and have reported willingness to embrace the MPATH-Dx concept in their own practices to improve communication and patient care.…”

Spitz Tumors and Melanoma in the Genomic Age: A Retrospective Look at Ackerman’s Conundrum

“…Like problematic cases, all Spitz tumors could be prognostically assessed for their inherent clinical risk, that is, the probability of an adverse event occurring [40,75,76]. According to the TMB of each individual neoplasm, in fact, all Spitz tumors carry some level of risk, including lesions diagnosed as "Spitz nevi", which also imply a risk, albeit very small [67,72,85]. The level of risk could be estimated as very low/minimal and clinically negligible, low, moderate, high or very high, and clinically relevant (Table 4).…”

BRAF Mutated and Morphologically Spitzoid Tumors, a Subgroup of Melanocytic Neoplasms Difficult to Distinguish From True Spitz Neoplasms

“…4 As a result of more routine utilization of genomics, it has become apparent that there is a spectrum of BRAF and NRAS mutated melanocytic neoplasms, ranging from benign to malignant, that can closely mimic Spitz neoplasms morphologically. 2 In this study, we were specifically interested in whether expert pathologists could distinguish between benign and intermediate-grade melanocytic neoplasms with spitzoid morphology and a BRAF activating point mutation, that is, tumors, in general, mapping to MPATH-Dx V2.0 class II 5 from comparable true Spitz neoplasms. To assess this, we invited expert melanoma pathologists from the International Melanoma Pathology Study Group to evaluate and diagnose a series of 54 cases consisting of both BRAF-mutated nevi/tumors with spitzoid features (BRAF mutated and morphologically spitzoid [BAMS] nevi/tumors) and true fusion or HRAS mutated Spitz tumors (STs).…”