Variability in the Histopathological Diagnosis of Nonmelanocytic Lesions Excised to Exclude Melanoma

Abstract

Introduction. The differential diagnosis of lesions excised to exclude melanoma include a variety of benign and malignant melanocytic and non-melanocytic lesions.
 Objectives. We examined the variability between pathologists in diagnosing non-melanocytic lesions.
 Methods. As part of a larger study prospectively examining the diagnosis of lesions excised to exclude melanoma in 198 patients at a primary care skin cancer clinic in Newcastle, Australia, we compared diagnosis made by 5 experienced dermatopathologists, of 44 non-melanocytic lesions in 44 patients aged 22-90.
 Results. Forty-four lesions (out of 217 in total) were non-melanocytic. Among the 5 pathologists who examined each case there was marked variability in the terminology used to diagnose each case. The most common variability was found between seborrheic keratosis, large cell acanthoma, solar lentigo, and lichenoid keratosis. The diagnosis made by the majority of the pathologists was deemed to be the reference diagnosis. Versus majority diagnosis, 4% of benign lesions were considered malignant, and 7% of malignant diagnoses were considered as benign.
 Conclusions. The different terminology adopted and lack of consensus in the diagnosis of these non-melanocytic lesions in this setting suggests that training AI systems using gold standards may be problematic. We propose a new management classification scheme called MOLEM (Management of Lesions Excised to exclude Melanoma) which expands the previously described MPATH-dx to include non-melanocytic lesions.

Assessment of a Diagnostic Classification System for Management of Lesions to Exclude Melanoma

“…Additionally, the data from this study shows that, in an Australian population, there is an over- and underdiagnosis of melanoma (5.3% and 18.1%, respectively) compared with the estimated population-based statistics reported by Elmore et al 3 using prevalence data from the US (8% overdiagnosed and 9% underdiagnosed). In this study and an associated report discussing only the nonmelanocytic lesions, 10 we have proposed MOLEM as a modification to the MPATH-Dx diagnostic and management schema for classification of melanocytic lesions. Although the MPATH-Dx has been shown to be more concordant for the diagnosis of melanocytic lesions, the current study also reveals that there is variation in the terminology and over- and underdiagnosis of malignancy for nonmelanocytic lesions, similar to melanocytic lesions.…”

“…In this current study, the previously reported MPATH-Dx schema 6 was extended into a 5-class scheme, which we have termed Management of Lesions to Exclude Melanoma (MOLEM), to include melanocytic and nonmelanocytic lesions in the categories. 10 In this study, pathologists have used the MOLEM reporting scheme and included a measure of diagnostic confidence. It is hypothesized that, in the study population, compared with the MPATH-Dx, there would be similar variability in diagnosing so-called borderline lesions (ie, class II in the proposed MOLEM schema) and that this would be associated with confidence in diagnosis.…”

“…In this current study, the previously reported MPATH-Dx schema 6 was extended into a 5-class scheme, which we have termed Management of Lesions to Exclude Melanoma (MOLEM), to include melanocytic and nonmelanocytic lesions in the categories. 10 …”

“…To our knowledge, there were no publications that examine the diagnostic variability in this entire spectrum of lesions excised to exclude melanoma at the time of writing. In this current study, the previously reported MPATH-Dx schema was extended into a 5-class scheme, which we have termed Management of Lesions to Exclude Melanoma (MOLEM), to include melanocytic and nonmelanocytic lesions in the categories …”

Human Papillomavirus-Associated Giant Clear Cell Acanthoma and Squamous Cell Carcinoma: A Rare Case Report and Literature Review

“…The relationship between HPV infection and skin cancer, particularly non-melanoma skin cancer (NMSC), such as squamous cell carcinoma (SCC) and keratoacanthoma, has been a subject of considerable scientific inquiry. The systematic review by Neagu et al (2022) included 2284 patients and found a significant presence of beta and gamma HPV subtypes in various forms of NMSC, suggesting the potential etiological role of HPV in keratinocyte skin cancers [22,[62][63][64]. Ramezani et al in 2020 conducted a meta-analysis specifically examining the association of β-HPV with SCC in immunosuppressed individuals, finding a high prevalence of β-HPVs in cutaneous SCC patients, which supports the hypothesis of β-HPV contributing to SCC development in those with compromised immune systems [65].…”