Interobserver agreement in the histopathological classification of desmoplastic melanomas

Published:January 16, 2023DOI:


      Desmoplastic melanoma is a subtype of melanoma characterised by amelanotic fusiform melanocytes dispersed in a collagenous stroma. Cell-poor and fibrous stroma-rich ‘pure’ variants have been distinguished from ‘mixed’ variants with areas of higher cell density and/or less desmoplastic stroma. This distinction is relevant because patients whose tumours display a pure phenotype have a lower risk for regional lymph node metastasis and distant recurrence. However, little is known about interobserver agreement among pathologists in the subclassification of desmoplastic melanoma. To address this issue, we conducted a study in which eleven dermatopathologists independently evaluated whole slide scanned images of excisions from 30 desmoplastic melanomas. The participating pathologists were asked to classify the tumours as pure or mixed. They were also asked to record the presence or absence of neurotropism and angiotropism. We found substantial interobserver agreement between the 11 dermatopathologists in the classification of tumours as pure versus mixed desmoplastic melanoma (kappa=0.64; p<0.0001). There was fair agreement between the 11 dermatopathologists in the evaluation of presence versus absence of neurotropism (kappa=0.26; p<0.0001), and slight agreement in the assessment of angiotropism (kappa=0.13; p<0.0001). The level of concordance in the subclassification of desmoplastic melanomas is encouraging for the acceptance of this prognostic parameter in the real-world practice of melanoma pathology.


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        • Busam K.J.
        • Mujumdar U.
        • Hummer A.J.
        • et al.
        Cutaneous desmoplastic melanoma: reappraisal of morphologic heterogeneity and prognostic factors.
        Am J Surg Pathol. 2004; 28: 1518-1525
        • Hawkins W.G.
        • Busam K.J.
        • Ben-Porat L.
        • et al.
        Desmoplastic melanoma: a pathologically and clinically distinct form of cutaneous melanoma.
        Ann Surg Oncol. 2005; 12: 207-213
        • McCarthy S.W.
        • Scolyer R.A.
        • Palmer A.A.
        Desmoplastic melanoma: a diagnostic trap for the unwary.
        Pathology. 2004; 36: 445-451
        • Murali R.
        • Shaw H.M.
        • Lai K.
        • et al.
        Prognostic factors in cutaneous desmoplastic melanoma: a study of 252 patients.
        Cancer. 2010; 116: 4130-4138
        • Wiesner T.
        • Kiuru M.
        • Scott S.N.
        • et al.
        NF1 mutations are common in desmoplastic melanoma.
        Am J Surg Pathol. 2015; 39: 1357-1362
        • Chen L.L.
        • Jaimes N.
        • Barker C.A.
        • et al.
        Desmoplastic melanoma: a review.
        J Am Acad Dermatol. 2013; 68: 825-833
        • Elder D.E.
        • Bastian B.C.
        • Cree I.A.
        • et al.
        The 2018 World Health Organization classification of cutaneous, mucosal, and uveal melanoma: detailed analysis of 9 distinct subtypes defined by their evolutionary pathway.
        Arch Pathol Lab Med. 2020; 144: 500-522
        • George E.
        • McClain S.E.
        • Slingluff C.L.
        • et al.
        Subclassification of desmoplastic melanoma: pure and mixed variants have significantly different capacities for lymph node metastasis.
        J Cutan Pathol. 2009; 36: 425-432
        • Laeijendecker A.E.
        • El Sharouni M.A.
        • Sigurdsson V.
        • et al.
        Desmoplastic melanoma: the role of pure and mixed subtype in sentinel lymph node biopsy and survival.
        Cancer Med. 2020; 9: 671-677
        • Pawlik T.M.
        • Ross M.I.
        • Prieto V.G.
        • et al.
        Assessment of the role of sentinel lymph node biopsy for primary cutaneous desmoplastic melanoma.
        Cancer. 2006; 106: 900-906
        • Shon W.
        • Frishberg D.P.
        • Gershenwald J.E.
        • et al.
        Protocol for the Examination of Excision Specimens From Patients With Melanoma of the Skin. Version: Nov 2021; cited Oct 2022.
        College of American Pathologists, Northfield, IL2021
        • Amin M.B.
        • Edge S.B.
        • Greene F.L.
        • et al.
        AJCC Cancer Staging Manual.
        Springer, New York2017
        • Barnhill R.
        • Dy K.
        • Lugassy C.
        Angiotropism in cutaneous melanoma: a prognostic factor strongly predicting risk for metastasis.
        J Invest Dermatol. 2002; 119: 705-706
        • Lugassy C.
        • Kleinman H.K.
        • Vermeulen P.B.
        • et al.
        Angiotropism, pericytic mimicry and extravascular migratory metastasis: an embryogenesis-derived program of tumour spread.
        Angiogenesis. 2020; 23: 27-41
        • Howard M.D.
        • Wee E.
        • Wolfe R.
        • et al.
        Differences between pure desmoplastic melanoma and superficial spreading melanoma in terms of survival, distribution and other clinicopathologic features.
        J Eur Acad Dermatol Venereol. 2019; 33: 1899-1906
        • Hughes T.M.
        • Williams G.J.
        • Gyorki D.E.
        • et al.
        Desmoplastic melanoma: a review of its pathology and clinical behaviour, and of management recommendations in published guidelines.
        J Eur Acad Dermatol Venereol. 2021; 35: 1290-1298
        • Nicolson N.G.
        • Han D.
        Desmoplastic melanoma.
        J Surg Oncol. 2019; 119: 208-215
        • Wood B.A.
        Desmoplastic melanoma: recent advances and persisting challenges.
        Pathology. 2013; 45: 453-463
        • Murali R.
        • Riedel E.R.
        • Busam K.J.
        • et al.
        Interobserver agreement of assessment of desmoplasia and neurotropism in melanoma. 101st annual meeting of the United States and Canadian Academy of Pathology (USCAP).
        Nature Publishing Group, Vancouver2012 (128–9A)
        • Barnhill R.L.
        • Busam K.J.
        • From L.
        • et al.
        Inter-observer concordance for the recognition of angiotropism in human melanoma.
        Pigment Cell Melanoma Res. 2011; 24: 582-583
        • Hanna M.G.
        • Reuter V.E.
        • Ardon O.
        • et al.
        Validation of a digital pathology system including remote review during the COVID-19 pandemic.
        Mod Pathol. 2020; 33: 2115-2127