PRAME immunohistochemistry can distinguish melanocytic pseudonests of lichenoid reactions from melanoma in situ.
J Cutan Pathol
; 50(5): 450-454, 2023 May.
Article
em En
| MEDLINE
| ID: mdl-36789669
ABSTRACT
BACKGROUND:
Distinguishing melanocytic pseudonests encountered in lichenoid dermatoses or lichenoid keratoses from melanoma in situ (MIS) with brisk lichenoid inflammation can prove challenging.METHODS:
We designed a case-control study to evaluate the accuracy metrics of PRAME immunohistochemistry to distinguish melanocytic pseudonests in lichenoid dermatoses or keratoses from inflamed MIS. Immunostaining for PRAME was performed on paraffin-embedded formalin-fixed diagnostic tissue using a rabbit monoclonal antibody to PRAME (Abcam), with a 13200 dilution on a Leica Bond detection system.RESULTS:
Our search identified 21 cases of melanocytic pseudonests (n = 21, 46%) encountered in lichenoid dermatoses and 24 cases of inflamed MIS (n = 24, 53%). Each method of evaluating PRAME immunohistochemistry (PRAME+ clusters, PRAME % of melanocytes by four categories and PRAME+ melanocyte counts per linear mm of epidermal basal layer) showed statistically significant differences between the MIS and the pseudonest cohorts (respectively, p < 0.001; p < 0.001; and p < 0.001). Receiver operating characteristics analysis for PRAME+ melanocyte counts per linear mm of epidermal basal layer revealed an area under the curve of 0.9 ± 0.05 (95% confidence interval 0.9-1.0). When determining an optimal cut-off point for the best Youden index [sensitivity (%) + specificity (%) - 100], the cut-off of 1.0 PRAME+ melanocytes per linear mm showed a sensitivity of 79.2% and specificity of 85.7% (Youden index 0.65) to distinguish MIS from pseudonests.CONCLUSION:
PRAME immunohistochemistry may constitute an additional tool for this challenging differential diagnosis.Palavras-chave
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Assunto principal:
Neoplasias Cutâneas
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Imuno-Histoquímica
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Erupções Liquenoides
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Ceratose Actínica
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Melanoma
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article