A quantitative comparison between SOX10 and MART‐1 immunostaining to detect melanocytic hyperplasia in chronically sun‐damaged skin

Abstract

Histologic differentiation of melanoma in situ (MIS) from solar keratosis on chronically sun-damaged skin is challenging. The first-line immunostain is usually MART-1/Melan-A, which can exaggerate the epidermal melanocytes, causing a diagnostic pitfall for MIS. By comparing MART-1 and SOX10 immunostaining, we scored the percentage of epidermal melanocytes per 2-mm diameter fields in pigmented actinic keratosis (n = 16), lichenoid keratosis (n = 7), junctional melanocytic nevus (n = 6), keratosis with atypical melanocytic proliferation (n = 17) and MIS (n = 10). These cases represented an older population (68 years median age) and the head and neck (50%) was the most common anatomic site. MART-1 score was significantly higher than SOX10 (P value <.05) in solar keratoses, but showed no difference in detecting melanocytic proliferations, demonstrating their equal detection rate of melanocytes. The sensitivity of both MART-1 and SOX10 was 100%, while their specificities were 17% and 96%, respectively. These results show that SOX10 is more specific than MART-1 in distinguishing epidermal melanocytes on sun-damaged skin by avoiding overdiagnosis of melanoma.

Pigmented Actinic Keratosis: Case Report and Review of an Uncommon Actinic Keratosis Variant that can Mimic Melanoma

“…Initially, S100 was used. More recently, newer markers have been incorporated such as melanoma antigen recognized by T cells 1 (MART-1), microphthalmia-associated transcription factor (MiTF), and Sry-related HMG-BOX gene 10 (SOX-10) [14]. Similar to our patient, the atypical cells are negative for these melanocytic markers in lesions of pigmented actinic keratosis.…”

NCCN Guidelines® Insights: Melanoma: Cutaneous, Version 2.2021

“…Management of 2 subtypes of MIS-lentigo maligna (LM) and acral lentiginous type-present surgical challenges because of subclinical extension of tumor cells, location in anatomically constrained sites (eg, face, palms, soles), in addition to the presence of atypical/actinic melanocytic hyperplasia in the LM subtype (high-CSD melanoma) which often confounds histologic assessment of margin status. 88,[105][106][107][108][109][110][111][112][113][114][115][116][117] For this reason, surgery with complete circumferential peripheral and deep margin assessment (CCPDMA) has been studied in MIS to improve histologic clearance and decrease the chance of local recurrence (typically persistent disease-type, with in situ and/or radial growth phase). 88,89,109,111,112,115,[118][119][120][121][122][123][124][125][126][127][128][129][130][131] Mohs micrographic surgery (MMS) and staged excision with formalin-fixed, paraffin-embedded (ie, permanent) sections are types of CCPDMA, though these techniques have not yet been prospectively studied in comparison with conventional WE for MIS or invasive CM for local control.…”

Comparison of SOX-10, HMB-45, and Melan-A in Benign Melanocytic Lesions

“…Early melanoma in situ can be difficult to distinguish from lentigo senilis, particularly in sun-damaged skin, which can result in a significant delay in diagnosis. 1,2 Efforts to identify additional prognostic biomarkers in melanocytic lesions continue to be a challenge. Hematoxylin and eosin (H&E) staining in conjunction with immunohistochemistry has remained the gold standard for dermatopathologists to confirm their diagnoses.…”

“…SOX-10 is a nuclear transcription factor involved in the differentiation of neural crest cells to melanocytes. 2 Its nuclear pattern differentiates itself from the other commonly used melanocytic markers. It has been shown to be both a sensitive and specific marker in staining melanomas.…”