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

Abstract

Purpose: Different immunohistochemical stains are used in dermatopathology to stain melanocytes and diagnose benign and malignant melanocytic lesions. Methods: SOX-10, HMB-45, and Melan-A immunohistochemical stains were used to assess 32 biopsy specimens with a histologic diagnosis of lentigo. The total number of melanocytes stained with each immunohistochemical stain was counted and an average count was obtained from two readings. Results: Analysis of the data revealed a significant difference in staining melanocytes between these three immunostains (p=0.0010, ANOVA). SOX-10 stained 0.195 more melanocytes than HMB-45 (p=0.0026). Similarly, Melan-A stained 0.195 more melanocytes than HMB-45 (p=0.0011). However, the difference between SOX-10 and Melan-A was not statistically significant (p=0.9810). Conclusion: SOX-10 and Melan-A immunostaining stain more melanocytes than HMB-45. No significant difference was noted between Melan-A and SOX-10.

The Importance of Immunohistochemistry in the Evaluation of Tumor Depth of Primary Cutaneous Melanoma

“…Melan-A/MART 1 is expressed in the endoplasmic reticulum and melanosomes, being considered a more sensitive marker than HMB-45. Although the staining of intensely pigmented keratinocytes is possible with Melan-A, but not with SOX10, Dass et al [ 45 ] did not find a significant difference between the staining with these two markers, this observation also being in accordance with the results of our study ( p > 0.05 for the values of the Breslow thickness measured based on SOX10 and Melan-A). Melan-A can aid in the identification of isolated tumoral melanocytes located in the dermis, which can upstage a previously diagnosed melanoma in situ with HE to an invasive lesion.…”

“…However, it can also stain benign melanocytes; therefore, the results must be cautiously interpreted in lesions associated with a nevus [ 44 ]. HMB-45 is a monoclonal antibody directed against PMEL17 (also referred to as gp100), with lower sensitivity, but better specificity for melanocytic differentiation [ 2 , 45 ]. It is useful in distinguishing between an invasive melanoma and a nevus, as it only stains the superficial nevic cells, due to loss of expression associated with maturation, and is regarded as the most appropriate marker for the evaluation of the junctional component [ 45 , 46 ].…”

“…HMB-45 is a monoclonal antibody directed against PMEL17 (also referred to as gp100), with lower sensitivity, but better specificity for melanocytic differentiation [ 2 , 45 ]. It is useful in distinguishing between an invasive melanoma and a nevus, as it only stains the superficial nevic cells, due to loss of expression associated with maturation, and is regarded as the most appropriate marker for the evaluation of the junctional component [ 45 , 46 ]. Although false positive results of HMB-45 have previously been reported, Ordóñez [ 47 ] found that HMB-45 is negative in tumors with glial, mesenchymal, lymphoid, or epithelial origin.…”

“…SOX10 exhibited higher specificity (96%) compared to Melan-A (17%) in evaluating epidermal malnocytes and consequently in avoiding overdiagnosis of melanoma in situ in sun-damaged skin [ 50 ]. Furthermore, the concomitant use of Melan-A with markers such as HMB-45 or S-100 was also recommended in order to avoid the misdiagnosing of “pseudomelanocytic” cells as melanoma cells [ 38 , 45 ].…”

A Disguising Fast-Growing Metachronous Melanoma and COVID-19

“…HMB-45 displays a greater specificity but lacks sensitivity. Melan-A is less specific than SOX-10 and may lead to false-positive results [14][15][16]. The presence of intra-nodal nevi does not influence survival, and these melanoma patients are generally regarded as SLNB-negative [10,17].…”