An interesting case of melanoma with divergent differentiation aberrantly expressing calretinin stain

Abstract

Metaplastic melanoma or melanoma with divergent differentiation is a rare variant of melanoma with a wide spectrum of mesodermal and ectodermal differentiation. This is a case of metaplastic melanoma with aberrant expression for calretinin stain in the chondroid component and malignant cells adjacent to it. The finding of calretinin positivity in melanoma could be useful in diagnosing metastatic metaplastic melanoma. The awareness of the possibility of aberrant calretinin positivity in metaplastic melanoma with chondroid differentiation is critical to avoid a potential pitfall in misdiagnosing metaplastic melanoma as sarcoma or mesothelioma.