Immunohistochemical Expression of SATB2 in Malignant Melanomas

Accurate diagnosis of cancer of unknown primary (CUP) poses a significant daily challenge for pathologists, necessitating reliable immunohistochemical (IHC) markers. SATB2 is a transcription factor primarily expressed in colorectal neoplasms. This study investigates the IHC expression of SATB2 in malignant melanomas (MM). Using tissue microarrays (TMAs) from Aalborg University Hospital, Denmark, comprising 56 primary and 12 metastatic MMs, we evaluated SATB2 expression through H-scores. We found that 48% of MM cases expressed SATB2, predominantly with weak to moderate staining intensity. Although no significant difference was observed between primary and metastatic MMs, a higher median H-score was noted in metastatic lesions. The results highlight the potential diagnostic pitfall of SATB2 expression in MM and underline the need for careful interpretation.