What is Signet ring cell melanoma?
• Signet ring cell melanoma: Two distinctive types of signet ring cells may be observed in this variant: (1) the usual type, composed of polygonal cells with accumulation of vimentin filaments in the cytoplasm, which displace the nucleus to the periphery of the cell and also confer a semilunar shape, and (2) a rarer variant, composed of cells with intracytoplasmic vacuoles and scalloped eccentric nuclei. In such situations, the neoplastic cells may resemble monovacuolated lipoblasts. Lipoblast-like cells are very unusual features of metastatic MMs and may be observed in metastatic deposits of signet ring and in balloon cell melanomas.
