English: Papillae vs pseudopapillae: True papillae are outgrowths of epithelium, surrounding fibrovascular cores of stroma and at least one blood vessel. In contrast, pseudopapillae (such as in solid pseudopapillary tumors) are nests of proliferating cells that eventually grow to become almost back-to-back, with cells in the centers of nests disintegrating, leaving rims of cells lining the periphery of each nest. Discohesive cells and some formations lacking central blood vessels are visual clues.