Carcinoid : Cytologic Atypia
The tumor cells in this pulmonary carcinoid are arranged in large anastomosing nests and trabeculae. A few large pleomorphic nuclei and multinucleated cells can be spotted in this image even at low magnification. Cytologic atypia, not accompanied by necrosis or increased mitotic activity, is sometimes seen in typical carcinoids. By itself, it is not sufficient to bump the diagnosis to atypical carcinoid.