(A) Fine-needle aspiration of thymoma showing predominately round to oval cells with moderate nuclear atypia in type AB thymoma. Note thick nuclear membranes and more prominent nucleoli. (B): High power view of type AB thymoma .Marked pleomorphism characterized these cells. Few lymphocytes are present.
Khaki et al. Diagnostic Pathology 2013 8:98 doi:10.1186/1746-1596-8-98