<prompt> Zellballen pattern on histopathology is observed in?-GISTAstrocytornaCarotid body tumorRetinoblastoma  <response>: Zellballen pattern on histopathology is observed in Paraganglioma or Carotid body tumors. Zellenbalen- composed to nests of polygonal chief cells. Robbins basic pathology. 7th edition. page no. 789. 