This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Pathology
Zellballen pattern on histopathology is observed in?- 
Select and explain. 
A. GIST, B. Astrocytorna, C. Carotid body tumor, D. Retinoblastoma
C: Carotid body tumor
Answer: C: Carotid body tumor 
Explanation: 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.