Zellballen pattern is found in histology of which of the following condition?

Ans. (b) Paraganglioma(Ref: Robbins 9/1135)The histologic pattern in pheochromocytoma shows tumor cells composed of clusters of polygonal to spindle shaped chromaffin cells or chief cells that are surrounded by supporting sustentacular cells, creating small nests or alveoli called zellballen. These are supplied by a rich vascular network