Surgical excision of the mediastinal tumor was performed. Gross pathological specimen show an encapsulated tan brown tissue. Microscopic analysis show an encapsulated lesion comprising of tumor cells in tight nests surrounded by fibrovasular stroma. The nuclei are mildly pleomorphic with granular chromatin. The cytoplasm is relatively abundant, granular and eosinophilic. No mitosis or area of necrosis. Immunohistochemistry show the tumor cells are reactive with chromogranin but not cytokeratin. S100 highlights sustentacular cells around the balls of cells. Overall features are consistent with paraganglioma.