No. Pheos are not contagious. Pheochromocytomas develop in the chromafin cells in the center of the adrenal gland (adrenal medulla). Nodules found outside of the medulla are known as paragangliomas that may or may not secrete hormones. Approximately 60% of pheos and Paras are hereditary. The remaining 40% are sporadic (no known genetic connection).