Hereditary pheochromocytoma/parganglioma (HPP) syndromes are genetic diseases based on heterozygous mutations in an SDH gene, the MAX gene, or the TMEM127 gene. They are characterized by typically benign tumors originating in the neural crest. Extra-adrenal parasympathetic paragangliomas are frequently located in the area of the brain base, neck, and upper mediastinum and are generally not secretory. In contrast, sympathetic paragangliomas are usually located in the area of the lower mediastinum, abdomen, and pelvis and are hormone-producing. In addition, there is an association with gastrointestinal stromal tumors, renal cell tumors, and papillary thyroid adenomas.