High blood pressure can damage multiple organs, particularly tissues of the cardiovascular system, brain and kidneys. If left untreated, high blood pressure associated with pheochromocytomas may result in a number of critical conditions, including:

  • Heart disease
  • Stroke
  • Kidney failure
  • Acute respiratory distress
  • Damage to nerves of the eye

Cancerous (malignant) tumors

Rarely, a pheochromocytoma is cancerous (malignant), and the cancerous cells spread to other parts of the body (metastasize). Cancerous cells from a pheochromocytoma or paraganglioma most often migrate to the lymph system, bones, liver or lungs.

Source- MayoClinic.org