Hereditary paraganglioma pheochromocytoma syndrome (HPPS) includes a number of different genetic syndromes that all predispose individuals to develop paragangliomas (tumors that form from neuroendocrine tissue) and pheochromocytomas (similar tumors that form in the adrenal medulla). These tumors may or may not secrete hormones, and while the majority are benign (nonmalignant), a few of them can go on to become malignant (cancerous).
Patients with HPPS are also at an increased risk to develop the following, depending on the specific genetic syndrome:
- Renal cell carcinoma (a type of kidney cancer)
- Gastrointestinal stromal tumors
- Papillary thyroid carcinoma, pituitary adenomas and other neuroendocrine tumors
What are the causes?
HPPS is caused by genetic changes in a number of genes, which act as tumor suppressor genes:
- SDHx (SDHA, SDHB, SDHC, SDHD,SDHAF2)
A tumor suppressor gene, when working properly, encodes proteins that prevent the growth and development of tumors in the human body. The incidence of HPPS is estimated not known.
How is hereditary paraganglioma pheochromocytoma syndrome diagnosed?
HPPS can be diagnosed through genetic testing that is facilitated by a genetic counselor or genetics services provider.
Any patient diagnosed with a paraganglioma or a pheochromocytoma should be referred to genetic counseling or medical genetics in order to discuss genetic testing and be evaluated for HPPS.
Treatment and monitoring
Guidelines exist for the medical monitoring of children and adults with HPPS. This monitoring should start between ages 6 and 8 and often includes:
- Annual lab work (e.g., plasma metanephrines)
- Whole body MRI (skull to pelvis) once every two years
- Blood pressure checks at all clinical visits
- Physical exam (annually)