**5. Conclusions**

New data on genetic, metabolic, and biochemical alterations of Pheos and Pgls allow us to look for genotype-phenotype correlations.

Depending on biochemical secretory characteristics, Pheos and Pgls can be divided into three different biochemical or secretory phenotypes: adrenergic, noradrenergic, and dopaminergic.

Depending on the affected gene and its activated intracellular signaling pathways, each tumor is clinically different.

Kinase signaling cluster genes are associated with tumors with an adrenergic phenotype consisting of epinephrine secretion. These tumors are mostly adrenal tumors, and they rarely develop metastatic disease, except for those associated with ATRX gene mutations.

Noradrenergic phenotype is suggestive of mutations in the pseudohypoxic pathway genes.

The dopaminergic phenotype consists of a sporadic group of neuroendocrine tumors that produce and secrete dopamine, and they are associated with SDHx mutations.

Regarding pediatric Pheos, the most affected genes are represented by VHL, followed by SDHB, SDHD, and NF1. Knowing the high incidence of germline mutations in the pediatric population, lifelong monitoring of secondary lesions is recommended.

All patients diagnosed with Pheos and Pgls should undergo genetic testing.

Genotype-biochemical phenotype correlations could help in genetic testing decision making.

Further studies are necessary for the complete identification of genotypespecific biochemical markers, which will be important in monitoring disease progression and determining treatment strategies. Furthermore, understanding of the metabolic and genetic basis of Pheos and Pgls will lead to the development of effective forms of therapy for these particular tumors.
