Genetic Alterations and Clinical Features in Brazilian Patients With Pheochromocytomas and Paragangliomas

Pheochromocytomas and paragangliomas are tumors derived from chromaffin cells which result from mutations of at least six different genes as autosomal dominant disorders. We evaluated the existence of correlations between genetic alterations and clinical data in 16 patients with pheochromocytomas and/or paragangliomas. From 2007 to 2019, 13 patients with pheochromocytoma [3 men, medium age 39 years (14–61)] and 3 with paraganglioma [1 men, medium age 33 years (22–35)] were evaluated regarding the presence of genetic mutations and possible correlations between the latter and some clinical features. Besides the mutations, tumor size, symptoms and signs present by the time of the diagnosis were studied. Four patients had pathogenic mutations (SDHB deletion encompassing the promoter and exon 1, C98Y in the SDHB gene, N78S in the VHL gene, and C634R in the RET gene) and one subject had a V90M variant in the TMEM127 gene. Two patients did not present mutations and nine had nonpathogenic mutations. Regarding the presence of clinical features before treatment, there was a predominance of arterial hypertension (75.0%), while the prevalence of tachycardia, abdominal pain and headaches was respectively 12.5%, 12.5% and 6.25%. There was no significant difference between the age of patients with pathogenic mutations and that of the other patients (31.2 vs. 38.6 years, p= 0.3952). Moreover, there were no differences regarding the prevalence of pheochromocytoma (p= 0.2143) or clinical features (p: hypertension= 0.6346, tachycardia= 0.4583, abdominal pain= 0.5417, headaches= 0.6875), or tumor dimensions (p= 0.4578) when the two groups were compared. However, the prevalence of paragangliomas was higher in patients with pathogenic mutations (p= 0.0179). In patients with pheochromocytoma and paraganglioma, the absence of correlations between pathogenic mutations and clinical features increases the importance of the genetic studies in the determination of treatment and prognosis of these tumors. Furthermore, subjects with germline mutations associated with pheochromocytoma and paraganglioma should undergo lifelong clinical, biochemical and imaging surveillance and their families should receive genetic counseling.