GROWTH RATE OF PARAGANGLIOMAS RELATED TO GERMLINE MUTATIONS OF THE SDHX GENES

Objective: The purpose was to determine the growth rate of succinate dehydrogenase subunit (SDHx) generelated paragangliomas based on computed tomography (CT) measurements. Methods: Twenty-seven patients with SDHx mutations who underwent subsequent CT examinations were enrolled in the study. Tumors were classified as head and neck (HNP), thoracic, or abdominal/pelvic paragangliomas (PGLs). The percentage volume increase and volume doubling time were estimated. Results: We analyzed 56 PGLs (21 with SDHD, 6 with SDHB mutations) in 27 patients (16 men, 11 women; mean age 37.7 years). The estimated median of the follow-up was 23 months. Twenty-two (39.3%) PGLs were located in the abdomen, 8 (14.3%) in the thorax, and 26 (46.4%) in the head and neck region. The median volume growth rate was estimated at 10.4% per year (interquartile range [IQR]: -1.3; 36.3). The volume doubling time was estimat-ed as 7.01 (2.24;+infinity) years. By tumor site, the estimated medians of the annual volume growth rates were 13.6% (IQR: 0.8 -30.4) for HNP, -6.06% (IQR: -1.79; 47.32) for thoracic PGLs, and 10.5% (IQR: -2.2; 44.6) for abdominal PGLs. The volume doubling time was 5.44 years (2.61; 87.0) for HNP, 11.8 years (1.79;+infinity) for thoracic PGLs, and 6.94 years (1,88;+infinity) for abdominal PGLs. There was no significant difference in the volume growth rate according to tumor location or initial size (P>. 7 and P = .07, respectively) or gene mutation type (SDHB vs. SDHD, P>. 8). Conclusion: PGLs related to SDHx mutations are slowly growing tumors. There were no correlations between tumor location, growth rate or initial size over a 23-month follow-up period.