Nora Azin Ali ^1* Jan Calissendorff ^1,2 Henrik Falhammar ^1,2

• ¹ Karolinska Institutet (KI), Solna, Sweden
• ² Department of Endocrinology, Metabolism and Diabetes, Karolinska University Hospital, Stockholm, Stockholm, Sweden

Purpose: The aim of the study was to investigate sex differences in presentation of pheochro-mocytomas and paragangliomas (PPGLs). Methods: This is a retrospective cohort study including 183 patients with confirmed PPGL (females n=100, pheochromocytoma n=156) between year 2005 and 2023, attending Depart-ment of Endocrinology, Karolinska University Hospital, Stockholm. The collected data included the mode of presentation, symptoms, biochemical, genetic and histopathological test results. Results: The mean age at surgery/diagnosis was 54.9±17.0 years. Sweating was more common in females compared to males (44% vs 23%, p=0.003), and also takotsubo syndrome (10% vs 0% p=0.002). Males, on the other hand, were more likely to experience pallor (16% vs 4%, p=0.009), and were more often diagnosed due to investigations of a suspected PPGL (31% vs 18%, p=0.039) although no difference was found in the classic triad (sweating, palpitations and headache). Left-sided pheochromocytoma was more common among males than females (48% vs 29%, p=0.009). No differences between sexes were found in biochemical, genetical or histo-pathological results, or presence of metastasis at diagnosis. Conclusions: The reported symptoms by patients with PPGL were generally similar between the sexes, except for pallor and sweating. Takotsubo syndrome was more common among fe-males. More males with PPGL were found based on suspicion than females. Further research into sex differences in various aspects of PPGL should be pursued. Keywords: pheochromocytoma, paraganglioma, adrenal medullary tumor, male, female, symp-toms, signs, diagnosis