6790 High IGF-1: What Else Could It Be?

Abstract Disclosure: A. Pinson-Hilkemeyer: None. L. Ghalib: None. A 28-year-old transgender male was referred to the pituitary clinic to evaluate an incidentally found small pituitary cyst. The initial MRI was ordered as part of a workup of recurrent headaches and possible Multiple Sclerosis (MS). He has been on a stable dose of testosterone cypionate 120mg every two weeks since 2020. The pituitary endocrine workup showed an elevated insulin like growth factor-1 (IGF-1) at 385.1 ng/ml (Reference range 96 – 262 ng/ml), however further hormonal workup was unremarkable with the most recent testosterone level of 309 ng/mL. He did not have any acromegalic features on examination. He underwent growth hormone suppression testing with an oral glucose tolerance test and GH suppressed to 0.12 ng/mL in 120 min, which was not consistent with the diagnosis of acromegaly. He has continued to have an elevated IGF-1 on repeat testing for 18 months.There are not many cases reporting elevated IGF-1 in the setting of hormonal therapy in the trans community. But it has been reported that administration of testosterone to hypogonadal and non-hypogonadal men can lead to increased levels of IGF-1. It has also been reported that cross-sex hormone treatment (HT) in the transgender population with either testosterone for a transgender male or estradiol for a transgender female has been related to increased levels of IGF-1 after starting treatment. It is well documented in patients with acromegaly, there are increased risk of cardiovascular and musculoskeletal disease, systemic inflammation, and insulin resistance. However, it is not well studied in the transgender population. More research is needed to determine the incidence and clinical significance of the isolated elevation in IGF-1 in this population. Also, if there is any benefit to screening transgender individuals who are on HT for elevated IGF-1 and if they are considered to be at increased risk for developing other potential side effects? Presentation: 6/3/2024