Endocrine Abstracts

Introduction: Acromegaly is a rare, chronic endocrinopathy, that results from persistent hypersecretion of growth hormone (GH) and consequently of insulin-like growth factor 1 (IGF1). It is well known that GH excess has multisystemic effects throughout the body, but its interaction with the immune system has only been suggested in the last few decades. This prompted us to explore the frequency of autoimmune disorders in a retrospective acromegaly cohort.

Case description: We present 7 cases of acromegaly occurring in association with autoimmune diseases, other than autoimmune thyroiditis, that have been evaluated in our clinic between 2015 and 2022. Two patients were diagnosed with myasthenia gravis (one of them with concurrent Graves disease), two with vitiligo, one patient had antineutrophil cytoplasmic autoantibodies (ANCA) associated vasculitis, another patient displayed a case of severe rheumatoid arthritis, and one had generalized psoriasis. The mean age at diagnosis was 47.4 years for acromegaly and 47 for autoimmune diseases, with a 6:1 female to male ratio. The most common presenting symptom for acromegaly was headache (57%), whilst autoimmune disease manifestations varied from fatigue and unilateral eyelid twitching to thrombotic events and acute kidney failure. Six patients had pituitary macroadenomas and only one had a microadenoma with a mean IGF1 at diagnosis of 2.9× upper limit of normal. The diagnosis of acromegaly preceded the autoimmune disease confirmation in only three cases, with an estimated duration of 40.3 months; was concomitant with the diagnosis of one myasthenia gravis case and was established during the evolution of vitiligo and rheumatoid arthritis in the other three patients. Six patients (86%) underwent surgery (one of them had two interventions), 4 of which (57%) required additional therapy for biochemical control consisting of somatostatin analogues (SA, n=3) or combination therapy with SA and cabergoline (n=1). One patient was treatment-naïve. Complete biochemical control was achieved in 5 patients (71%) and 2 out of 3 patients had controlled acromegaly at the time of the autoimmune disease’s diagnosis. Complications of acromegaly or autoimmune diseases were identified in 86% of cases.

Conclusion: Despite the increasing evidence of the immunomodulatory actions of the GH/IGF1 axis, the reports on autoimmune diseases in acromegaly patients are sparse. Considering the increasing prevalence of this disorders and the debilitating complications of both acromegaly and autoimmune afflictions, the interaction between GH excess and a dysregulated immune system should be further analysed.