IMPE Abstracts

Background: Pituitary gigantism is a rare endocrine disease characterized by unusually tall stature due to growth hormone (GH) excess as a result of a GH-secreting pituitary tumor or hyperplasia, which occurs before epiphyseal closure. Treatment includes surgery, medical treatment and radiotherapy (RT),

Objective: describe the clinical course of 9 patients with pituitary gigantism.

Materials and methods: retrospective, multicenter cohort study; including nine patients who met the criteria for pituitary gigantism: height >2 SDS than expected for age, sex and midparental height, associated with elevated IGF1 and unsuppressed GH; admitted to 3 Hospitals in Buenos Aires, Argentina between 2003 and 2022.

Results: eight males and 1 female were included, with a median age of 14 years-old (r: 2-32) and height of 183 cm (r: 101.5 - 230) at diagnosis. All except one patient presented tall stature, acral and facial features. First clinical manifestations were headache (n=6), visual disturbances (n=4) and tall stature (n=3). At diagnosis the mean IGF-1 was 5.28 SDS. Five patients harbored developed macroadenomas, 2 microadenomas, and 2 showed no pathological images on MRI. Seven patients underwent transsphenoidal surgery, 2 required subsequent reoperation. Three (2 micro and 1 macroadenoma) achieved remission. Due to disease persistence, 4 patients with macroadenomas recieved somatostatin receptor ligands (SRL) monotherapy, 2 combined with cabergoline (CAB). Three received RT and 4 developed hypopituitarism. Among patients without pathological image on MRI, there was one 3 year-old girl with McCune Albright syndrome, who started combined treatment with SRL and CAB; the other was a 32 year-old man referred due to a diabetic coma treated with Pegvisomant due to SRL resistance, who died at 44 due to poorly-controlled diabetes. Adenomas immunohistochemistry revealed 4 somatotropinomas, 2 co-secreted GH-PRL, and 1 mamosomatotropinoma. Genetic studies (AIP, MEN 1, PRKAR1A, GENAS1, Xq26.3 DUPLICATION) were performed in 6 patients: one positive for AIP and the remaining 5 negative. Biochemical control was achieved in 75% during long-term follow-up.

Conclusions: In our knowledge this is the largest argentine cohort study describing the clinical, genetic and therapeutic features of pituitary gigantism. Tall stature and neuro-ophthalmological symptoms were the most frequent manifestations at diagnosis. Genetic results were often negative. Transsphenoidal surgery was the gold-standard treatment, although additional drug therapy was usually required in patients with invasive tumors. Early diagnosis and treatment with a multidisciplinary team improve outcomes preventing GH associated comorbidities, and this is the key to control overgrowth and elevated final adult height.