Endocrine Abstracts

Introduction: Pituitary gigantism is a rare disorder characterized by growth hormone (GH) excess that occurs before epiphyseal growth plates fusion leading to rapid and excessive linear growth in childhood and very tall adult stature. It can be sporadic or coexist with genetic disorders such as FIPA, X-LAG, McCune-Albright, Carney complex, MEN 1 or 4, and Neurofibromatosis type 1.

Case report: We present a case of a 12 years old boy with no medical history, who presented in our clinic with pituitary incidentaloma detected on head CT scan for craniocerebral injury due to falling from the same level. The patient complained of intermittent headaches for about three years, tall stature, and large hands and feet (the mother reported an increase in the size of his shoes from 35 to 43). On physical examination, his height was 173.5 cm (+3 DS), with proportionate growth, height velocity approximately 10 cm in 10 months (reported by his mother), predictive target height 195 cm, parenteral target height 179 cm, body weight 52 kg (+1.13 DS), Tanner stage II. Laboratory tests showed elevated levels of serum age-adjusted and sex-adjusted IGF-1 (647 ng/ml, NV: 49-487 ng/ml) and failure of GH suppression during an oral glucose tolerance test (nadir GH 35 ng/ml). The other pituitary hormones were within normal limits. Bone age was normal for chronological age. MRI of the sellar region showed pituitary macroadenoma with dimensions of 23/19/11 mm with bilateral extension but no cavernous sinus invasion or optic chiasm involvement. Visual field evaluation was normal. He underwent transsphenoidal surgery and the histopathology report revealed positive immunohistochemistry for GH and prolactin, high Ki67 (25%) and positive p53. Three months after surgery, IGF-1 level normalized (390 ng/ml, NV: 49-487 ng/ml), GH secretion decreased significantly, but without suppression on OGTT (nadir GH 2.57 ng/ml), and no residual tumor was detected on MRI. There was no hypopituitarism after surgery. Treatment with first generation somatostatin analogues was initiated without response. In the absence of disease control, Pegvisomant was prescribed with favorable outcomes (IGF-1=160 ng/ml and growth stagnation), but after three months of treatment the patient presented elevated liver enzymes. The treatment with Pegvisomant was stopped and Pasireotide was initiated.

Conclusions: Pituitary gigantism is a rare disease, caused by a growth hormone secreting pituitary adenoma. Management of the disease represents a real challenge due to the lack of experience in children. Close follow-up is mandatory to prevent complications and improve survival rates.