Endocrine Abstracts

Aim: To describe the clinical course of an adolescent girl with gigantism.

Background and methods

In young persons with open epiphyses, overproduction of GH results in gigantism, with consequent longitudinal growth acceleration¹. Pituitary gigantism is extremely rare, and its cause in the majority of patients is a pituitary adenoma¹. Here, we present a 12, 5 years-old girl investigated for tall stature [183.5 cm (+4.24 SDS)].

Results: In the case reported here, the girl exhibited significant growth acceleration since she was 7 years-old, with coarsening of her facial features, and scoliosis of her thoracic spine. Her initial workup revealed a high insulin-like growth factor 1 (IGF-1), GH, and prolactin level, with no suppression of GH at the oral glucose tolerance test (OGTT); ACTH and cortisol values as well as thyroid function were within normal ranges. Magnetic resonance imaging (MRI) of the pituitary revealed a homogenous and diffusely enlarged pituitary gland, attributed to a pituitary macroadenoma (7.7 × 16 mm), which extended outside the pituitary gland. Whole exome sequencing analysis did not show any pathological findings. Thyroid ultrasound revealed cystic and solid nodules, with benign FNA. Firstly, she was treated with octreotide and cabergoline, followed by transsphenoidal surgical removal of the tumor. Postoperative levels of IGF-1 and prolactin decreased significantly; however GH levels at the OGTT test were partially suppressed, consistent with residual disease. Therefore, she underwent adjunctive radiation therapy. At 3-year follow-up, pituitary MRI findings represent an empty sella without significant functioning pituitary tissue, with remaining pituitary tumor mainly at the lateral sides of the sella. Her OGTT shows sufficient suppression of the GH level and her IGF-1 is in the lower side of the normal limit for her age, with stable clinical remission. At present, she is under octreotide treatment with no complaints, while cabergoline was stopped by the time prolactin levels were decreased.

Conclusion: This case demonstrated the difficulty of treating gigantism due to a GH/prolactin secreting pitutitary macroadenoma. At the same time, GH oversecretion is related to nodular thyroid disease, which requires careful evaluation with thyroid ultrasound. Genetic basis of the disease remains unclear in our patient.

References

1. Nagata Y, Inoshita N, Fukuhara N, Yamaguchi-Okada M & Nishioka H, et al. Growth hormone-producing pituitary adenomas in childhood and young adulthood: clinical features and outcomes. Pituitary 2018 211–9.