Gigantism caused by growth hormone secreting pituitary adenoma

Consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence: Part 2, specific diseases

Pituitary adenomas are rare in children and young people under the age of 19 (hereafter referred to as CYP) but they pose some different diagnostic and management challenges in this age group than in adults. These rare neoplasms can disrupt maturational, visual, intellectual and developmental processes and, in CYP, they tend to have more occult presentation, aggressive behaviour and are more likely to have a genetic basis than in adults. Through standardized AGREE II methodology, literature review and Delphi consensus, a multidisciplinary expert group developed 74 pragmatic management recommendations aimed at optimizing care for CYP in the first-ever comprehensive consensus guideline to cover the care of CYP with pituitary adenoma. Part 2 of this consensus guideline details 57 recommendations for paediatric patients with prolactinomas, Cushing disease, growth hormone excess causing gigantism and acromegaly, clinically non-functioning adenomas, and the rare TSHomas. Compared with adult patients with pituitary adenomas, we highlight that, in the CYP group, there is a greater proportion of functioning tumours, including macroprolactinomas, greater likelihood of underlying genetic disease, more corticotrophinomas in boys aged under 10 years than in girls and difficulty of peri-pubertal diagnosis of growth hormone excess. Collaboration with pituitary specialists caring for adult patients, as part of commissioned and centralized multidisciplinary teams, is key for optimizing management, transition and lifelong care and facilitates the collection of health-related quality of survival outcomes of novel medical, surgical and radiotherapeutic treatments, which are currently largely missing.

Magneto-Immunoassay for the Detection and Quantification of Human Growth Hormone

Physiological and endocrine maintenance of a normal human growth hormone (hGH) concentration is crucial for growth, development, and a number of essential biological processes. In this study, we describe the preparation and characterization of magnetic nanoparticles coated with a gold shell (MNPs-Au). The optimal surface concentration of monoclonal anti-hGH antibodies (m-anti-hGH) on magnetic nanoparticles, as well as conditions that decrease non-specific interactions during the magneto-immunoassay, were elaborated. After the selective recognition, separation, and pre-concentration of hGH by MNPs-Au/m-anti-hGH and the hGH interaction with specific polyclonal biotin-labeled antibodies (p-anti-hHG-B) and streptavidin modified horseradish peroxidase (S-HRP), the MNPs-Au/m-anti-hGH/hGH/p-anti-hGH-B/S-HRP immunoconjugate was formed. The concentration of hGH was determined after the addition of 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide substrate solution for HRP; the absorbance at 450 nm was registered after the addition of STOP solution. The developed sandwich-type colorimetric magneto-immunoassay is characterized by a clinically relevant linear range (from 0.1 to 5.0 nmol L^-1, R² 0.9831), low limit of detection (0.082 nmol L^-1), and negligible non-specific binding of other antibodies or S-HRP. The obtained results demonstrate the applicability of the developed magneto-immunoassay for the concentration and determination of hGH in the serum. Additionally, important technical solutions for the development of the sandwich-type colorimetric magneto-immunoassay are discussed.

gp130/STAT3 signaling is required for homeostatic proliferation and anabolism in postnatal growth plate and articular chondrocytes

Growth of long bones and vertebrae is maintained postnatally by a long-lasting pool of progenitor cells. Little is known about the molecular mechanisms that regulate the output and maintenance of the cells that give rise to mature cartilage. Here we demonstrate that postnatal chondrocyte-specific deletion of a transcription factor Stat3 results in severely reduced proliferation coupled with increased hypertrophy, growth plate fusion, stunting and signs of progressive dysfunction of the articular cartilage. This effect is dimorphic, with females more strongly affected than males. Chondrocyte-specific deletion of the IL-6 family cytokine receptor gp130, which activates Stat3, phenocopied Stat3-deletion; deletion of Lifr, one of many co-receptors that signals through gp130, resulted in a milder phenotype. These data define a molecular circuit that regulates chondrogenic cell maintenance and output and reveals a pivotal positive function of IL-6 family cytokines in the skeletal system with direct implications for skeletal development and regeneration.

Successful treatment of pituitary gigantism

Pituitary gigantism is extremely rare, resulting from excessive secretion of growth hormone (GH) before fusion of epiphysial growth plates. We report a case of a 13-year-old boy, who presented with increased statural growth and headaches since the age of 10 years. On physical examination, his height was 180.7 cm (+3.3 SD) and Tanner stage V. Investigation revealed increased levels of serum age-adjusted and sex-adjusted insulin-like growth factor 1 (IGF-1) and failure of GH suppression during an oral glucose tolerance test (OGTT). MRI of the sellar region revealed a pituitary macroadenoma. He underwent transsphenoidal surgery and histopathological evaluation revealed mammosomatotropic adenoma. Three months after surgery, IGF-1 normalised, nadir GH during OGTT was less than 1 ng/mL and no residual tumour was found on the MRI. Genetic testing identified a mutation in the AIP gene. This case emphasises the importance of early diagnosis of gigantism, as treatment delay increases long-term morbidity.

Pituitary gigantism: a rare learning opportunity

INTRODUCTION

Pituitary gigantism is a rare but significant paediatric condition with complexities surrounding diagnosis and management. Transsphenoidal surgery (TSS) is the treatment of choice; however, medical treatment is often considered as adjuvant therapy.

CASE

A 10½ -year-old boy presented with tall stature and a height velocity of 11 cm/year. His height was 178.7 cm (+5.8 SD above mean) and insulin-like growth factor-1 (IGF-1) was elevated. An oral glucose tolerance test demonstrated non-suppression of growth hormone (GH). Initial contrast MRI was inconclusive, but C-11 methionine functional positron emission tomography CT identified a 6 mm pituitary microadenoma. A multidisciplinary team clinic held with the family allowed discussion about medical and surgical treatment options. Due to a number of factors including the patient's young age, prepubertal status, a wish to allow him to settle into his new high school and his desire to reach a final height taller than his father's height, it was decided to try medical therapy first with a somatostatin analogue. Pubertal induction was also commenced and bilateral epiphysiodesis surgery performed. Initial response to octreotide was positive; however, 4 months into therapy his IGF-1 was climbing and a repeat GH profile was not fully suppressed. The patient therefore proceeded to have successful TSS excision of the adenoma.

CONCLUSION

Rare cases such as this require sharing of knowledge and expertise, so the best possible care is offered. It is often necessary to work across sites and disciplines. Each case requires an individual approach tailored to the patient and their family.