Abstract: Objective To compare the clinical characteristics between pituitary gigantism patients with different age of onset. Methods This study retrospectively summarized the clinical data of patients diagnosed with pituitary gigantism in Peking Union Medical College Hospital from 1990 to 2018. Patients were divided into two groups according to the age of disease onset: patients with the age range of onset between 10～15 years old and the rest of patients. Results A total of 28 patients with pituitary gigantism were included in the study. Among them, 22 patients were male, with a median duration of 11.0 years (7.0, 13.8). 78.5% of the patients had a rapid growth in height at the first consultation, with an average height of (190.2±17.5)cm and an average height SDS(Ht SDS) of +4.5± 1.6 at the time of diagnosis. The pituitary MRI of 92.9% of patients demonstrated pituitary macroadenomas, of which 42.9% were pituitary giant adenomas. This study showed that the maximum diameter of the tumor in group with the age of onset between 10 to 15 years was significantly higher than that of control group (the age of onset between 10 to 15 years old: 2.9±1.3 cm vs. control group: (1.9±0.8)cm, P＜0.05), the proportion of pituitary giant adenoma was also significantly higher than control group (the age of onset between 10 to 15 years old: 62.5% vs control group: 16.7%, P＜0.05). Long-term follow-up data showed that the proportion of combined treatment (surgery & medication & radiotherapy) in group with onset of age between 10 to 15 years old was higher than that of control group (the age of onset between 10 to 15 years old: 31.2% vs control group: 8.3%). However, the cure rate between two groups in the long-term follow-up did not reach statistical significance. Conclusions This study shows that pituitary gigantism patients during puberty are prone to have larger adenoma and are more likely to develop into a giant pituitary adenoma. It is recommended to focus on this population in clinical practice and more aggressive treatment should be considered if necessary.

Key words: pituitary gigantism, growth hormone-secreting pituitary adenomas, pituitary giant adenoma