Assessment of anterior pituitary reserve capacity based on growth hormone response to growth hormone-releasing peptide-2 test in the elderly

OBJECTIVE

The growth hormone (GH)-releasing peptide-2 (GHRP-2) test is relatively safe among endocrine stimulation tests for the elderly. We investigated whether anterior pituitary function in elderly patients could be assessed on the basis of GH response to the GHRP-2 test.

DESIGN

Sixty-five elderly patients aged 65 years and older with non-functioning pituitary neuroendocrine tumor (PitNET) who underwent pituitary surgery and preoperative endocrine stimulation tests were classified into the "GH normal group" and "GH deficiency group" based on GH response to the GHRP-2 test. The baseline characteristics and anterior pituitary function were compared between the groups.

RESULTS

Thirty-two patients were assigned to the GH normal group and 33 to the GH deficiency group. The cortisol and adrenocorticotropic hormone (ACTH) results in the corticotropin-releasing hormone test were significantly higher in the GH normal group than in the GH deficiency group (p < 0.001). The relationship between the cortisol and ACTH results and the GH response revealed significant correlations (p < 0.001). In addition, receiver operating characteristic curve analysis identified that the optimal cut-off point for a peak GH level in the correlation between adrenocortical function and GH response to the GHRP-2 test was 8.08 ng/mL (specificity 0.868, sensitivity 0.852).

CONCLUSION

The present study indicated that adrenocortical function was significantly correlated with GH response to the GHRP-2 test in elderly patients before pituitary surgery. For elderly patients with non-functioning PitNET, GH response to the GHRP-2 test may support in diagnosing adrenocortical insufficiency.

Study of 232 patients

PURPOSE

To investigate the status of preoperative anterior pituitary function in patients undergoing pituitary adenoma (PA) resection and to identify factors associated with preoperative anterior pituitary dysfunction (APD).

METHODS

Patients with functioning and nonfunctioning PAs who underwent pituitary adenoma resection for first time, from January 2009 to December 2019 were analyzed.

RESULTS

Total sample included 232 patients; 123 (53.2%) females, mean age at diagnosis was 53.3 years. Sixty-three percent presented as nonfunctioning PAs and 37.1% as functioning PAs. Eighty-eight percent were macroadenomas and 34.9% had cavernous sinus invasion. APD was demonstrated in 36.2% (n = 84) of the patients. The FSH/LH deficit was the most frequent anterior pituitary deficit (31.9%); followed by ACTH (18.1%); TSH (16.4%) and GH (13.8%). We identified as independent risk factors of APD, male sex (OR = 6.1, 95% CI = 3.3-11.0); age (OR = 1.03 for each year, 95% CI = 1.01-1.04), diabetes mellitus (OR = 3.5, 95% CI = 1.63-7.69), pituitary apoplexy presentation (OR = 4.3, 95% CI = 1.3-14.5) and tumor size (OR = 1.06 for each mm, 95% CI = 1.04-1.09). Nonfunctioning PAs (NFPA) had higher risk of APD than functioning PAs (FPA) (OR = 2.8 (95% CI = 1.5-5.0), but these differences disappeared after adjusted by tumor size (OR adjusted by tumor size = 1.7, 95% CI = 0.9-3.3). The tumor size with the highest diagnostic accuracy to predict hypopituitarism was 22 mm (sensitivity of 61.9% and specificity of 70.1%).

CONCLUSION

More than one third of PAs candidates for surgery had APD. The male sex, diabetes, an older age, pituitary apoplexy, and larger PAs were risk factors of APD. Hence, in these patients, the hormonal study should be prioritized and the need for dynamic tests must be carefully assessed.

Clinicopathological features and BRAFV600E mutations in patients with isolated hypothalamic-pituitary Langerhans cell histiocytosis

Background

Isolated hypothalamic-pituitary Langerhans cell histiocytosis (HPLCH) is very rare. We investigated the clinicopathological characteristics, endocrine function changes, BRAF^V600E mutations and treatments of isolated HPLCH.

Methods

We identified seven patients with isolated HPLCH by reviewing the clinical and pathological files in our hospital from 2007 to 2015. The clinical characteristics of the seven patients were retrospectively reviewed, especially the endocrine function changes. Immunostaining and mutation profiling of BRAF^V600E were performed.

Results

The seven HPLCH patients included three men and four women, aged 9–47 years. All patients presented with symptoms of central diabetes insipidus (CDI), and four displayed anterior pituitary hypofunction as well. Magnetic resonance imaging showed hypothalamic-pituitary axis involvement in all patients. There was no evidence for the involvement of other organs in all seven patients. Langerhans cell histiocytosis was confirmed by neuroendoscopic procedures, and immunohistochemical staining showed that all cases (7/7) were positive for CD68, CD1a, Langerin, and S-100. The BRAF^V600E mutation was detected in three of the six cases (3/6). Six patients had follow-up information; all received desmopressin acetate and high-dose corticosteroid therapy, and two patients received radiotherapy.

Conclusions

Our study indicated that all patients with isolated HPLCH had CDI as the earliest symptom, and more than half of the patients had anterior pituitary deficiencies. The BRAF^V600E mutation is a common genetic change in HPLCH patients. Treatment of HPLCH patients is difficult, and the progressive loss of endocrine function is irreversible in most cases.