Postoperative growth hormone dynamics in clinically nonfunctioning pituitary adenoma

Exploring endocrinological pitfalls in pituitary surgery in the elderly

Background

Endoscopic transsphenoidal surgery (ETSS) is performed more frequently in elderly patients. We investigated endocrinological pitfalls in pituitary surgery in the elderly by a comparative study focusing only on elderly patients.

Methods

Ninety-nine elderly patients aged 65 years and over with non-functioning pituitary adenoma (NFPA) who underwent ETSS were retrospectively examined and classified into the early (aged 65-74 years) and late (aged 75 years and over) elderly groups. The baseline characteristics and anterior pituitary function were compared between the groups.

Results

Seventy patients were assigned to the early elderly group and 29 to the late elderly group. Thyroid-stimulating hormone (TSH) response in preoperative and postoperative thyrotropin-releasing hormone (TRH) tests revealed a significant difference between the groups. Preoperative and postoperative TSH responses were significantly correlated in both groups. Residual analysis of the correlation between preoperative free triiodothyronine (T3) secretion quantity and preoperative TSH response in both groups, which was significant, indicated that preoperative TSH response was significantly normal when preoperative free T3 secretion quantity was normal in the early elderly group, but preoperative free T3 secretion quantity was significantly lower regardless of preoperative TSH response in the late elderly group.

Conculsions

The present study suggested that preoperative and postoperative TSH secretory capacity was presumed to be normal when preoperative free T3 levels were normal in the early elderly patients with NFPA. On the other hand, TSH secretory capacity in the late elderly patients could only be assessed by the TRH test, which should be taken into account.

Predictive factors for recovery from adult growth hormone deficiency after transsphenoidal surgery for nonfunctioning pituitary adenoma

OBJECTIVE

Recovery from adult growth hormone deficiency (AGHD) after transsphenoidal surgery (TSS) has not been well discussed because of the lack of examinations including pituitary provocation tests (PPTs) before and after the procedure. This study aimed to evaluate the growth hormone (GH) axis function of patients with nonfunctioning pituitary adenoma (NFPA) via pre- and postoperative PPTs. Moreover, the predictive factors for recovery from AGHD after TSS were validated to facilitate surgery for AGHD in patients with NFPA.

METHODS

In total, 276 patients (median age 60.0 years) who underwent TSS for NFPA were included in this study. PPTs were performed before and 3 months after TSS. Then, the relationships between recovery from AGHD after TSS and clinical, surgical, and hormonal factors, including peak GH level based on PPTs, were evaluated statistically.

RESULTS

In this study, 114 patients were diagnosed with preoperative AGHD. Approximately 25.4% recovered from AGHD after TSS. In contrast, among the 162 patients without preoperative AGHD, 13 (8.0%) had newly developed postoperative AGHD. The predictive factors for recovery from AGHD were younger age, female sex, initial TSS, and high peak GH level based on preoperative PPT. According to the receiver operating characteristic curve analysis, patients who were aged ≤ 62.2 years and had a peak GH level of ≥ 0.74 μg/L based on preoperative PPT were likely to recover from AGHD (sensitivity: 82.8%, specificity: 72.9%, and area under the curve: 0.8229).

CONCLUSIONS

AGHD caused by NFPA can improve after initial TSS among young patients with certain peak GH levels assessed by preoperative PPT. Whether TSS for NFPA can promote recovery from AGHD is worth considering in some patients.

Association between overweight and growth hormone secretion in patients with non-functioning pituitary tumors

Introduction

Growth hormone (GH) deficiency (GHD) is often complicated by non-functioning pituitary tumors (NFPTs); however, its prevalence remains unclear because preoperative screening for GHD with provocative tests is not recommended. Accordingly, we attempted to clarify the characteristics of GHD in unoperated patients with NFPT.

Materials and methods

We retrospectively reviewed adult patients with non-functioning pituitary adenoma (NFPA) and Rathke’s cyst who underwent preoperative GH-releasing peptide-2 (GHRP-2) tests from January 2013 to December 2016. We investigated the association between peak GH response to GHRP-2 and background characteristics.

Results

Among 104 patients (85 NFPA and 19 Rathke’s cysts), 45 (43%) presented severe GHD, as diagnosed using GHRP-2 tests. Body mass index (β = -0.210, P = 0.007), free thyroxine (β = 0.440, P < 0.001), and tumor height (β = -0.254, P < 0.001) were significant variables for determining the peak GH response to GHRP-2 in multiple regression analyses. Overweight (odds ratio, 3.86; 95% confidence interval, 1.02–14.66) was significantly associated with severe GHD after adjustment for age, sex, creatinine, free thyroxine, tumor height and clinical diagnosis. The regression slopes between tumor height and peak GH response to GHRP-2 significantly differed between overweight patients and non-overweight individuals, as determined by analysis of covariance (P = 0.040). In the 48 patients who underwent postoperative GHRP-2 tests, severe postoperative GHD was significantly more common in overweight patients than non-overweight individuals (100% vs. 48%, P < 0.001).

Conclusion

We observed a negative synergistic effect between overweight and tumor size on GH secretion in patients with NFPTs, indicating that GH provocation tests for diagnosing underestimated GHD could be considered in overweight unoperated patients with large NFPTs.

Silent Corticotroph Tumor with Adrenocortical Choristoma in an Eleven-year-old Boy

Silent corticotroph tumors are composed of corticotroph cells, but do not manifest any biochemical or clinical evidence of hypercortisolism. A choristoma is a benign, congenital proliferation of histologically mature tissue elements normally not present at the site of occurrence. The existence of adrenocortical cells within the pituitary gland, which can be explained as a choristoma, is a very rare entity, and the co-occurrence of these two entities have only been reported in few cases. We report an 11-year-old boy with central hypothyroidism. On cranial magnetic resonance imaging a pituitary tumor was detected, and histopathological studies led to a diagnosis of an adrenal choristoma and a silent corticotroph tumor in the pituitary gland. The presence of adrenocortical cells were confirmed by positive calretinin, inhibin and Melan A staining, and the corticotroph cells by immunohistochemistry demonstrating adrenocorticotropic hormone positivity. Herein, we report the fourth and the youngest case of silent corticotroph tumor with adrenocortical choristoma in the literature. Even though the underlying mechanism is not fully understood, suggested mechanisms are discussed.

Preoperative growth hormone (GH) peak values during a GH releasing peptide-2 test reflect the severity of hypopituitarism and the postoperative recovery of GH secretion in patients with non-functioning pituitary adenomas

Non-functioning pituitary adenoma (NFPA) is one common cause of adult growth hormone deficiency (AGHD). In Japan, a GH-releasing peptide (GHRP)-2 test is used to evaluate GH secretion. Although the cut-off for peak GH during a GHRP-2 test for severe AGHD is ≤9 ng/mL, severe AGHD may further diminish responses (range, nearly no-response to ≤9 ng/mL). We studied whether the peak GH responses during a GHRP-2 test could be predicted based on clinical characteristics of patients with NFPA. We compared patients with almost no-response during a GHRP-2 test with other patients considered as severe AGHD. Among the 76 patients with NFPA who were admitted to our institution, 36 patients (mean age, 61 years; male/female, n = 23/n = 13) were diagnosed with severe AGHD based on a preoperative GHRP-2 test. Based on the preoperative median peak GH concentration (2.83 ng/mL), patients were divided into two groups (<median = low or group L, n = 18; ≥median = moderate or group M, n = 18). Clinical manifestations, body mass index, severity of hypopituitarism and tumor size, volume, and extension were analyzed retrospectively. Compared with group M, group L patients were significantly older and more gonadotropin and ACTH deficient. A lower peak GH release during a GHRP-2 test was associated with a higher number of anterior pituitary hormone deficiencies across all 76 patients. Postoperatively, seven in group M and no patient in group L were assessed as having no longer severe AGHD, respectively. Preoperative peak GH concentrations assessed during a GHRP-2 test reflected the severity of hypopituitarism and the recovery of postoperative GH secretion.

Non-functioning pituitary adenomas: indications for pituitary surgery and post-surgical management

PURPOSE

Non-functioning pituitary adenomas (NFPAs) are associated with impaired well-being, increased comorbidities, and reduced long-term survival. Data on optimal management of NFPAs around surgical treatment are scarce, and postoperative treatment and follow-up strategies have not been evaluated in prospective trials. Here, we review the preoperative, perioperative, and early postoperative management of patients with NFPAs.

METHODS

We searched Medline and the Cochrane Library for articles published in English with the following items "Pituitary neoplasms AND Surgery" and "Surgery AND Hypopituitarism". Studies containing detailed analyses of the management of NFPAs in adult patients, including pituitary surgery, endocrine care, imaging, ophthalmologic assessment and long-term outcome were reviewed.

RESULTS

Treatment options for NFPAs include active surveillance, surgical resection, and radiotherapy. Pituitary surgery is currently recommended as first-line treatment in patients with visual impairment due to adenomas compressing the optic nerves or chiasma. Radiotherapy is reserved for large tumor remnants or tumor recurrence following one or more surgical attempts. There is no consensus of optimal pre-, peri-, and postoperative management such as timing, frequency, and duration of endocrine, radiologic, and ophthalmologic assessments as well as management of smaller tumor remnants or tumor recurrence.

CONCLUSIONS

In clinical practice, there is a great variation in the treatment and follow-up of patients with NFPAs. We have, based on available data, suggested an optimal management strategy for patients with NFPAs in relation to pituitary surgery. Prospective trials oriented at drawing up strategies for the management of NFPAs are needed.