Inoperable Giant Growth Hormone-secreting Pituitary Adenoma: Radiological Aspects, Clinical Management and Pregnancy Outcome

Giant growth hormone-secreting pituitary adenomas from the endocrinologist's perspective

OBJECTIVES

Since giant (≥40 mm) GH-secreting pituitary adenomas are rarely encountered, data on their characteristics and treatment outcomes are limited. We aimed to investigate the characteristics of giant GH-secreting pituitary adenomas and to compare their clinical, biochemical, imaging and histopathological features with non-giant macroadenomas.

MATERIALS AND METHODS

We have evaluated 15 (six female/nine male) and 57 (29 female/28 male) patients with acromegaly in giant and <40 mm adenoma groups, respectively. Patients with <40 mm adenoma were further divided into subgroups with adenoma size 20-29 mm and 30-39 mm.

RESULTS

In giant adenoma group, median (IQR) preoperative maximal diameter of adenoma was 40 mm (5 mm), median preoperative GH level was 40 (153.4) ng/mL and median baseline IGF-1 level was 2.19 (1.88) × ULN for age and sex. The number of surgeries was significantly higher in giant adenoma group (median 2, IQR 2) in which 66.7% of patients underwent repeated surgeries (p = 0.014). Residual tumor was detected after last operation in all patients with giant adenoma. Total number of treatment modalities administered postoperatively increased as adenoma size increased (p = 0.043). After a median follow-up duration of 10 years (IQR 10), hormonal remission was achieved in six patients (40%) of giant adenoma group, while the rate of hormonal remission in non-giant adenoma group was 37%. Although preoperative GH and IGF-1 levels and Ki-67 index tended to be higher with increasing adenoma size, there was no statistically significant difference between groups in terms of these variables, as well as age, sex and invasion status.

CONCLUSION

Hormonal remission rates of acromegaly patients with ≥20 mm pituitary macroadenoma were comparable. However, giant GH-secreting pituitary adenomas require an aggressive multimodal treatment approach.

Approach of Acromegaly during Pregnancy

Acromegaly-related sub/infertility, tidily related to suboptimal disease control (1/2 of cases), correlates with hyperprolactinemia (1/3 of patients), hypogonadotropic hypogonadism—mostly affecting the pituitary axis in hypopituitarism (10−80%), and negative effects of glucose profile (GP) anomalies (10−70%); thus, pregnancy is an exceptional event. Placental GH (Growth Hormone) increases from weeks 5−15 with a peak at week 37, stimulating liver IGF1 and inhibiting pituitary GH secreted by normal hypophysis, not by somatotropinoma. However, estrogens induce a GH resistance status, protecting the fetus form GH excess; thus a full-term, healthy pregnancy may be possible. This is a narrative review of acromegaly that approaches cardio-metabolic features (CMFs), somatotropinoma expansion (STE), management adjustment (MNA) and maternal-fetal outcomes (MFOs) during pregnancy. Based on our method (original, in extenso, English—published articles on PubMed, between January 2012 and September 2022), we identified 24 original papers—13 studies (3 to 141 acromegalic pregnancies per study), and 11 single cases reports (a total of 344 pregnancies and an additional prior unpublished report). With respect to maternal acromegaly, pregnancies are spontaneous or due to therapy for infertility (clomiphene, gonadotropins or GnRH) and, lately, assisted reproduction techniques (ARTs); there are no consistent data on pregnancies with paternal acromegaly. CMFs are the most important complications (7.7−50%), especially concerning worsening of HBP (including pre/eclampsia) and GP anomalies, including gestational diabetes mellitus (DM); the best predictor is the level of disease control at conception (IGF1), and, probably, family history of 2DM, and body mass index. STE occurs rarely (a rate of 0 to 9%); some of it symptoms are headache and visual field anomalies; it is treated with somatostatin analogues (SSAs) or alternatively dopamine agonists (DAs); lately, second trimester selective hypophysectomy has been used less, since pharmaco-therapy (PT) has proven safe. MNA: PT that, theoretically, needs to be stopped before conception—continued if there was STE or an inoperable tumor (no clear period of exposure, preferably, only first trimester). Most data are on octreotide > lanreotide, followed by DAs and pegvisomant, and there are none on pasireotide. Further follow-up is required: a prompt postpartum re-assessment of the mother’s disease; we only have a few data confirming the safety of SSAs during lactation and long-term normal growth and developmental of the newborn (a maximum of 15 years). MFO seem similar between PT + ve and PT − ve, regardless of PT duration; the additional risk is actually due to CMF. One study showed a 2-year median between hypophysectomy and pregnancy. Conclusion: Close surveillance of disease burden is required, particularly, concerning CMF; a personalized approach is useful; the level of statistical evidence is expected to expand due to recent progress in MNA and ART.

Fertility issues in aggressive pituitary tumors

The management of aggressive pituitary adenomas represents a special clinical challenge, and usually involves a combination of surgery, radiotherapy and pharmacological agents to control tumor growth and hormone abnormalities. Fertility is commonly affected in these patients due to compressive effects of the tumor, pituitary hormone dysfunction or as a result of the multiple therapies. The initial approach to restore fertility involves the reduction of tumor volume by the use of dopamine agonists in prolactinomas and by surgery in other pituitary adenomas. Somatostatin analogues are alternative options for GH, ACTH and TSH-secreting tumors. When present, pituitary deficiencies should be appropriately treated, particularly GH deficiency that has been associated with poor pregnancy rates in hypopituitary patients. Other therapies for aggressive pituitary tumors, such as invasive surgery, radiotherapy and temozolamide, may lead to infertility. In such cases, fertility preservation strategies might be considered and discussed with the patient desiring conception before or during treatment. In men and women with hypogonadotropic hypogonadism, administration of gonadotropins or pulse GnRH has resulted in satisfactory pregnancy rates. If spontaneous gestation is not achieved, assisted reproduction techniques can be employed as the last line of treatment. In any context, pre-conception counseling and care are essential as pregnancies in women with aggressive pituitary tumors should always be considered high risk.

Identification of Serum miRNA-423-5p Expression Signature in Somatotroph Adenomas

Circulating miRNAs are novel disease biomarkers that are valuable for diagnosis and prognosis. But the circulating miRNAs profile in somatotroph adenomas is still unknown. Therefore, serum exosomal miRNAs expression profiling in somatotroph adenomas was performed on 6 somatotroph adenomas and 6 normal controls. From the exosomal miRNAs expression profiling, we found 169 miRNAs differently expressed between somatotroph adenomas and healthy pituitary samples (p< 0.05, FC > 2). Among the 169 miRNAs, miR-423-5p was expressed lower in somatotroph adenomas than in healthy pituitary samples, which was proved by miRSCan Panel Chip™ qPCR. PTTG1 and SYT1 were the target mRNAs of miR-423-5p, and transcriptomics and proteomics profile both indicated the high expression of PTTG1 and SYT1 in somatotroph adenomas. H-scores were 223.1 ± 34.7 for PTTG1 and 163.4 ± 42.3 for SYT1 in 62 somatotroph adenomas specimens and 84.2 ± 21.3 for PTTG1 and 47.4 ± 17.2 for SYT1 in 6 healthy pituitary specimens by IHC. miR-423-5p inhibited the expression of SYT1 and PTTG1 at the mRNA and protein levels. Dual luciferase reporter gene assay shown was significantly reduced in the presence of miR-423-5p in GH3 cells transfected with wild-type PTTG1 3'UTR luciferase reporter plasmid but not reduced when transfected with the mutation PTTG1 3'UTR luciferase reporter plasmid (p<0.01). In vitro experiments showed that miR-423-5p induced cell apoptosis, inhibited cell proliferation, and reduced growth hormone release and migration of GH3 cells. The activity of miR-423-5p in GH3 cell was nearly blocked by its inhibitor. These results verified the central role of low miR-423-5p in promoting tumorigenesis in somatotroph adenomas. PTTG1 may act as biomarkers for clinical treatment of somatotroph adenomas.

Super Giant Growth Hormone-Secreting Pituitary Adenoma in Young Woman: From Ventricles to Nose

BACKGROUND

Giant pituitary adenomas are rare tumors that can have a devastating impact on a patient's life. They require a well-studied therapeutic approach that often combines different strategies.

CASE DESCRIPTION

A 29-year-old woman was diagnosed with the largest GH-secreting pituitary adenoma reported in the literature, to the best of the author's knowledge. The tumor was removed with a combined approach: endoscopic endonasal transsphenoidal and transcortical transventricular. All available acromegaly drugs were used. After 2 surgeries, a large part of the tumor was removed. Both postoperative courses were uneventful. Because the disease was still active, medical therapy was initiated. The combination of pasireotide, pegvisomant, and cabergoline permitted satisfactory control of hormonal levels.

CONCLUSIONS

Giant adenomas, >4 cm, are rare pituitary tumors. Therefore in order to achieve the best clinical results, they require complex management that involves a multidisciplinary team of ear, nose, and throat surgeons; endocrinologists; radiation therapists; ophthalmologists; and neurosurgeons.