Cystic appearance on magnetic resonance imaging in bihormonal growth hormone and prolactin tumors in acromegaly

Surgical treatment of cystic pituitary adenomas: literature-based definitions and postoperative outcomes

BACKGROUND AND OBJECTIVES

To survey the applied definitions of 'cystic' among pituitary adenomas and evaluate whether postoperative outcomes differ relative to non-cystic counterparts.

METHODS

A literature search and meta-analysis was performed using PRISMA guidelines. Studies were eligible if novel data were reported regarding the applied definition of 'cystic' and postoperative outcomes among cases of surgically treated pituitary adenomas. Data were pooled with random effects meta-analysis models into cohorts based on the applied definition of 'cystic'. Categorical meta-regressions were used to investigate differences between cohorts. Among studies comparing cystic and non-cystic pituitary adenomas, meta-analysis models were applied to determine the Odds Ratio [95% Confidence Interval]. Statistical analyses were performed using Comprehensive Meta-Analysis (CMA, 4.0), with a priori significance defined as P < 0.05.

RESULTS

Ten studies were eligible yielding 283 patients with cystic pituitary adenomas. The definitions of 'cystic' mainly varied between the visual appearance of cystic components on preoperative magnetic resonance imaging and a volumetric definition requiring 50% or greater of tumor volume exhibiting cystic components. Tumor diameter was seldom reported with an associated standard deviation/error, limiting meta-analyses. When the data were pooled in accordance with the definition applied, there were no significant differences in the rates of gross total resection (P = 0.830), endocrinologic remission (P = 0.563), and tumor recurrence (P = 0.320). Meta-analyses on studies comparing cystic versus non-cystic pituitary adenomas indicated no significant difference in the rates of gross total resection (P = 0.729), endocrinologic remission (P = 0.857), and tumor recurrence (P = 0.465).

CONCLUSION

Despite some individual studies describing a significant influence of pituitary adenoma texture on postoperative outcomes, meta-analyses revealed no such differences between cystic and non-cystic pituitary adenomas. This discrepancy may be explained in part by the inconsistent definition of 'cystic' and between-group differences in tumor size. A notion of a field-standard definition of 'cystic' among pituitary adenomas should be established to facilitate inter-study comparisons.

Clinical Characteristics and Management of Cosecreting Thyroid Stimulating Hormone or Prolactin Pituitary Growth Hormone Adenomas: A Case-Control Study

OBJECTIVE

Cosecreting thyroid stimulating hormone (TSH) or prolactin (PRL) in patients with pituitary growth hormone (GH) adenomas has been rarely reported. Our study aimed to elucidate their clinical characteristics.

METHODS

We retrospectively collected data of 22 cases of cosecreting GH and TSH pituitary adenomas [(GH+TSH)oma] and 10 cases of cosecreting GH and PRL pituitary adenomas [(GH+PRL)oma] from Beijing Tiantan Hospital, Capital Medical University between January 2009 and January 2023. The clinical manifestation, preoperative hormone levels, imaging features, pathologic characteristics, and biochemical remission rates were compared among 335 patients with solo-secreting GH adenomas (GHoma) and 49 patients with solo-secreting TSH adenoma (TSHoma). Patients with (GH+TSH)oma and (GH+PRL)oma were grouped according to biochemical remission to explore the risk factors leading to biochemical nonremission.

RESULTS

Cosecreting pituitary GH adenomas had various clinical manifestations and a larger tumor volume and were more likely to invade the cavernous sinus bilaterally and compress the optic chiasm. GH and TSH levels were lower in (GH+TSH)oma than in GHoma or TSHoma. Solo part remission was observed both in (GH+TSH)oma and (GH+PRL)oma. Cavernous sinus invasion was an independent risk factor for biochemical nonremission in patients with (GH+TSH)oma and (GH+PRL)oma.

CONCLUSIONS

The clinical manifestation of (GH+TSH)oma and (GH+PRL)oma may be atypical. When screening for pituitary adenomas, a comprehensive evaluation of all pituitary target gland hormones is needed. Cosecreting pituitary GH adenomas are more aggressive and surgery is often unable to completely remove the tumor, requiring pharmacologic or radiological treatment if necessary. Clinicians should give high priority to biochemical remission, although solo part remission may occur.

Differences between GH and PRL co-secreting and GH-secreting pituitary adenomas. A series of 604 cases

PURPOSE

To evaluate differences in clinical presentation and in surgical outcomes between growth hormone-secreting pituitary adenomas (GH-PAs) and GH and prolactin co-secreting pituitary adenomas (GH&PRL-PAs).

METHODS

Multicenter retrospective study of 604 patients with acromegaly submitted to pituitary surgery. Patients were classified into two groups according to serum PRL levels at diagnosis and immunohistochemistry (IHC) for PRL: a) GH&PRL-PAs when PRL levels were above the upper limit of normal and IHC for GH and PRL was positive or PRL levels were >100ng/and PRL IHC was not available (n=130) and b) GH-PAs who did not meet the previously mentioned criteria (n=474).

RESULTS

GH&PRL-PAs represented 21.5% (n=130) of patients with acromegaly. The mean age at diagnosis was lower in GH&PRL-PAs than in GH-PAs (P<0.001). GH&PRL-PAs were more frequently macroadenomas (90.6% vs. 77.4%, P=0.001) and tended to be more invasive (33.6% vs. 24.7%, P=0.057) than GH-PAs. Furthermore, they had presurgical hypopituitarism more frequently (OR 2.8, 95% CI 1.83-4.38). IGF-1 upper limit of normality (ULN) levels at diagnosis were lower in patients with GH&PRL-PAs (median 2.4 [IQR 1.73-3.29] vs. 2.7 [IQR 1.91-3.67], P=0.023). There were no differences in the immediate (41.1% vs 43.3%, P=0.659) or long-term post-surgical acromegaly biochemical cure rate (53.5% vs. 53.1%, P=0.936) between groups. However, there was a higher incidence of permanent arginine-vasopressin deficiency (AVP-D) (7.3% vs. 2.4%, P=0.011) in GH&PRL-PAs patients.

CONCLUSIONS

GH&PRL-PAs are responsible for 20% of acromegaly cases. These tumors are more invasive, larger and cause hypopituitarism more frequently than GH-PAs and are diagnosed at an earlier age. The biochemical cure rate is similar between both groups, but patients with GH&PRL-PAs tend to develop permanent postsurgical AVP-D more frequently.

Surveillance Imaging Strategies for Pituitary Adenomas: When, How Frequent, and When to Stop

OBJECTIVE

To describe a practical approach of when and how often to perform imaging, and when to stop imaging pituitary adenomas (PAs).

METHODS

A literature review was carried out and recommendations provided are derived largely from personal experience.

RESULTS

Magnetic resonance imaging is the mainstay imaging modality of choice in the assessment, treatment planning, and follow-up of PAs. These adenomas are discovered incidentally during imaging for a variety of unrelated conditions, because of clinical symptoms related to mass effects on the adjacent structures, or during workup for functional alterations of the adenoma. Imaging is also used in the preoperative and postoperative phases of assessment of PAs, for surgical and radiotherapy planning, for postoperative surveillance to assess for adenoma stability and detection of adenoma recurrence, and for surveillance to monitor for adenoma growth in unoperated PAs. Currently, because there are no evidence-based consensus recommendations, the optimal strategy for surveillance imaging of PAs is not clearly established. Younger age, initial adenoma size, extrasellar extension, mass effect, cavernous sinus invasion, functional status, histopathologic characteristics, cost considerations, imaging accessibility, patient preference, and patient contraindications (eg, implanted metallic devices and patient claustrophobia) are all important factors that influence the strategy for surveillance imaging.

CONCLUSIONS

This review provides a practical approach of performing surveillance imaging strategies for PAs that should be individualized based on clinical presentation, history, adenoma morphology on imaging, and histopathologic characteristics.

Consensus on criteria for acromegaly diagnosis and remission

PURPOSE

The 14th Acromegaly Consensus Conference was convened to consider biochemical criteria for acromegaly diagnosis and evaluation of therapeutic efficacy.

METHODS

Fifty-six acromegaly experts from 16 countries reviewed and discussed current evidence focused on biochemical assays; criteria for diagnosis and the role of imaging, pathology, and clinical assessments; consequences of diagnostic delay; criteria for remission and recommendations for follow up; and the value of assessment and monitoring in defining disease progression, selecting appropriate treatments, and maximizing patient outcomes.

RESULTS

In a patient with typical acromegaly features, insulin-like growth factor (IGF)-I > 1.3 times the upper limit of normal for age confirms the diagnosis. Random growth hormone (GH) measured after overnight fasting may be useful for informing prognosis, but is not required for diagnosis. For patients with equivocal results, IGF-I measurements using the same validated assay can be repeated, and oral glucose tolerance testing might also be useful. Although biochemical remission is the primary assessment of treatment outcome, biochemical findings should be interpreted within the clinical context of acromegaly. Follow up assessments should consider biochemical evaluation of treatment effectiveness, imaging studies evaluating residual/recurrent adenoma mass, and clinical signs and symptoms of acromegaly, its complications, and comorbidities. Referral to a multidisciplinary pituitary center should be considered for patients with equivocal biochemical, pathology, or imaging findings at diagnosis, and for patients insufficiently responsive to standard treatment approaches.

CONCLUSION

Consensus recommendations highlight new understandings of disordered GH and IGF-I in patients with acromegaly and the importance of expert management for this rare disease.

Prolactin and Growth Hormone Signaling and Interlink Focused on the Mammosomatotroph Paradigm: A Comprehensive Review of the Literature

Prolactin (PRL) and growth hormone (GH) are peptide hormones that bind to the class 1 cytokine receptor superfamily, a highly conserved cell surface class of receptors. Both hormones control their own secretion via a negative autocrine loop in their own mammosomatotroph, lactotroph or somatotroph. In this regard, GH and PRL are regulated by similar signaling pathways involving cell growth and hormone secretion. Thus, GH and PRL dysregulation and pituitary neuroendocrine tumor (PitNET) development may have common pathogenic pathways. Based on cell linage, lactotroph and somatotroph PitNETs come from pituitary-specific POU-class homeodomain transcription factor (Pit-1). Mammosomatotroph and plurihormonal PitNETs are a unique subtype of PitNETs that arise from a single-cell population of Pit-1 lineage. In contrast, mixed somatotroph-lactotroph PitNETs are composed of two distinct cell populations: somatotrophs and lactotrophs. Morphologic features that distinguish indolent PitNETs from locally aggressive ones are still unidentified, and no single prognostic parameter can predict tumor aggressiveness or treatment response. In this review, we aim to explore the latest research on lactotroph and somatotroph PitNETs, the molecular mechanisms involved in PRL and GH axis regulation and the signaling pathways involved in their aggressiveness, particularly focused on mammosomatotroph and mixed subtypes. Finally, we summarize epidemiological, clinical, and radiological features of these exceptional tumors. We aim to shed light, from basic to clinical settings, on new perspectives and scientific gaps in this field.

Acromegaly: pathogenesis, diagnosis, and management

Growth hormone-secreting pituitary adenomas that cause acromegaly arise as monoclonal expansions of differentiated somatotroph cells and are usually sporadic. They are almost invariably benign, yet they can be locally invasive and show progressive growth despite treatment. Persistent excess of both growth hormone and its target hormone insulin-like growth factor 1 (IGF-1) results in a wide array of cardiovascular, respiratory, metabolic, musculoskeletal, neurological, and neoplastic comorbidities that might not be reversible with disease control. Normalisation of IGF-1 and growth hormone are the primary therapeutic aims; additional treatment goals include tumour shrinkage, relieving symptoms, managing complications, reducing excess morbidity, and improving quality of life. A multimodal approach with surgery, medical therapy, and (more rarely) radiation therapy is required to achieve these goals. In this Review, we examine the epidemiology, pathogenesis, diagnosis, complications, and treatment of acromegaly, with an emphasis on the importance of tailoring management strategies to each patient to optimise outcomes.

Clinical features and complications of acromegaly at diagnosis are not all the same: data from two large referral centers

PURPOSE

The number of international acromegaly related registries is increasing; however, heterogeneity of acromegaly symptoms and signs across countries is not well described. We compared clinical disease manifestations at diagnosis between two large University referral centers from two continents.

METHODS

Retrospective, comparative epidemiological study of acromegaly patients at two centers: (i) C. I. Parhon National Institute of Endocrinology, 'Carol Davila' University of Medicine and Pharmacy Bucharest, Romania (Parhon), and (ii) Pituitary Center, Oregon Health & Science University, Portland, Oregon, United States (OHSU) from approved data repositories was undertaken. Data were extracted from medical charts and questionnaires. Binary logistic regression analysis was undertaken for the most frequently noted symptoms and clinical signs.

RESULTS

The study included 216 patients (87 Parhon, 129 OHSU). Age, sex, and median delay in diagnosis were similar between centers. IGF-1 index was higher in patients at Parhon (3.3 vs 2.1, P < 0.001). The top five symptoms at both centers were enlarged hands/feet, headache, arthralgia, fatigue, and irregular menses in women. A significant difference was noted for multiple signs and symptoms frequency, often > 20 percentage points between centers. Center was a predictor of many signs and symptoms, independent of acromegaly biochemical severity or disease duration.

CONCLUSION

We show in the first comparative study that differences in medical practice, documentation, and likely cultural differences can influence patients' symptom(s) reporting and screening patterns in geographically different populations. Pooling data into large multicenter international registry databases may lead to loss of regional characteristics and thus a mixed overall picture of combined cohorts.