Epidemiology and radiological geometric assessment of pituitary macroadenomas: population-based study

Surgical outcomes in patients with acromegaly: Microscopic vs. endoscopic transsphenoidal surgery

Transsphenoidal resection of growth hormone-secreting pituitary neuroendocrine tumors remains the first-line treatment for acromegaly. This can be performed through microsurgery or endoscopic surgery. For the past decades, endoscopic surgery has become the preferred technique in an increasing number of centers worldwide. However, whether it offers superior clinical outcomes has yet to be determined. In this paper, we performed a narrative review of the literature comparing both techniques in the treatment of acromegaly. We critically assessed available comparative studies from an objective perspective to determine their suitability for defining superiority of either technique. Available evidence displays substantial methodological variations and reports conflicting findings. Although endoscopic surgery provides a wider exposure and enhanced visibility of the surgical field, this does not consistently translate into better clinical outcomes, as most tumors are equally accessible through both techniques. Postoperative outcomes such as remission and complication rates are similar between both techniques. The management of acromegaly should be performed by experienced pituitary neurosurgeons, regardless of the approach. The involvement of a multidisciplinary team in a dedicated pituitary center is critical to ensure optimal outcomes.

Metabolic Disorders During Prolactinomas

The metabolic profile during prolactinoma may be subject to significant changes. We aimed to describe the different metabolic aspects in patients monitored for prolactinoma and to study the correlations between the size of the prolactinoma and the metabolic parameters. We conducted a retrospective, descriptive, and analytical study of 77 cases of prolactinomas collected and monitored at the endocrinology and diabetology department of the Hedi Chaker Hospital in Sfax between 2000 and 2017. Our patients were divided into three groups according to the size of their prolactinomas. Statistical correlations were sought between tumor size and clinical and biological parameters. The mean age of our patients was 38.3 ± 14.2 years. They were divided into 51 women (66.2%) and 26 men (33.7%). Pituitary tumor syndrome was the most common circumstance of discovery in our population (62.3%). The clinical examination revealed an average waist circumference of 95.71 cm. Android fat distribution was observed in 25 women (49%) and 12 men (46.1%). A statistically significant positive correlation was objectified between waist circumference and tumor size (r = 0.29 and P = 0.019). The average body mass index was 28.08 kg/m2. Obesity was noted in 56 cases (72.7%). Glucose tolerance disorders and hypertriglyceridemia were also more evident each time prolactinoma size increased in contrast to the level of high-density lipoprotein cholesterol which decreased with adenoma size. Our study highlighted the metabolic and hormonal repercussions of prolactinomas. Metabolic syndrome was more common in patients with larger prolactinoma. These results should guide the initial assessment and therapeutic management of prolactin adenomas.

Prolactin-secreting pituitary adenomas: male-specific differences in pathogenesis, clinical presentation and treatment

Prolactinomas (PRLomas) constitute approximately half of all pituitary adenomas and approximately one-fifth of them are diagnosed in males. The clinical presentation of PRLomas results from direct prolactin (PRL) action, duration and severity of hyperprolactinemia, and tumor mass effect. Male PRLomas, compared to females, tend to be larger and more invasive, are associated with higher PRL concentration at diagnosis, present higher proliferative potential, are more frequently resistant to standard pharmacotherapy, and thus may require multimodal approach, including surgical resection, radiotherapy, and alternative medical agents. Therefore, the management of PRLomas in men is challenging in many cases. Additionally, hyperprolactinemia is associated with a significant negative impact on men's health, including sexual function and fertility potential, bone health, cardiovascular and metabolic complications, leading to decreased quality of life. In this review, we highlight the differences in pathogenesis, clinical presentation and treatment of PRLomas concerning the male sex.

Clinical Significance of T2-Weighted Sequence Intensity on Magnetic Resonance Imaging in Clinically Non-Functioning Pituitary Adenomas

BACKGROUND

Little is known about the relationship between signal intensity patterns on T2-weighted magnetic resonance imaging (MRI) in non-functioning pituitary adenomas (NFPAs).

OBJECTIVE

In this study, the clinical, hormonal, histological features, and therapeutic responses were evaluated according to the T2 signal intensity in NFPAs.

METHODS

This retrospective and multicenter study included a group of 166 NFPA patients (93 men, 56%, mean age 58.5 ±14.8 yr).

RESULTS

Approximately half of the tumors (n=84, 50.6%) were hyperintense, while 34.3% (n=57) and 15.1% (n=25) were iso- and hypointense, respectively. The median maximum tumor diameter of the isointense group [16 (13-25) mm] was significantly lower than that of the hyperintense [23 (16.6-29.7) mm] group (p=0.003). Similarly, the tumor volume of the isointense group [1,523 (618-5,226) mm3] was significantly lower than that of the hyperintense [4,012 (2,506-8,320) mm3] group (p=0.002). Chiasmatic compression occurred less frequently in tumors with isointense signal characteristics (38.6%) compared to tumors with hypointense (68%) and hyperintense (65.5%) signal characteristics (p=0.003). Invasive adenomas (p=0.001) and the degree of cavernous sinus invasion (p<0.001) were more frequent in the hyperintense adenoma group compared to the remaining groups. Plurihormonal tumors and silent lactotroph adenomas were more frequent in the isointense tumor group.

CONCLUSION

In conclusion, hyperintensity on T2-weighted MRI in NFPAs is associated with larger and more invasive tumors compared to isointense NFPAs.

Current and Future Perspectives of Microscopic and Endoscopic Transsphenoidal Surgery for Pituitary Adenomas: A Narrative Review

Transsphenoidal resection remains the standard treatment for most pituitary adenomas. However, the ideal surgical approach to safely access these lesions, either microsurgical or endoscopic, continues to be debated. Since the introduction of endoscopic transsphenoidal surgery, centers around the world have increasingly adopted this technique, experiencing a shift away from the conventional microsurgical approach. Large series reporting the efficacy and safety of endoscopic surgery have fueled a growing interest in comparing clinical outcomes between both approaches. Still, proving superiority of either surgical approach remains an elusive task due to the inherent drawbacks of surgical observational studies, as we are still faced with a growing body of evidence reporting conflicting results. Thus, a comprehensive discussion regarding the reach and limitations of both techniques becomes necessary. In this narrative review, we perform a critical appraisal of the literature and provide an expert opinion on the state-of-the-art in transsphenoidal surgery for pituitary adenomas. The advantages and limitations of each approach are assessed and compared from a technical standpoint, and their reported outcomes evaluated in the framework of this transition phase. Available evidence should be interpreted in light of individual patient characteristics and within the context of each medical center, taking into consideration the known impact that surgical expertise and multidisciplinary management hold on clinical outcomes.

MRI and Trouillas' grading system of pituitary tumors: the usefulness of T2 signal intensity volumetric values

PURPOSE

To classify pituitary macroadenomas according to the Trouillas' grading system; to compare this grading system with T2 values of volumetric signal intensity to determine T2 values able to predict the final grade.

METHODS

A total of 106 patients with macroadenomas were grouped according to the grading system score combining proliferation and invasiveness criteria of Trouillas' classification. Normalized volumetric signal intensity values were extracted from coronal T2-weighted images (nT2mean, nT2Max, nT2min) and were compared with the final grading score system.

RESULTS

Thirty-three patients were in grade 1a (non-invasive, non-proliferative tumors), 17 patients in grade 1b (non-invasive, proliferative tumors), 36 patients in grade 2a (invasive, non-proliferative tumors), and 20 patients in grade 2b (invasive, proliferative tumors). No patient was in grade 3 (metastatic tumors). nT2Max and nT2min were the best quantitative values to discriminate invasive from non-invasive grades; in invasive grades, nT2Max intensity values were higher, and nT2min intensity values were lower than in non-invasive grades. Receiver operating characteristic analysis of nT2 values showed that nT2min values had a better diagnostic performance than nT2Max values because they allowed differentiating with a moderate accuracy invasive tumors (2a or 2b grades) from both non-invasive proliferative tumors (1b) and non-invasive-non proliferative tumors (1a) (2a vs 1b: AUCnT2min = 0.78, 2b vs 1b: AUCnT2min = 0.72, 2a vs 1a: AUCnT2min = 0.72, 2b vs 1a AUCnT2min = 0.69).

CONCLUSION

Volumetric nT2Max and nT2min values of MRI might be practical and non-invasive markers for assessing tumor invasiveness although nT2 min signal intensity values have more effects in discriminating tumor's invasive behavior.

The environmental burden on endocrine neoplasia: a review on the documented impact of endocrine disrupting chemicals

INTRODUCTION

Endocrine-disrupting chemicals (EDCs) have gained more importance in the past decade, mostly due to their role in the pathogenesis of disease, especially in carcinogenesis. However, there is limited literature on the environmental burden on some of the less common endocrine neoplasia.

AREAS COVERED

This review focuses on both observational and experimental studies linking exposure to EDCs and endocrine neoplasia specifically pituitary, thyroid, adrenal and neuroendocrine tumors. Following PRISMA guidelines, a search of English peer-reviewed literature was performed using Medline and Google Scholar, giving preference to recent publications.

EXPERT OPINION

Exposure to EDC occurs not only in the household but also at work, whether it is in the office, factory, or farm and during transport from one location to another. Many studies have evaluated the effect of single environmental agents; however, humans are rarely exposed to only one EDC. Different EDCs and different levels of exposure may interact together to provide either a synergistic and/or an antagonistic disruption on human health, and hence a complex mechanism to elucidate. The ultimate adverse effect is difficult to predict, as it is not only influenced by the degree of exposure, but also by genetics, lifestyle, comorbidities, and other stressors.

The prevalence of acromegaly is higher than previously reported: Changes over a three-decade period

OBJECTIVE

To study time-related changes in the prevalence and patient characteristics of acromegaly, as well as to assess the impact of changes in treatment on disease control.

METHODS

A total of 107 patients with acromegaly were identified by healthcare registries and subsequently validated by patient chart review over a three-decade period (1992-2021). A systematic literature review focusing on the incidence and prevalence of acromegaly was performed identifying 31 studies.

RESULTS

The prevalence of acromegaly significantly increased throughout the study period (R²  = 0.94, p < .001) and was 122 cases/10⁶ persons in 2021 whereas the annual incidence remained constant at 4.6 cases/10⁶ persons. The age at the first sign of acromegaly and the age at diagnosis significantly increased during the study period, whereas growth hormone and insulin-like growth factor I decreased. Incidentalomas constituted 32% of all cases diagnosed with acromegaly in the last decade. Primary surgery was used in 93% of all cases, and repeated surgery decreased from 24% to 10% during the three decades. The use of first-generation somatostatin analogues (21%-48%) and second-line medical treatment (4%-20%) increased with a concomitant improvement of biochemical disease control (58%-91%).

CONCLUSION

The prevalence of acromegaly is higher than previously reported and the clinical presentation has shifted towards a milder phenotype. Modern treatment of acromegaly enables individualized treatment and disease control in the majority of patients.

A current perspective of pituitary adenoma MRI characteristics: a review

INTRODUCTION

MR imaging is an essential and fundamental tool in the diagnosis, management, and follow-up of patients with pituitary adenomas (PAs). Recent advances have continued to enhance the usefulness of this imaging modality.

AREAS COVERED

This article focuses on signal intensity patterns of PAs and associated clinical characteristics, vertical extension patterns, and cavernous sinus invasion with a special focus on the clinical implications that arise. A search using Medline and Google Scholar was conducted using different combinations of relevant keywords, giving preference to recent publications.

EXPERT OPINION

A higher proportion of GH-secreting PAs are hypointense on T2 weighted images compared to other tumor subtypes. Hypointense tumors are generally smaller compared to hyperintense ones, and among the GH-secreting subgroup, a better response to somatostatin analogue treatment was noted together with an association for a densely granulated pattern. Nonfunctional PAs show a predilection to extend upwards while GH-secreting PAs and prolactinomas show a predominantly inferior extension growth pattern. Further studies to better understand the mechanisms responsible for this behavior are anticipated. Further development, refining and validation of predictive scoring systems for tumor behavior might be useful adjuncts in the management of patients with PAs.

Epidemiology and blood parameter changes in Cushing's syndrome - a population-based study

PURPOSE

To provide complete epidemiological data on Cushing's syndrome (CS) with analysis and differentiation of biochemical parameters, including blood count indices and serum inflammation-based scores.

METHODS

Clinical records of 35 patients diagnosed with CS between 2008 and 2020 at Malta's only central National Health Service hospital were retrospectively analyzed. Detailed clinical and biochemical data were obtained for each patient. Correlation and receiver operator characteristics (ROC) curve analyses were used to establish a threshold value for different variables to predict malignant CS.

RESULTS

Standardized incidence rate (SIR) (/million/year) of CS was 4.5, and SIR of Cushing's disease (CD) was 2.3, 0.5 for ectopic CS, 1.5 for cortisol secreting adrenal adenoma, and 0.3 cases for cortisol-producing ACC. Malignant cause of CS had statistically significantly higher cortisol levels and size of tumor and lower potassium at diagnosis (P < 0.001). Additionally, malignant causes had a higher neutrophil-to-lymphocyte ratio (NLR) (P = 0.001) and systemic immune inflammation index (P = 0.005) and a lower lymphocyte-to-monocyte ratio (P < 0.001). Using ROC curve analysis to predict malignant cause of CS, a potassium level of < 3.05 was 75% sensitive and 100% specific (ROC-AUC 0.907, P = 0.001), a post-ODST cortisol level of > 841 nmol/L was 100% sensitive and 91% specific (ROC-AUC 0.981, P < 0.001), while a NLR ratio > 3.9 was 100% sensitive and 57.7% specific (ROC-AUC 0.885, P = 0.001).

CONCLUSION

Biochemical and blood count indices and serum inflammatory-based scores differ remarkably between benign and malignant causes of endogenous CS. Such indices can help predict the severity of disease and prognosis.

Growth hormone secreting pituitary adenomas show distinct extrasellar extension patterns compared to nonfunctional pituitary adenomas

PURPOSE

Patterns of extension of pituitary adenomas (PA) may vary according to PA subtype. Understanding extrasellar extension patterns in growth hormone PAs (GHPA) vis-a-vis nonfunctional PAs (NFPAs) may provide insights into the biology of GHPA and future treatment avenues.

METHODS

Preoperative MR imaging (MRI) in 179 consecutive patients treated surgically for NFPA (n = 139) and GHPA (n = 40) were analyzed to determine patterns of extrasellar growth. Extension was divided into two principal directions: cranio-caudal (measured by infrasellar/suprasellar extension), and lateral cavernous sinus invasion (CSI) determined by Knosp grading score of 3-4. Suprasellar extension was defined as tumor extension superior to the tuberculum sellae- dorsum sellae line, and inferior extension as invasion through the sellar floor into the sphenoid sinus or clivus. Categorical analysis was performed using Fisher's exact test.

RESULTS

GHPAs were overall more likely to remain purely intrasellar compared to NFPA (50% vs 26%, p < 0.001). GHPAs, however, were 7 times more likely to exhibit isolated infrasellar extension compared to NFPA (20% vs 2.8%, p = 0.001). Conversely, NFPAs were twice as likely to exhibit isolated suprasellar extension compared to GHPA (60% vs 28%, p < 0.001), as well as combined suprasellar/infrasellar extension (25% vs 3%, p = 0.011). There were no overall differences in CSI between the two subgroups.

DISCUSSION

GHPA and NFPA demonstrate distinct extrasellar extension patterns on MRI. GHPAs show proclivity for inferior extension with bony invasion, whereas NFPAs are more likely to exhibit suprasellar extension through the diaphragmatic aperture. These distinctions may have implications into the biology and future treatment of PAs.

Racial Disparities in Acromegaly and Cushing's Disease: A Referral Center Study in 241 Patients

Context

Acromegaly (ACM) and Cushing’s disease (CD) are caused by functioning pituitary adenomas secreting growth hormone and ACTH respectively.

Objective

To determine the impact of race on presentation and postoperative outcomes in adults with ACM and CD, which has not yet been evaluated.

Methods

This is a retrospective study of consecutive patients operated at a large-volume pituitary center. We evaluated (1) racial distribution of patients residing in the metropolitan area (Metro, N = 124) vs 2010 US census data, and(2) presentation and postoperative outcomes in Black vs White for patients from the entire catchment area (N = 241).

Results

For Metro area (32.4% Black population), Black patients represented 16.75% ACM (P = .006) and 29.2% CD (P = .56). Among the total 112 patients with ACM, presentations with headaches or incidentaloma were more common in Black patients (76.9% vs 31% White, P = .01). Black patients had a higher prevalence of diabetes (54% vs 16% White, P = .005), significantly lower insulin-like growth factor (IGF)-1 deviation from normal (P = .03) and borderline lower median growth hormone levels (P = .09). Mean tumor diameter and proportion of tumors with cavernous sinus invasion were similar. Three-month biochemical remission (46% Black, 55% White, P = .76) and long-term IGF-1 control by multimodality therapy (92.3% Black, 80.5% White, P = .45) were similar. Among the total 129 patients with CD, Black patients had more hypopituitarism (69% vs 45% White, P = .04) and macroadenomas (33% vs 15% White, P = .05). At 3 months, remission rate was borderline higher in White (92% vs 78% Black, P = 0.08), which was attributed to macroadenomas by logistic regression.

Conclusion

We identified disparities regarding racial distribution, and clinical and biochemical characteristics in ACM, suggesting late or missed diagnosis in Black patients. Large nationwide studies are necessary to confirm our findings.

Tumor volume improves preoperative differentiation of prolactinomas and nonfunctioning pituitary adenomas

PURPOSE

Both prolactinomas and nonfunctioning adenomas (NFAs) can present with hyperprolactinemia. Distinguishing them is critical because prolactinomas are effectively managed with dopamine agonists, whereas compressive NFAs are treated surgically. Current guidelines rely only on serum prolactin (PRL) levels, which are neither sensitive nor specific enough. Recent studies suggest that accounting for tumor volume may improve diagnosis. The objective of this study is to investigate the diagnostic utility of PRL, tumor volume, and imaging features in differentiating prolactinoma and NFA.

METHODS

Adult patients with pathologically confirmed prolactinoma (n = 21) or NFA with hyperprolactinemia (n = 58) between 2013 and 2020 were retrospectively identified. Diagnostic performance of clinical and imaging variables was analyzed using receiver-operating characteristic curves to calculate area under the curve (AUC).

RESULTS

Tumor volume and PRL positively correlated for prolactinoma (r = 0.4839, p = 0.0263) but not for NFA (r = 0.0421, p = 0.7536). PRL distinguished prolactinomas from NFAs with an AUC of 0.8892 (p < 0.0001) and optimal cut-off value of 62.45 ng/ml, yielding a sensitivity of 85.71% and specificity of 94.83%. The ratio of PRL to tumor volume had an AUC of 0.9647 (p < 0.0001) and optimal cut-off value of 21.62 (ng/ml)/cm³ with sensitivity of 100% and specificity of 82.76%. Binary logistic regression found that PRL was a significant positive predictor of prolactinoma diagnosis, whereas tumor volume, presence of cavernous sinus invasion, and T2 hyperintensity were significant negative predictors. The regression model had an AUC of 0.9915 (p < 0.0001).

CONCLUSIONS

Consideration of tumor volume improves differentiation between prolactinomas and NFAs, which in turn leads to effective management.

Long-term response to cabergoline and multi-modal treatment in men with macroprolactinoma: Does size really matter?

OBJECTIVE

To study the outcome of men with macroprolactinoma following cabergoline treatment based on tumour size.

DESIGN

Retrospective cohort study.

METHODS

The study included 94 men, divided into three groups according to adenoma diameter: 10-19 mm (Group A, n = 36); 20-39 mm (Group B, n = 41); or ≥40 mm (Group C, giant prolactinomas, n = 17). Patients were followed for a mean of 7.5 years with sellar magnetic resonance imaging, visual fields and hormone measurements.

RESULTS

Mean baseline prolactin was 767, 2090 and 24,806 ng/ml in Groups A, B and C, respectively (p < .01). Prolactin suppression below three times the upper limit of normal (ULN) was achieved in 34 (94%; mean weekly cabergoline dose of 1.2 mg), 37 (90%; cabergoline dose, 2.1 mg) and 15 (88%; cabergoline dose, 2.8 mg) men (p = .31) in each group. After excluding patients who underwent surgery and radiotherapy, cabergoline suppressed prolactin below three times ULN in 32/35 (91%), 29/37 (78%) and 11/14 (79%) men in Groups A, B and C, respectively (p = .27). Visual deficits were observed in 5 (14%), 12 (29%) and 10 (59%) patients (p < .01); improvement was achieved in 5/5 (100%), 11/12 (92%) and 10/10 (100%) of men in Groups A, B and C. Low baseline testosterone was measured in 26 (72%), 39 (95%) and 17 (100%) patients in the three groups (p < .01). Following multi-modal treatment, hypogonadism persisted in 3 (8%), 5 (12%) and 2 (12%) men, respectively (p = .85).

CONCLUSION

Macroprolactinomas in men were controlled with cabergoline in 84% of cases, independent of tumour size. Pituitary surgery and adjuvant radiotherapy further improved long-term response to 91%.

[Clinical and functional characteristics of giant pituitary adenomas in the population of patients in the Moscow region]

Benign pituitary tumors are the most common sellar neoplasms. Lesions larger than 39 mm in the maximum dimension are called giant. They are rare, and, therefore, there are few data on the clinical and morphological features of giant pituitary tumors with different hormonal activity.

AIM

The aim of this study was to identify the clinical and functional features of giant pituitary tumors with different hormonal activity.

MATERIAL AND METHODS

We analyzed data of clinical, laboratory, and instrumental examinations of 351 patients diagnosed with pituitary macroadenomas at the Moscow Regional Research Clinical Institute in the period between 2008 and 2017: there were 144 hormonally inactive pituitary adenomas and 207 hormonally active pituitary adenomas (65 prolactinomas and 142 somatotropinomas).

RESULTS AND DISCUSSION

Among 351 patients with pituitary macroadenomas, there were 32 (9.1%) giant adenoma cases: 18 (12.5%) 144 patients with hormonally inactive pituitary adenomas and 14 (6.8%) 207 patients with hormonally active pituitary adenomas 6 (3.9%) 65 prolactinomas and 6 (2.9%) 142 somatotropinomas. The volume of giant adenomas was somewhat larger among somatotropinomas 48 926 [35 067; 97 650] mm³ and prolactinomas 36 872 [15 281; 75 102] mm³ compared to that of hormonally inactive pituitary adenomas 26 933 [21 910; 42 895] mm³. Tumors had predominant suprasellar and posterosellar growth (31 (97.8%) and 29 (90.6%) cases, respectively). The most common first patient complaints were visual impairments (59.4%) and headache and/or dizziness (43.8%). Correspondingly, due to these complaints, 16 (50%) patients first consulted an ophthalmologist. Hypopituitarism detected before any treatment was present in 16 (50%) patients.

CONCLUSION

In most cases, visual impairments and headaches/dizziness were the first manifestations of giant pituitary adenomas; therefore, ophthalmologists and neurologists should always refer patients with these complaints to MRI. Patients with identified giant pituitary tumors should be referred to an endocrinologist for exclusion of hypopituitarism and, if necessary, timely prescription of hormonal therapy.

Role of prolactin/adenoma maximum diameter and prolactin/adenoma volume in the differential diagnosis of prolactinomas and other types of pituitary adenomas

The present study aimed to investigate the function of the prolactin/adenoma maximum diameter (PRL/MD) and the prolactin/adenoma volume (PRL/V) in the differential diagnosis of prolactinomas and other types of pituitary adenomas. A total of 118 patients with pituitary adenoma, hyperprolactinemia and a plasma PRL <250 µg/l were enrolled. Clinical data from these patients were retrospectively analyzed. A receiver operating characteristic curve was plotted. The function of PRL, PRL/MD and PRL/V in the differential diagnosis of prolactinomas and other types of pituitary adenomas was compared. The results revealed that a PRL of 55.65 µg/l was the most accurate [sensitivity (SE), 0.800; specificity (SP), 0.716; positive predictive value (PPV), 0.857; negative predictive value (NPV), 0.933; and Youden index (YI), 0.516]. The PRL/MD with the highest diagnostic value was 4.03 µg/(l × mm) (SE, 0.800; SP, 0.898; PPV, 0.727; NVP, 0.929; and YI, 0.698). The PRL/V with the highest diagnostic value was 54.00 µg/(l × cm³) (SE, 0.900; SP, 0.966; PPV, 0.900; NVP, 0.966; and YI, 0.866). The PRL/MD tended to be of higher diagnostic accuracy than PRL, but this difference was not statistically significant (P=0.097). The differentiation ability of PRL/V was significantly stronger than that of PRL (P=0.028). Thus, serum PRL, PRL/MD and PRL/V levels may be able to differentiate prolactinomas from other types of hyperprolactinemia-causing pituitary adenomas prior to treatment. PRL/V may be better than the PRL level in achieving a differential diagnosis, and the optimal PRL/V ratio for differentiating prolactinomas from other types of hyperprolactinemia-causing pituitary adenomas was 54.00 µg/(l × cm³).

Expression of cell cycle regulators and biomarkers of proliferation and regrowth in human pituitary adenomas

PURPOSE

The pathogenesis of pituitary adenomas (PA) is complex. Ki-67, pituitary tumour transforming gene (PTTG), vascular endothelial growth factor (VEGF), cyclin D1, c-MYC and pituitary adenylate cyclase-activating peptide (PACAP) protein expression were analysed and correlated with tumour and patient characteristics.

METHODS

74 pituitary tumour samples (48 non-functional PA, 26 functional PAs); Immunohistochemical analysis of protein expression, retrospective analysis of MR images and in vitro analysis of octreotide treatment was carried out on GH3 cells.

RESULTS

PTTG expression was negatively associated with age and positively with PA size, regrowth and Ki-67 index. Cyclin D1 correlated with Ki-67 and tumour size. c-MYC negatively correlated with size of tumour and age; and correlated with PTTG expression. Somatostatin analogue treatment was associated with lower Ki-67, PTTG and Cyclin D1 expression while T2 hypointense PAs were associated with lower PTTG, cyclin D1, c-MYC and Ki-67. In vitro analyses confirmed the effect of somatostatin analogue treatment on Pttg and Cyclin D1 expression.

CONCLUSIONS

Interesting and novel observations on the differences in expression of tumour markers studied are reported. Correlation between Ki-67 expression, PTTG nuclear expression and recurrence/regrowth of PAs, emphasizes the role that Ki-67 and PTTG expression have as markers of increased proliferation. c-MYC and PTTG nuclear expression levels were correlated providing evidence that PTTG induces c-MYC expression in PAs and we propose that c-MYC might principally have a role in early pituitary tumorigenesis. Evidence is shown that the anti-proliferative effect of somatostatin analogue treatment in vivo occurs through regulation of the cell cycle.