Neurogenic myocardial dysfunction post craniopharyngioma resection: A diagnostic dilemma

Endoscopic transsphenoidal resection of craniopharyngioma is a commonly used technique. Cerebral vasospasm may occur in nearly 10% of cases leading to adverse neurological outcomes. Cardiopulmonary dysfunction may be seen in patients with severe vasospasm. The literature describing the occurrence of neurogenic stunned myocardium following craniopharyngioma resection in pediatric patients is very sparse. Here, we describe such a case managed with a combination of milrinone (to relieve vasospasm and improve cardiac pump function), noradrenaline (to obtain target blood pressure), and vasopressin (to control urine output). This case report proposes the treatment plan of neurogenic stunned myocardium following vasospasm in pediatric patients.

Italian Association of Clinical Endocrinologists (AME) and International Chapter of Clinical Endocrinology (ICCE). Position statement for clinical practice: prolactin-secreting tumors

Prolactinomas are the most frequent pituitary adenomas. Prolactinoma may occur in different clinical settings and always require an individually tailored approach. This is the reason why a panel of Italian neuroendocrine experts was charged with the task to provide indications for the diagnostic and therapeutic approaches that can be easily applied in different contexts. The document provides 15 recommendations for diagnosis and 54 recommendations for treatment, issued according to the GRADE system. The level of agreement among panel members was formally evaluated by RAND-UCLA methodology. In the last century, prolactinomas represented the paradigm of pituitary tumors for which the development of highly effective drugs obtained the best results, allowing to avoid neurosurgery in most cases. The impressive improvement of neurosurgical endoscopic techniques allows a far better definition of the tumoral tissue during surgery and the remission of endocrine symptoms in many patients with pituitary tumors. Consequently, this refinement of neurosurgery is changing the therapeutic strategy in prolactinomas, allowing the definitive cure of some patients with permanent discontinuation of medical therapy.

Downregulation of miR-216a-5p and miR-652-3p is associated with growth and invasion by targeting JAK2 and PRRX1 in GH-producing pituitary tumours

Expression of aberrant microRNA (miRNA) is associated with tumour formation, migration, and invasion. However, there is limited information about the epigenetics of pituitary tumorigenesis. This study investigated the role of miRNA expression during the tumorigenesis of growth hormone (GH)-secreting pituitary tumours. miRNA profiling and real-time PCR were used to analyse the mRNA expression profile in sequential pituitary tissues of a unique animal model with a GH-producing pituitary tumour. Selected miRNAs were further validated in GH-producing cell lines and human pituitary tumour samples. The expression of significantly altered miRNAs and their predicted targets, as detected by microarray, was evaluated by real-time PCR, Western blotting, and immunohistochemistry using samples from mouse models and human pituitary tumours. The effect of miRNAs on tumour proliferation and invasion was examined in GH3 cells using the MTS and Matrigel invasion assays. Among the 14 miRNAs whose expression was significantly changed, miR-216a-5p (fold change = -5.638, P -value = 0.014) and miR-652-3p (fold change = -3.482, P -value = 0.010) were constantly and significantly downregulated. Transfection with mimics of miR-216a-5p and miR-652-3p inhibited GH3 proliferation and invasion, whereas inhibitors promoted them. The direct target genes of miR-216a-5p and miR-652-3p were Jak2 and Prrx1, respectively, which were downregulated in GH3 cells transfected with mimics and in serial pituitary gland tissues, including hyperplasic tissues and tumours of acromegalic animal models and pituitary tumour tissues of acromegalic patients. Downregulated miR-216a-5p and miR-652-3p expression may contribute to tumour progression by targeting JAK2 and PRRX1 on GH-producing pituitary tumours.

Growth hormone secreting pituitary carcinomas: Case report and review of literature

OBJECTIVE

Pituitary carcinoma is a rare tumor, defined as a tumor of adenohypophyseal cells with systemic or craniospinal metastasis. We present a case of a growth hormone (GH)-secreting pituitary carcinoma with a review of literature to better characterize this disease.

DESIGN

Case report and literature review of 25 cases of GH-secreting pituitary carcinomas RESULTS: The age of diagnosis of GH-secreting carcinomas ranged 24-69 years old with a mean age of 44.4 with 52% of cases present in females. Mean latency period between diagnosis of acromegaly and transition to pituitary carcinoma was 11.4 years with mean survival being 3.4 years.

CONCLUSION

Growth hormone (GH)-secreting pituitary carcinomas are rare and hard to distinguish from aggressive pituitary adenomas. From review of literature, treatment options include debulking surgery, radiotherapy, or chemotherapy with dismal outcomes. There are no diagnostic markers or features which can predict metastatic progression of these tumors. Future studies with genomic landscapes and relevant tumor markers are needed to identify pituitary tumors most likely to metastasize.

Clinical and Molecular Update on Genetic Causes of Pituitary Adenomas

Pituitary adenomas are benign tumors with variable functional characteristics that can have a significant impact on patients. The majority arise sporadically, but an inherited genetic susceptibility is increasingly being recognized. Recent advances in genetics have widened the scope of our understanding of pituitary tumorigenesis. The clinical and genetic characteristics of pituitary adenomas that develop in the setting of germline-mosaic and somatic GNAS mutations (McCune-Albright syndrome and sporadic acromegaly), germline MEN1 mutations (multiple endocrine neoplasia type 1), and germline PRKAR1A mutations (Carney complex) have been well described. Non-syndromic familial cases of isolated pituitary tumors can occur as familial isolated pituitary adenomas (FIPA); mutations/deletions of the AIP gene have been found in a minority of these. Genetic alterations in GPR101 have been identified recently as causing X-linked acro-gigantism (X-LAG) leading to very early-onset pediatric gigantism. Associations of pituitary adenomas with other tumors have been described in syndromes like multiple endocrine neoplasia type 4, pheochromocytoma-paraganglioma with pituitary adenoma association (3PAs) syndrome and some of their genetic causes have been elucidated. The genetic etiologies of a significant proportions of sporadic corticotropinomas have recently been identified with the discovery of USP8 and USP48 mutations. The elucidation of genetic and molecular pathophysiology in pituitary adenomas is a key factor for better patient management and effective follow-up.

Biochemical Control in Acromegaly With Multimodality Therapies: Outcomes From a Pituitary Center and Changes Over Time

PURPOSE

To determine the prevalence of insulin-like growth factor-1 (IGF-1) normalization with long-term multimodality therapy in a pituitary center and to assess changes over time.

METHODS

Patients with acromegaly (N = 409), with ≥1 year of data after surgery and at least 2 subsequent clinic visits were included in long-term analysis (N = 266). Biochemical data, clinical characteristics, and therapeutic interventions were reviewed retrospectively.

RESULTS

At diagnosis, mean [standard deviation] age was 43.4 [14.3] years, body mass index was 28.5 (24.9-32.1) kg/m2 (median, interquartile range), serum IGF-1 index (IGF-1 level/upper limit of normal) was 2.3 [1.7-3.1], and 80.5% had macroadenomas. Patients with transsphenoidal surgery after 2006 were older [46.6 ± 14.3 vs 40.0 ± 13.4 years; P < 0.001]. Age and tumor size correlated inversely. Overall (N = 266), 93.2% achieved a normal IGF-1 level during 9.9 [5.0-15.0] years with multimodality therapy. The interval to first normal IGF-1 level following failed surgical remission was shorter after 2006: 14.0 (95% confidence interval, 10.0-20.0) versus 27.5 (22.0-36.0) months (P = 0.002). Radiation therapy and second surgery were rarer after 2006: 28 (22%) versus 62 (47.0%); P < 0.001 and 12 (9.4%) versus 28 (21.2%); P = 0.010, respectively. Age at diagnosis increased over time periods, possibly reflecting increased detection of acromegaly in older patients with milder disease. Male gender, older age, smaller tumor and lower IGF-1 index at diagnosis predicted long-term sustained IGF-1 control after surgery without adjuvant therapies.

CONCLUSION

The vast majority of patients with acromegaly can be biochemically controlled with multimodality therapy in the current era. Radiotherapy and repeat pituitary surgery became less frequently utilized over time. Long-term postoperative IGF-1 control without use of adjuvant therapies has improved.

Pituitary adenoma secondary to primary hypothyroidism: Two case reports

RATIONALE

Primary hypothyroidism is characterized by loss of thyroxine feedback inhibition and overproduction of thyrotropin-releasing hormone, which might result in reactive pituitary hyperplasia. However, pituitary adenoma secondary to primary hypothyroidism is extremely rare and usually underdiagnosed, and the pathogenic mechanism remains unclear. Herein, we reported two cases with pituitary adenoma secondary to primary hypothyroidism.

PATIENT CONCERNS

Case 1: A 35-year-old man presented to the local clinic with a 2-year history of fatigue, puffiness in the bilateral lower extremities and facial region, and coarseness of facial features. Additionally, his relatives also supplemented that he suffered from hypomnesis and hypophrenia.Case 2: A 56-year-old, postmenopausal woman presented to the local clinic with fatigue, dry skin, and sluggishness.

DIAGNOSES

The pathological diagnosis of two patients was plurihormonal pituitary adenoma.

INTERVENTIONS

A microscopical tumorectomy was performed when the two patients were admitted to our hospital. Thyroid hormone replacement therapy (thyroxine 50 μg/day) was prescribed after microsurgery.

OUTCOMES

After 32 months (Case 1) or 43 months (Case 2) follow-up respectively, there was no recurrence, and the symptoms were completely relieved.

LESSONS

Pituitary hyperplasia caused by primary hypothyroidism responds well to thyroid hormone replacement therapy. It is worth noting that repeated detection of serum T3, T4, and thyroid-stimulating hormone (TSH) should be performed 3 months after replacement therapy. If the results showed that TSH level decreased partly, while thyroid function did not improve significantly, long-term increased secretion of pituitary TSH adenoma should be considered. And microsurgical resection via a transsphenoidal approach could be ordered. If the optic nerve or optic chiasm were pressed by the adenoma, microsurgery should be performed to relieve the pressure immediately. And then, thyroxine tablet substitute therapy should be performed after surgery.

Genetic and Epigenetic Causes of Pituitary Adenomas

Pituitary adenomas (PAs) can be classified as non-secreting adenomas, somatotroph adenomas, corticotroph adenomas, lactotroph adenomas, and thyrotroph adenomas. Substantial advances have been made in our knowledge of the pathobiology of PAs. To obtain a comprehensive understanding of the molecular biological characteristics of different types of PAs, we reviewed the important advances that have been made involving genetic and epigenetic variation, comprising genetic mutations, chromosome number variations, DNA methylation, microRNA regulation, and transcription factor regulation. Classical tumor predisposition syndromes include multiple endocrine neoplasia type 1 (MEN1) and type 4 (MEN4) syndromes, Carney complex, and X-LAG syndromes. PAs have also been described in association with succinate dehydrogenase-related familial PA, neurofibromatosis type 1, and von Hippel-Lindau, DICER1, and Lynch syndromes. Patients with aryl hydrocarbon receptor-interacting protein (AIP) mutations often present with pituitary gigantism, either in familial or sporadic adenomas. In contrast, guanine nucleotide-binding protein G(s) subunit alpha (GNAS) and G protein-coupled receptor 101 (GPR101) mutations can lead to excess growth hormone. Moreover, the deubiquitinase gene USP8, USP48, and BRAF mutations are associated with adrenocorticotropic hormone production. In this review, we describe the genetic and epigenetic landscape of PAs and summarize novel insights into the regulation of pituitary tumorigenesis.

Association of PTTG1 polymorphism rs1895320, rs2910200 and rs6882742 with non-functioning pituitary adenomas in Chinese Han population: a case-control study

Due to absence of clinical manifestations of hormonal hyper secretion, the treatment of Nonfunctioning pituitary adenoma (NFPA) was always delayed. PTTG1 was reported to be overexpressed in most of pituitary tumors, however, the polymorphism of PTTG1 rs1895320, rs2910200 and rs6882742 with NFPA were still not fully elucidated in NFPA. Thus, a hospital based case control study which included 79 patients and 142 healthy control participants were conducted. DNA was extracted from peripheral blood samples and genotyped by Mass Array methods. In addition, a meta-analysis of rs2910200 was also employed to further testify the conclusion. Significant difference were observed between patients and healthy controls under rs2910200 locus between allelic genotype (p = 0.0219). However, no other significant difference was observed in rs1895329 and rs6882742. In addition, a logistic regression analysis showed that the dominant model of rs2910200 were closely correlated with the NFPA susceptibility (OR = 1.951, 95% CI:1.075-3.542, p = 0.028). While no significant difference was observed in the rs1895320 and rs6882742 under dominant model, recessive model and additive model The meta-analysis results showed that the dominant model and heterozygote model can significantly increase the risk of PA (p = 0.007, OR = 1.57, 95% CI:1.14-2.18; p = 0.009, OR = 1.57, 95% CI:1.12-2.19). Whereas no significant difference were observed under the homozygous model and recessive model. In conclusion, the polymorphism of PTTG1 rs2910200 dominant model and T allelic might increase the risk of NFPA.

mPRs represent a novel target for PRL inhibition in experimental prolactinomas

Membrane progesterone receptors are known to mediate rapid nongenomic progesterone effects in different cell types. Recent evidence revealed that mPRα is highly expressed in the rat pituitary, being primarily localized in lactotrophs, acting as an intermediary of P4-inhibitory actions on prolactin secretion. The role of mPRs in prolactinoma development remains unclear. We hypothesize that mPR agonists represent a novel tool for hyperprolactinemia treatment. To this end, pituitary expression of mPRs was studied in three animal models of prolactinoma. Expression of mPRs and nuclear receptor was significantly decreased in tumoral pituitaries compared to normal ones. However, the relative proportion of mPRα and mPRβ was highly increased in prolactinomas. Interestingly, the selective mPR agonist (Org OD 02-0) significantly inhibited PRL release in both normal and tumoral pituitary explants, displaying a more pronounced effect in tumoral tissues. As P4 also regulates PRL secretion indirectly, by acting on dopaminergic neurons, we studied mPR involvement in this effect. We found that the hypothalamus has a high expression of mPRs. Interestingly, both P4 and OrgOD 02-0 increased dopamine release in hypothalamus explants. Moreover, in an in vivo treatment, that allows both, pituitary and hypothalamus actions, the mPR agonist strongly reduced the hyperprolactinemia in transgenic females carrying prolactinoma. Finally, we also found and interesting gender difference: males express higher levels of pituitary mPRα/β, a sex that does not develop prolactinoma in these mice models. Taken together, these findings suggest mPRs activation could represent a novel tool for hyperprolactinemic patients, especially those that present resistance to dopaminergic drugs.

Nonalcoholic fatty liver disease with prolactin-secreting pituitary adenoma in an adolescent: A case report

RATIONALE

Nonalcoholic fatty liver disease (NAFLD), among the commonest chronic liver disorders in children and adolescents, is considered a reflection of the current obesity epidemic in children and adults. This liver disease has been linked with various metabolic disorders, but not with prolactinoma (PRLoma).

PATIENT CONCERNS

A 13-year-old Japanese girl manifested obesity, serum transaminase and γ-glutamyltransferase elevations, and amenorrhea. Abdominal ultrasonography showed fatty liver. Her serum prolactin concentration was elevated, and cranial magnetic resonance imaging showed a pituitary mass consistent with macroadenoma.

DIAGNOSES

NAFLD and PRLoma.

INTERVENTIONS AND OUTCOMES

After the patient's NAFLD failed to respond to diet and exercise, cabergoline treatment of the PRLoma decreased body weight, serum transaminase and γ-glutamyltransferase elevations, and ultrasonographic fatty liver grade as the tumor became smaller.

LESSONS

Physicians should consider the possibility of PRLoma when diet and exercise fail to improve fatty liver disease in a patient with endocrine symptoms such as amenorrhea.

Pituitary acromegaly: not one disease

Acromegaly has traditionally been regarded as a monomorphous disorder resulting from a benign pituitary adenoma. Increasing evidence, however, is highlighting that this disorder is associated with a spectrum of morphologically distinct pituitary tumors with variable clinical, biochemical and radiologic features and differing therapeutic outcomes that are attributed to different genetic and epigenetic changes. These data underscore the need for developing a more refined clinicopathological risk stratification system and implementing personalized targeted therapeutic approaches.

Turner syndrome and pituitary adenomas: a case report and review of literature

BACKGROUND

Turner syndrome (TS) is the most common sex chromosome abnormality in females, typically associated with primary amenorrhea and premature ovarian failure due to gonadal dysgenesis. The association of TS with hypopituitarism is an uncommon finding. The objective of the study was to describe an adolescent with TS with hypergonadotropic hypogonadism and subsequent hypogonadotropic hypogonadism.

CASE PRESENTATION

A 16-year-old female with primary amenorrhea was diagnosed with TS based on karyotype 45,XO. Other laboratory values included FSH 45.52 IU/L, LH 17.4 IU/L, undetectable estradiol, and prolactin 1.08 nmol/L. Two months later and before treatment, she presented with severe headache and a new left cranial nerve VI palsy. Brain MRI showed a 2.7-cm hemorrhagic pituitary macroadenoma expanding the sella. Laboratory evaluation showed FSH 5.9 IU/L, LH 0.9 IU/L, prolactin 0.09 nmol/L, and GH 1.03 ng/mL. She underwent transphenoidal hypophysectomy, and pathology revealed pituitary adenoma with immunohistochemical staining positive for growth hormone and prolactin. She subsequently developed multiple pituitary hormone deficiencies. Review of the literature identified eight case reports of women with TS who developed pituitary adenomas.

CONCLUSIONS

This case illustrates an uncommon co-occurrence of TS and pituitary macroadenoma. Sequential gonadotropin measurements demonstrate the evolution of hypergonadotropic hypogonadism into hypogonadotropic hypogonadism due to hemorrhagic pituitary macroadenoma.

Negative correlation between tumour size and cortisol/ACTH ratios in patients with Cushing's disease harbouring microadenomas or macroadenomas

PURPOSE

Pituitary macroadenomas (MACs) represent 10-30 % of Cushing's disease (CD) cases. The aim of this study was to report the clinical, laboratorial and imaging features and postsurgical outcomes of microadenoma (MIC) and MAC patients.

METHODS

Retrospective study with 317 CD patients (median 32 years old, range 9-71 years) admitted between 1990 and 2014, 74 (23.3 %) of whom had MAC.

RESULTS

Hirsutism, plethora facial, muscular weakness and muscular atrophy were more frequent in the MIC patients. Nephrolithiasis, osteopenia, hyperprolactinaemia and galactorrhoea were more prevalent in MAC patients. The morning serum cortisol (Fs), nocturnal salivary cortisol (NSC), nocturnal Fs (Fs 2400 h), low- and high-dose dexamethasone suppression test results and CRH and desmopressin test results were similar between the subgroups. MIC patients showed higher urinary cortisol at 24 h (UC), and MAC patients presented higher ACTH levels but lower Fs/ACTH, Fs 2400 h/ACTH, NSC/ACTH and UC/ACTH ratios. There were negative correlations of tumour size with Fs/ACTH, Fs 2400 h/ACTH, NSC/ACTH and UC/ACTH ratios. Overall, the postsurgical remission and recurrence rates were similar between MIC and MAC. However, patients in remission (MIC + MAC) showed smaller tumour diameters and a lower prevalence of invasion and extension on MRI.

CONCLUSIONS

Despite exhibiting higher plasma ACTH levels, CD patients with MAC presented lower cortisol/ACTH ratios than did patients with MIC, with a negative correlation between tumour size and cortisol/ACTH ratios. The overall postsurgical remission and recurrence rates were similar between MIC and MAC patients, with those with larger and/or invasive tumours showing a lower remission rate.

Assessment of Environmental and Hereditary Influence on Development of Pituitary Tumors Using Dermatoglyphic Traits and Their Potential as Screening Markers

The aim of this study was to assess environmental and hereditary influence on development of pituitary tumors using dermatoglyphic traits. The study was performed on 126 patients of both genders with pituitary tumors (60 non-functional and 66 functional pituitary tumor patients) in comparison to the control group of 400 phenotypically healthy individuals. Statistical analysis of quantitative and qualitative traits of digito-palmar dermatoglyphics was performed, and hormonal status was determined according to the standard protocols. Although we did not find markers that could specifically distinguish functional from non-functional tumors, we have found markers predisposing to the development of tumors in general (a small number of ridges between triradius of both hands, a smaller number of ridges between the triradius of c–d rc R), those for endocrine dysfunction (increased number of arches and reduced number of whorls, difference of pattern distribution in the I3 and I4 interdigital space), and some that could potentially be attributed to patients suffering from pituitary tumors (small number of ridges for variables FRR 5, smaller number of ridges in the FRL 4 of both hands and difference of pattern distribution at thenar of I1 and I2 interdigital space). The usage of dermatoglyphic traits as markers of predisposition of pituitary tumor development could facilitate the earlier detection of patients in addition to standard methods, and possibly earlier treatment and higher survival rate. Finally, our results are consistent with the hypothesis about multifactorial nature of pituitary tumor etiology comprised of both gene instability and environmental factors.

Pituitary Medicine From Discovery to Patient-Focused Outcomes

CONTEXT

This perspective traces a pipeline of discovery in pituitary medicine over the past 75 years.

OBJECTIVE

To place in context past advances and predict future changes in understanding pituitary pathophysiology and clinical care.

DESIGN

Author's perspective on reports of pituitary advances in the published literature.

SETTING

Clinical and translational Endocrinology.

OUTCOMES

Discovery of the hypothalamic-pituitary axis and mechanisms for pituitary control, have culminated in exquisite understanding of anterior pituitary cell function and dysfunction. Challenges facing the discipline include fundamental understanding of pituitary adenoma pathogenesis leading to more effective treatments of inexorably growing and debilitating hormone secreting pituitary tumors as well as medical management of non-secreting pituitary adenomas. Newly emerging pituitary syndromes include those associated with immune-targeted cancer therapies and head trauma.

CONCLUSIONS

Novel diagnostic techniques including imaging genomic, proteomic, and biochemical analyses will yield further knowledge to enable diagnosis of heretofore cryptic syndromes, as well as sub classifications of pituitary syndromes for personalized treatment approaches. Cost effective personalized approaches to precision therapy must demonstrate value, and will be empowered by multidisciplinary approaches to integrating complex subcellular information to identify therapeutic targets for enabling maximal outcomes. These goals will be challenging to attain given the rarity of pituitary disorders and the difficulty in conducting appropriately powered prospective trials.

[Multiple Endocrine Neoplasia I (Wermers Syndrome), Forms of Clinical Manifestation, 5 Case Studies]

Multiple Endocrine Neoplasia (MEN) is a condition in which several endocrine organs of an individual are affected by adenoma, hyperplasia and less often carcinoma, either simultaneously or at different stages of life. Two existing syndromes, MEN1 and MEN2 (2A, 2B), in literature is also mentioned MEN4, are associated also with other non-endocrine disorders. MEN1 (Wermer syndrome) affects the pituitary, parathyroid, and pancreatic area. 95 % of patients show very early manifestation of hyperparathyroidism, often before 40 years of age. Multiple adenomas gradually involve all four parathyroid glands. The first clinical sign of MEN1 includes recurrent nephrolithiasis. The second most frequent manifestation of MEN1 is pancreatic area (pancreas, stomach and duodenum), again multiple malignancies of varying degree which can metastasize. Most often gastrinomas and insulinomas are involved. Pituitary adenomas occur in about one third of MEN1 patients and tend to be larger and less responsive to treatment. Tumors appearing most often are prolactinomas, tumors producing growth hormone, or afunctional adenomas. The other endocrine tumors include carcinoids and adrenal lesions. In the last year we have registered four MEN1 syndrome patients in our center and one patient has been already followed since 2008. In four out of five patients, nephrolithiasis after 30 years of age was the first clinical symptom, but only one of theses cases resulted in MEN1 diagnosis. In all patients, the clinical symptoms intensified and the diagnosis was established between 36 and 40 years of age. A crutial factor is a cooperation with the urology examination of kidney stones formation in young individuals with nephrolithiasis in order to reveal the potential cases of MEN1 syndrome very early on. Consider the MEN1 genetic diagnostics if recurrent primary hyperparathyroidism or recurrent gastroduodenal ulcer disease appear in patients under 40 years of age.Key words: carcinoid - gastrinoma - hyperparathyroidism - insulinoma - MEN1 - multiple endocrine neoplasia - nefrolithiasis - neuroendocrine tumor - pancreatic area - pituitary gland.

Targeted BRAF and CTNNB1 next-generation sequencing allows proper classification of nonadenomatous lesions of the sellar region in samples with limiting amounts of lesional cells

PURPOSE

To assess the role of high sensitivity next-generation sequencing (NGS) of CTNNB1 for the diagnosis of adamantinomatous craniopharyngiomas (aCPs) and of BRAF for that of papillary CPs (pCPs) in routinely processed surgical samples of non-adenomatous sellar lesions.

METHODS

Forty-five cases of patients operated for non-adenomatous masses of the sellar region between 2004 and 2014 were retrieved from the files of the Anatomic Pathology unit of the Bellaria Hospital in Bologna, Italy. BRAF and CTNNB1 mutation status was analyzed by NGS in samples smaller than 1 cm(3) and histological re-evaluation was performed on all cases.

RESULTS

CTNNB1 mutation analysis showed a sensitivity of 86.7 % and a specificity of 96.2 % for the diagnosis of aCPs. The specificity increased to 100 % considering that in one case, initially classified as a non-CP lesion (xanthogranuloma), the identification of a CTNNB1 S47R lead to histological re-evaluation and reclassification of the lesion as aCP. BRAF mutation analysis had a sensitivity of 76.9 % and a specificity of 96.4 % for the diagnosis of pCPs. The specificity increased to 100 % considering that in one case, initially classified as a Rathke cyst, the identification of BRAF V600E lead to histological re-evaluation and reclassification of the lesion as pCP.

CONCLUSIONS

This study confirms the diagnostic relevance of the molecular alterations recently identified in aCPs and pCPs and shows how the identification of BRAF and CTNNB1 mutations can be instrumental for the proper classification of samples that contain limiting amounts of diagnostic lesional tissue.

The role of diabetes in acromegaly associated neoplasia

Background

The risk and mortality due to cancer in patients with acromegaly have been previously investigated. Although GH/IGF-1 excess provides a probable pathophysiological explanation, the degree of IGF-1 excess and the role in acromegaly-associated neoplasms of diabetes, a common comorbidity in acromegaly with known association with cancer, remains unclear.

Methods

Acromegalic patients treated in three Canadian referral centers (Toronto, Montreal, Edmonton) were included. All available clinical information was recorded including: age, initial and last percentage of the upper limit of normal (%ULN) IGF-1 levels, comorbidities and other neoplasms (benign and malignant).

Results

408 cases were assessed. 185 were women (45.3%), 126 (30.9%) developed extra-pituitary neoplasms: 55 malignant and 71 benign. The most frequent anatomic site was the gastrointestinal tract (46 [11.3%]), followed by head and neck (36 [8.8%]) and multiple locations (14 [3.4%]). 106 (26.0%) cases had diabetes. Initial IGF-1 was significantly higher in men older than 50 (380.15 vs. 284.78, p = 0.001) when compared to men younger than 50. Diabetics showed significantly higher initial IGF-1 (389.38 vs. 285.27, p = 0.009), as did diabetics older than 50 compared with those without diabetes. 45.3% (48/106) of cases with diabetes developed extra-pituitary neoplasms vs. 24.3% (71/292) without diabetes (p = 0.001, OR: 2.576 95%CI 1.615–4.108). 22.6% (24/106) of cases with diabetes developed malignant tumors vs. 9.2% (27/292), (p < 0.001, OR 2.873, 95%CI 1.572–5.250).

Conclusions

These data suggest that acromegalic patients with diabetes are more likely to develop extra-pituitary neoplasms and their initial IGF-1 levels are higher. The contribution of IGF-1 vs. diabetes alone or in combination in the development of extra-pituitary neoplasms warrants further investigation.

Menopausal hormone therapy and central nervous system tumor risk: large UK prospective study and meta-analysis

Female sex hormones are thought to affect women's risk of developing central nervous system (CNS) tumors. Some have reported an increased risk in users of menopausal hormone therapy (HT) but evidence is limited. In the UK General Practice Research Database we compared prospectively collected information on HT prescriptions in women aged 50-79 years with CNS tumors diagnosed in 1987-2011 with that in matched controls (four per case). Relative risks (RRs) in relation to prescribed HT were calculated overall and by CNS tumor subtype. Statistical tests are two-sided. For all CNS tumors (n = 3,500), glioma (n = 689), meningioma (n = 1,197), acoustic neuroma (n = 439), and pituitary tumors (n = 273) adjusted RRs for women prescribed HT versus not were, respectively, 1.21 (95% confidence intervals (CI) = 1.10-1.32, p < 0.0001), 1.14 (0.93-1.40, p = 0.2), 1.30 (1.11-1.51, p = 0.001), 1.37 (1.06-1.75, p = 0.01), and 1.35 (0.99-1.85, p = 0.06). There was no significant difference in risk by tumor subtype (p(heterogeneity) = 0.6). A meta-analysis was conducted, combining our results with those from other published studies with prospectively collected exposure information. The meta-analyses yielded significantly increased risks for all CNS tumors, glioma and meningioma in users of estrogen-only [1.35 (1.22-1.49), 1.23 (1.06-1.42) and 1.31 (1.20-1.43), respectively] but not estrogen-progestin HT [1.09 (0.99-1.19), 0.92 (0.78-1.08) and 1.05 (0.95-1.16), respectively]; these differences were statistically significant (p < 0.005 for each tumor type). There was no significant difference between glioma and meningioma risk in users of estrogen-only HT. The totality of the available evidence suggests an increased risk of all CNS tumors (and of glioma and meningioma separately) in users of estrogen-only HT. Absolute excess risk (2 per 10,000 users over 5 years) is small.

A 7 years old girl with abdominal lump and per-vaginal bleeding of hypothyroidism

Hypothyroidism is a common endocrine disorder resulting from decreased secretion of thyroid hormone. The diagnosis of hypothyroidism is suggested from the clinical and laboratory findings. Here we present a case report on this disease with rare presentation of abdominal lump and pervaginal bleeding in childhood. A 7 years old girl admitted in a tertiary level hospital with abdominal lump and irregular per vaginal bleeding. Abdominal swelling was gradually increasing in size & associated with lower abdominal pain for last 5 months. On examination the girl was moderately anaemic, mildly oedematous, distended lower abdomen and a mass in left iliac region. Her thyroid function test, serum FSH, serum LH, serum Prolactin was done and high FSH, LH, Prolactin levels were found. Ultrasonography of lower abdomen revealed bulky uterus and bilateral ovarian cysts. MRI of Brain showed feature of pituitary microadenoma. Finally the patient was diagnosed as primary hypothyroidism and bilateral follicular ovarian cyst with pituitary adenoma developed as its consequence. The case is reported for clinical awareness & to share our experience.

Outcome of prolactinoma after pregnancy and lactation: a study on 73 patients

CONTEXT

Prolactinoma is the most frequent pituitary tumour among women of child-bearing age. Only a few studies have addressed the outcome of prolactinoma after pregnancy.

OBJECTIVE

To study remission, defined as prolactin normalization without medical treatment, after pregnancy and lactation in women with prolactinoma.

PATIENTS AND METHODS

A retrospective study conducted in 2 Belgian academic centres including 73 patients (54 microprolactinomas and 19 macroprolactinomas) with 104 pregnancies continuing beyond first trimester. Dopamine agonists were stopped in early pregnancy in all treated cases. Prolactin level and adenoma size at pituitary magnetic resonance imaging (MRI) were recorded before pregnancy and throughout follow-up.

RESULTS

Thirty of 73 women (41%) were in remission after a median follow-up of 22 months after delivery or cessation of lactation. Adenoma size at diagnosis was smaller in women in remission (5 vs 8 mm). There was a nonsignificant higher rate of remission for microprolactinomas than for macroprolactinoma (46% vs 26%). The first pituitary MRI after pregnancy and lactation showed no tumour and a decreased adenoma size in 23% and 39% of women, respectively. MRI normalization was associated with remission. The number of pregnancies per woman as well as breastfeeding and its duration did not influence remission rate.

CONCLUSION

More than 40% of women with previous diagnosis of prolactinoma have normal PRL level without medical treatment for a median follow-up of 22 months after pregnancy and lactation. The likelihood of remission is associated with a smaller initial adenoma size and normalization of pituitary MRI after pregnancy.

Pituitary adenomas in childhood and adolescence

Scientific advances are revealing the complexity of pituitary development, which is controlled by multiple transcription factors and signaling molecules. Unregulated pituitary cell growth, resulting in pituitary adenoma, is usually sporadic and results from monoclonal expansion of a single mutated cell. However, some adenomas develop as part of a genetic syndrome. Prolactinoma is the most common hormonally active pituitary adenoma in children. The non-functioning (non-secreting) pituitary adenoma is the second most common and often stains positive for GH, PRL, and/or TSH. While Cushing disease, resulting from an ACTH-secreting adenoma, commonly manifests as weight gain with growth deceleration in children, GH excess causes gigantism with rapid, accelerated growth inappropriate for the height of the family. TSH secreting pituitary adenomas are rare, and biochemical analysis will show an elevated thyroxine level with a non-suppressed or high TSH. Though the natural history of pituitary incidentalomas in children is unknown, adult practice guidelines are established.

Pituitary stalk lesions: the Mayo Clinic experience

CONTEXT

Pituitary stalk lesions have various etiologies, often not clinically apparent. Pathological samples from these lesions are rarely obtained, because of the critical location and function of the hypophyseal stalk.

OBJECTIVES

The purpose of this study was to characterize the etiological spectrum of pituitary stalk lesions seen at Mayo Clinic Rochester over 20 years and to determine whether specific magnetic resonance imaging (MRI) characteristics could provide clinician guidance with regard to the etiology of infundibular lesions.

DESIGN

A retrospective review of patients with pituitary stalk lesions seen at Mayo Clinic Rochester between 1987 and 2006 was conducted. Demographic, clinical presentation, imaging, laboratory, operative, and pathology data were reviewed and are reported using descriptive statistics.

RESULTS

Of the 152 pituitary stalk lesions included, 49 (32%) were neoplastic, 30 (20%) were inflammatory, 13 (9%) were congenital anomalies, and 60 (39%) were of unclear etiology. Diabetes insipidus was diagnosed in 43 (28%) of the 152 patients, and 49 (32%) patients had at least one anterior pituitary hormone deficit. Secondary hypogonadism was the most common endocrine deficiency. Eleven of 13 congenital lesions were round in appearance and 5 of 7 patients with neurosarcoidosis confirmed by pathology had a uniformly thickened pituitary stalk on MRI. There were no statistically significant correlations between hypopituitarism and the pattern of enhancement or size of the lesion.

CONCLUSIONS

Findings on MRI remain key in guiding the diagnosis of pituitary stalk lesions, particularly when used in conjunction with other clinical clues. There are no good imaging predictors for hypopituitarism, making clinical evaluation of all patients with pituitary stalk lesions crucial.

Pathology and pathogenesis of craniopharyngiomas

Craniopharyngiomas are benign but locally invasive tumours of the sellar region that occur as two subtypes. The adamantinomatous type (aCP) occurs mainly during childhood while the papillary type (pCP) is found almost exclusively in adults. It is thought that aCPs arise from ectopic embryonic remnants of Rathke's pouch and these tumours share features with odontogenic tumours suggesting a common origin. The pathogenesis of pCPs is less understood but these tumours may arise from metaplastic transformation of anterior pituitary epithelial cells. Mutations in CTNNB1 that encodes β-catenin are found in around 70 % of aCPs. These mutations stabilise β-catenin, which evades destruction and accumulates in the nucleus and cytosol leading to constitutive activation of the Wnt signaling pathway. Expression of mutant β-catenin early in mouse pituitary development promotes the formation of tumours similar to aCPs. However, accumulation of β-catenin occurs only in small clusters of tumour cells even though the mutation is ubiquitous. These cell clusters are slow-growing and share some characteristics with pituitary stem cells. They are often present at the invading edge and express growth factors that may participate in paracrine signaling to surrounding cells. β-Catenin nuclear translocation may also occur in the absence of CTNNB1 mutations, suggesting that other genetic or epigenetic events can activate Wnt signaling in aCP. These mechanisms, as well as those underlying the molecular pathogenesis of pCPs remain to be identified.

Wegener granulomatosis as an uncommon cause of panhypopituitarism in childhood

Wegener granulomatosis (WG) is a cytoplasmic antineutrophil cytoplasmic antibody (c-ANCA)-associated, multi-system, necrotizing granulomatous vasculitis. Inflammation of the nasal or oral mucosa, and lung and kidney involvements are typical in the course of the disease. In rare cases, pituitary involvement may occur and cause panhypopituitarism. Pituitary involvement is very rare, and only two pediatric case reports have been published to date out of a total of 24 cases. This is a case report of an adolescent patient who presented with panhypopituitarism symptoms and was later diagnosed with WG. A 16-year-old female patient complained of fever, headache, purulent nasal discharge and severe muscle and joint pain. Additionally, she had polyuria and polydipsia. Investigations revealed a pituitary mass and panhypopituitarism. Positivity of c-ANCA and renal biopsy result compatible with WG confirmed the diagnosis.

[Pseudo-pituitary tumor and hypopituitarism secondary to a sphenoid sinus inverted papilloma]

Inverted papilloma (IP) is a benign uncommon epithelial tumor, arising mostly from the lateral nasal wall. Though benign, this lesion is highly invasive into surrounding tissues and malignant transformation may occur. Primary IP of the sphenoid sinus and intracranial extension with dural invasion, even without histological evidence of malignancy, has only rarely been described. Hypopituitarism as a complication of this lesion has never been reported. We describe the case of a 59-year-old woman who was evaluated because of a 5-year-history of severe headaches and abnormalities in the visual field. Magnetic resonance imaging (MRI) showed a 1.4 per 2.0 cm heterogeneous sellar lesion with suprasellar and sphenoid sinus extension, eroding the sellar floor with optic chiasm compression. Otolaryngologists gave her 16 mg/day of prednisone during approximately 3 months with a near total regression of the mass on MRI. The endocrine biochemical evaluation showed pituitary gonadal, thyroid and adrenal insufficiency. A new MRI showed growth of the tumor with obliteration of the sphenoid sinus. An endoscopic sinus biopsy revealed an IP, so a transnasal endoscopic sinus surgery was performed with complete resection evidenced by MRI a year later.

Ovarian tumor-derived ectopic hyperprolactinemia

To describe extreme hyperprolactinemia originating from a pituitary adenoma in the wall of an ovarian dermoid. This is a description of an unusual case and a review of ectopic prolactin production. Ectopic production of prolactin is a rare condition that has been reported in isolated organ system pathology including ovaries. An ovarian dermoid is a benign neoplasm that has the potential for active unregulated endocrine function. Hyperprolactinemia can result from functioning lactotrophs found in ovarian dermoids and can lead to clinical sequelae. Definitive treatment of the condition requires surgical removal of the functioning endocrine tissue. Extreme hyperprolactinemia caused by a pituitary tumor located within a dermoid has not been reported before. We present a case of profound hyperprolactinemia originating from a pituitary adenoma found in the wall of an ovarian dermoid and give a broad overview of the condition and literature. Ectopic prolactin production should always be considered in symptomatic patients found to have elevated serum levels and no findings on brain imaging.

What causes a prolactinoma to be aggressive or to become a pituitary carcinoma?

INTRODUCTION

Malignant prolactinoma is an exceedingly rare endocrine tumor and cannot be diagnosed on histological grounds alone. Similarly to other neuroendocrine tumors such as pheochromocytoma, the mitoses index, Ki-67, p53, and others are utilized in helping understand whether a tumor is benign or malignant or to better predict tumor behavior. We here present the unusual case of an unfortunate young man with an aggressive prolactinoma, the complications of which led to his premature death.

CASE REPORT

A 25-year-old white man developed severe headaches, low energy, and decreased libido. A brain magnetic resonance imaging (MRI) showed a 4 x 3 x 2 cm pituitary tumor invading the left cavernous sinus. Laboratory findings revealed elevated prolactin (470 ng/mL) and adrenocorticotropic hormone (ACTH, 82 pg/ml) and decreased total testosterone (176 ng/dl). Visual fields showed superior quadrantanopia in the left eye. Transsphenoidal pituitary resection was undertaken. Pathology revealed a prolactinoma with atypical cells, diffuse p53 nuclear labeling, and a Ki-67 index of 23% (high). Postoperatively, prolactin remained elevated (725-891 ng/ml) and cabergoline was increased to 1 mg three times weekly, with serum prolactin further increasing to 3507 ng/ml five months postoperatively. Repeat MRI revealed extension of the tumor with optic chiasm compression and left orbit invasion. Because of acute left vision loss with ophthalmoplegia, an urgent left frontotemporal craniotomy and tumor resection were conducted. The Ki-67 index of the tumor was 24.8%, the mitotic figure immunostain phosphohistone-H3 positive. Sixty percent (60%) of tumor cells were positive for p53. Cabergoline was increased to 1 mg daily but prolactin remained elevated (770 ng/ml). The patient then underwent proton beam radiation to the area of concern involving the sella. Prolactin thereafter improved to 44 ng/ml. He then developed acute vision loss of the right eye with an MRI showing tumor in the right cavernous sinus. A 15 mm dural-based right temporal mass believed to be a metastasis was also noted. Following this scan, he was considered too high risk for debulking surgery and instead underwent gamma knife irradiation to the sella area. This shrank the right cavernous sinus tumor mass, while the right temporal mass increased in size. The patient developed blindness and left-sided weakness and required enteral feeding and tracheostomy after prolonged intubation. A trial of chemotherapy with temozolomide (350 mg daily for 5 days) near the end of his life was unsuccessful. He died on home hospice 31 months after his first surgery.

CONCLUSION

Headaches, vision changes, and symptoms of androgen deficiency syndrome can be manifestations of an aggressive prolactinoma that might require surgery and additional medical therapy including cabergoline and temozolomide with an unpredictable time of survival.

Can cardiac surgery cause hypopituitarism?

Apoplexy of pituitary adenomas with subsequent hypopituitarism is a rare but well recognized complication following cardiac surgery. The nature of cardiac on-pump surgery provides a risk of damage to the pituitary because the vascular supply of the pituitary is not included in the cerebral autoregulation. Thus, pituitary tissue may exhibit an increased susceptibility to hypoperfusion, ischemia or intraoperative embolism. After on-pump procedures, patients often present with physical and psychosocial impairments which resemble symptoms of hypopituitarism. Therefore, we analyzed whether on-pump cardiac surgery may cause pituitary dysfunction also in the absence of pre-existing pituitary disease. Twenty-five patients were examined 3-12 months after on-pump cardiac surgery. Basal hormone levels for all four anterior pituitary hormone axes were measured and a short synacthen test and a growth hormone releasing hormone plus arginine (GHRH-ARG)-test were performed. Quality of life (QoL), depression, subjective distress for a specific life event, sleep quality and fatigue were assessed by means of self-rating questionnaires. Hormonal alterations were only slight and no signs of anterior hypopituitarism were found except for an insufficient growth hormone rise in two overweight patients in the GHRH-ARG-test. Psychosocial impairment was pronounced, including symptoms of moderate to severe depression in 9, reduced mental QoL in 8, dysfunctional coping in 6 and pronounced sleep disturbances in 16 patients. Hormone levels did not correlate with psychosocial impairment. On-pump cardiac surgery did not cause relevant hypopituitarism in our sample of patients and does not serve to explain the psychosocial symptoms of these patients.

Heparanase is highly expressed and regulates proliferation in GH-secreting pituitary tumor cells

Pituitary tumorigenesis involves remodeling of the extracellular matrix (ECM). Heparanase, an endoglycosidase capable of degrading heparan sulfate, a major polysaccharide constituent of the ECM, is implicated in diverse processes associated with ECM remodeling, such as morphogenesis, angiogenesis, and tumor invasion. The aim of this study was to investigate the possible role of heparanase in pituitary tumorigenesis. Human normal pituitaries and pituitary tumors were examined for heparanase mRNA and protein expression using real-time PCR and immunohistochemistry, respectively. Cell proliferation was assessed by colony formation after heparanase overexpression in GH3 and MtT/S cells. Cell viability and cell cycle progression were evaluated after heparanase gene silencing. Higher heparanase mRNA and protein expression was noted in GH tumors as compared with normal pituitaries. Heparanase overexpression in GH3 and MtT/S cells resulted in a 2- to 3-fold increase in colony number, compared with control cells. Cell viability decreased by 50% after heparanase gene silencing due to induced apoptosis reflected by increased fraction of cleaved poly-ADP-ribose polymerase and sub-G1 events. Notably, exogenously added heparanase enhanced epidermal growth factor receptor, Src, Akt, ERK, and p38 phosphorylation in pituitary tumor cells. Our results indicate that heparanase enhances pituitary cell viability and proliferation and may thus contribute to pituitary tumor development and progression.

The growth hormone-prolactin relationship: a neglected issue

During embryogenesis, the growth hormone-secreting cells (somatotrophs) and the prolactin-secreting cells (lactotrophs) develop from a common progenitor cell (somatomammotroph). Postnatally, in situations when one of these two hormones is oversecreted, often the second hormone is, too. The question posed is whether the increased secretion of growth hormone together with that of prolactin over long periods of time is a risk factor for malignancy.

Inactivation of PITX2 transcription factor induced apoptosis of gonadotroph tumoral cells

Nonfunctioning pituitary adenomas (NFPA; gonadotroph derived), even not inducing hormonal hypersecretion, cause significant morbidity by compression neighboring structures. No effective and specific medical methods are available so far for treating these tumors. The pituitary homeobox 2 (PITX2) gene is a member of the bicoid-like homeobox transcription factor family, which is involved in the Wnt/Dvl/β-catenin pathway. PITX2 is overexpressed in NFPA. PITX2 mutations are known to be responsible for Axenfield Rieger syndrome, a genetic disorder in which pituitary abnormalities have been detected. The R91P mutant identified in Axenfeld Rieger syndrome is a dominant-negative factor, which is able to block the expression of several pituitary genes activated by PITX2. To better understand the role of Pitx2 on gonadotroph tumorigenesis and to explore new approach for inhibiting tumoral growth, the R91P mutant was transferred via a lentiviral vector in tumoral gonadotroph cells of two kinds: the αT3-1 cell line and human adenoma cells. R91P mutant and small interfering RNA directed against Pitx2 both decreased the viability of αT3-1 cells via an apoptotic mechanism involving the activation of executioner caspase. Similar effects of the R91P mutant were observed on human gonadotroph cells in primary culture. Therefore, Pitx2 overexpression may play an antiapoptotic role during NFPA tumorigenesis.

Increased Wingless (Wnt) signaling in pituitary progenitor/stem cells gives rise to pituitary tumors in mice and humans

Wingless (Wnt)/β-catenin signaling plays an essential role during normal development, is a critical regulator of stem cells, and has been associated with cancer in many tissues. Here we demonstrate that genetic expression of a degradation-resistant mutant form of β-catenin in early Rathke's pouch (RP) progenitors leads to pituitary hyperplasia and severe disruption of the pituitary-specific transcription factor 1-lineage differentiation resulting in extreme growth retardation and hypopituitarism. Mutant mice mostly die perinatally, but those that survive weaning develop lethal pituitary tumors, which closely resemble human adamantinomatous craniopharyngioma, an epithelial tumor associated with mutations in the human β-catenin gene. The tumorigenic effect of mutant β-catenin is observed only when expressed in undifferentiated RP progenitors, but tumors do not form when committed or differentiated cells are targeted to express this protein. Analysis of affected pituitaries indicates that expression of mutant β-catenin leads to a significant increase in the total numbers of pituitary progenitor/stem cells as well as in their proliferation potential. Our findings provide insights into the role of the Wnt pathway in normal pituitary development and demonstrate a causative role for mutated β-catenin in an undifferentiated RP progenitor in the genesis of murine and human craniopharyngioma.

[Impact of L-thyroxine replacement therapy on pituitary changes secondary to congenital primary hypothyroidism--three cases report]

The aim of the study was an evaluation of the impact of L-thyroxine substitution therapy on the size and structure of the pituitary gland using MRI in three patients with pituitary hyperplasia or tumor secondary to primary congenital hypothyroidism. Along with imaging studies (MRI, skull X-rays) all patients had performed hormonal tests. All hormones (except adrenocorticotropic hormone) of anterior pituitary lobe were measured in basal condition, and some of them (GH, PRL) after stimulation tests, which showed hyperprolactinemia in one case and pituitary somatotropin insufficiency in the other. Only in one out of three patients the regression of the pituitary enlargement was complete, whereas in second case the regression was partial and in third patient evaluation revealed no changes on the MRI. Correct L-thyroxine therapy prevents enlargement of pituitary gland and may regress these changes, but is not the only outcome of pituitary enlargement. Those results shows, that other coexisting disturbances like TSH-secreting adenoma or thyroid hormone resistance must be considered when the treatment is not successful.

Pathogenesis of pituitary tumors

Pituitary adenomas may hypersecrete hormones (including prolactin, growth hormone and adrenocorticotropic hormone, and rarely follicle-stimulating hormone, luteinizing hormone or TSH) or may be nonfunctional. Despite their high prevalence in the general population, these tumors are invariably benign and exhibit features of differentiated pituitary cell function as well as premature proliferative arrest. Pathogenesis of dysregulated pituitary cell proliferation and unrestrained hormone hypersecretion may be mediated by hypothalamic, intrapituitary and/or peripheral factors. Altered expression of pituitary cell cycle genes, activation of pituitary selective oncoproteins or loss of pituitary suppressor factors may be associated with aberrant growth factor signaling. Considerable information on the etiology of these tumors has been derived from transgenic animal models, which may not accurately and universally reflect human tumor pathophysiology. Understanding subcellular mechanisms that underlie pituitary tumorigenesis will enable development of tumor aggression markers as well as novel targeted therapies.

[Magnetic resonance imaging and hormonal profile of the pituitary gland in patients with primary congenital hypothyroidism]

The aim of our study was an estimation of the size and structure of the pituitary gland using MRI and the estimation of hormonal profile of the pituitary anterior lobe (except for ACTH) in 21 adult patients with congenital primary hypothyroidism.

MATERIAL AND METHODS

The studied group was divided into 2 subgroups: A--with normal level of serum TSH and B--with its elevated. The MRI showed pituitary hyperplasia or tumor in 28.5% of patients, partially empty sella in 14.3% and hypoplasia in 9.5%. In subgroup B there were mostly hyperplasia or tumor (35.7%), while in subgroup A there were no domination of any abnormalities.

RESULTS

Serum mean TSH level was 49.8+/-86.2 mU/l with an increase in 67%. The mean prolactin was 11.2+/-7.5 mg/ml with an increase in 19%. Serum LH and FSH concentrations were normal in the whole group. The mean alpha subunit level was elevated in 52%. In 42.8% somatotropic hypopituitarism was recognised due to GH stimulation tests.

CONCLUSIONS

The TRH hyperstimulation in patients with congenital primary hypothyroidism may lead to pituitary hyperplasia or tumor visible on MRI and to pituitary hormonal abnormalities.

Adult pituitary stem cells: from pituitary plasticity to adenoma development

The pituitary needs high plasticity of the hormone-producing cell compartment to generate the continuously changing hormonal signals that govern the key physiological processes it is involved in, as well as homeostatic cell turnover. However, the underlying mechanisms are still poorly understood. It was proposed that adult stem cells direct the generation of newborn cells with a hormonal phenotype according to the physiological requirements. However, only in recent years adult pituitary stem cells have begun to be phenotypically characterized in several studies that identified multiple stem/progenitor cell candidates. Also considering the incompletely defined features of this cell subpopulation, some discrepancies among the different reports are clearly apparent and long-term self-renewal remains to be unequivocally demonstrated. Here, all the recently published evidence is analyzed, trying, when possible, to reconcile the results of the different studies. Finally, with the perspective of shedding light on pituitary tumorigenesis and the development of potentially new pharmacological approaches directed against these cells, very recent evidence on the presence of putative cancer stem cells in human pituitary adenomas is discussed.

HMGA2: A pituitary tumour subtype-specific oncogene?

The high mobility group AT-hook (HMGA) proteins, a family of DNA architectural factors, are highly expressed during embryogenesis and play a crucial role in several different biological processes, as well as in tumorigenesis of a wide range of tissues, including pituitary. Indeed, HMGA2 has been found rearranged and amplified in human prolactinomas, and transgenic mice overexpressing either Hmga1 or Hmga2 develop pituitary adenomas secreting prolactin and growth hormone. Here, we overview HMGA proteins in human tumours, focusing on pituitary adenomas and the mechanisms by which the HMGA proteins are involved in their onset and development. Different HMGA-dependent potential drives of pituitary oncogenesis are discussed as future research directions in the field.

PRKAR1A and the evolution of pituitary tumors

Carney complex (CNC) is an inherited tumor predisposition associated with pituitary tumors, including GH-producing pituitary adenomas and rare reports of prolactinomas. This disease is caused by mutations in PRKAR1A, which encodes the type 1A regulatory subunit of the cAMP-dependent protein kinase, PKA. Loss of PRKAR1A causes enhanced PKA signaling, which leads to pituitary tumorigenesis. Mutations in the gene have not been detected in sporadic pituitary tumors, but there is some data to suggest that non-genomic mechanisms may cause loss of protein expression. Unlike CNC patients, mice heterozygous for Prkar1a mutations do not develop pituitary tumors, although complete knockout of the gene in the Pit1 lineage of the pituitary produces GH-secreting pituitary adenomas. These data indicate that complete loss of Prkar1a/PRKAR1A is able to cause pituitary tumors in mice and men. The pattern of tumors is likely related to the signaling pathways employed in specific pituitary cell types.

Pituitary tumors: cell type-specific roles for BMP-4

BMP-4 plays a crucial role not only in the formation of the anterior pituitary during embryo development but also in the pathogenesis of pituitary tumors in adults. In tumor cells, BMP-4 promotes prolactin secretion and lactotroph cell proliferation through a Smad-estrogen receptor crosstalk but it inhibits ACTH production and cell proliferation of corticotrophs. In addition, BMP-4 increases GH secretion in rat pituitary tumor somatolactotroph GH3 cells and FSHbeta subunit gene transcription in the murine gonadotroph cell line, LbetaT2. Therefore, BMP-4 has a differential role on different types of pituitary tumors: it promotes pituitary prolactinoma while it inhibits corticotroph pathogenesis in Cushing's disease. The modulation of BMP-4 also plays an important role in the therapeutic mechanism of action of bromocriptine, somatostatin analogs and retinoic acid.

Cyclins and their related proteins in pituitary tumourigenesis

Pituitary tumours are benign neoplasms that may cause major endocrine dysfunction. Transgenic disruption of the cell cycle machinery frequently leads to pituitary adenoma formation in animal models. The molecular analysis of human pituitary tumours has found various alterations in the expression of cell cycle regulators: cyclins, cyclin-dependent kinases and their inhibitors. There are also different mechanisms (e.g. hypermethylation, frameshift mutations, increased proteasome degradation) responsible for changed expression in cyclin mRNA and protein. It is probable that the primary initiating events lie beyond the cell cycle and may be related to co-activation of Akt, MAP-kinase and beta-catenin pathways. Nevertheless, molecular CDK inhibitors may play a role in pituitary tumour treatment in the future.

Enhanced LH action in transgenic female mice expressing hCGbeta-subunit induces pituitary prolactinomas; the role of high progesterone levels

The etiology of pituitary adenomas remains largely unknown, with the exception of involvement of estrogens in the formation of prolactinomas. We have examined the molecular pathogenesis of prolactin-producing pituitary adenomas in transgenic female mice expressing the human choriongonadotropin (hCG) beta-subunit. The LH/CG bioactivity is elevated in the mice, with consequent highly stimulated ovarian progesterone (P(4)) production, in the face of normal estrogen secretion. Curiously, despite normal estrogen levels, large prolactinomas developed in these mice, and we provide here several lines of evidence that the elevated P(4) levels are involved in the growth of these estrogen-dependent tumors. The antiprogestin mifepristone inhibited tumor growth, and combined postgonadectomy estradiol/P(4) treatment was more effective than estrogen alone in inducing tumor growth. Evidence for direct growth-promoting effect of P(4) was obtained from cultures of primary mouse pituitary cells and rat somatomammotroph GH3 cells. The mouse tumors and cultured cells revealed stimulation of the cyclin D1/cyclin-dependent kinase 4/retinoblastoma protein/transcription factor E2F1 pathway in the growth response to P(4). If extrapolated to humans, and given the importance of endogenous P(4) and synthetic progestins in female reproductive functions and their pharmacotherapy, it is relevant to revisit the potential role of these hormones in the origin and growth of prolactinomas.

Cytokines and genes in pituitary tumorigenesis: RSUME role in cell biology

Cytokines of the IL-6 or gp130 family regulate many cellular responses and play regulatory roles in numerous tissues, and are placed as auto-paracrine regulators of pituitary function acting in normal and tumoral anterior pituitary cells. Especially, IL-6 has a regulatory role in the hormone secretion and growth of the anterior pituitary and is involved in adenoma pathogenesis. Recently, IL-6 has been shown to mediate oncogene-induced senescence (OIS). IL-6 might participate in such a process in adenomas pituitary as well. From pituitary tumoral gp130 overexpressing cells, an unknown protein, RSUME, has been cloned. RSUME is induced by hypoxia in pituitary tumors and regulate pathways involved in angiogenic and tumorigenic processes (NF-kappaB/IkappaB and HIF-1alpha pathways). Thus, it could have an important role in the development of the pituitary tumors.

Pituitary carcinomas

Pituitary carcinoma is a extremely rare and is characterized by a very poor prognosis. Even if at diagnosis the presence of metastases is required to define a pituitary carcinoma, the lesion was almost invariably diagnosed first as a benign pituitary tumor, that after a variable period of latency, ranging from few months to many years, changed its natural course to an aggressive pituitary tumor poorly responsive to therapy. Recent studies have partially clarified its molecular pathogenesis and found possible markers of aggressiveness in order to make an earlier diagnosis, when still treatment could improve their prognosis. Most pituitary carcinomas are functioning, and ACTH- and PRL-secreting carcinomas are the most frequent. Treatment includes surgery, radiotherapy, medical therapy and chemotherapy, but the poor results with current therapies should prompt all investigators to better understand its pathogenesis and searching new molecular targets for treatments.

Panhypopituitarism apparently caused by hypophysitis masking a rapid development of a craniopharyngioma. A case report

We report the case of a 39-year-old male presenting with panhypopituitarism and diabetes insipidus. MR imaging showed focal thickening of the pituitary infundibulum and infiltration of the anterior pituitary lobe, suggesting hypophysitis. Hormonal replacement therapy induced a pronounced amelioration of general well-being. Eight months later the subject developed visual disturbances. MR imaging now showed a cystic sellar mass. Surgical drainage was performed. A second operation was necessary six weeks Later because of recurrent visual field defects. Diagnosis of papillary craniopharyngioma was finally made. This case demonstrates the remarkably rapid development of a craniopharyngioma, which initial radiological appearance was suggestive of hypophysitis. It also emphasizes the need of repeat MR examination in case of unusual presentation of hypopituitarism.

Multiple endocrine neoplasia type 1 knockout mice develop parathyroid, pancreatic, pituitary and adrenal tumours with hypercalcaemia, hypophosphataemia and hypercorticosteronaemia

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized in man by parathyroid, pancreatic, pituitary and adrenal tumours. The MEN1 gene encodes a 610-amino acid protein (menin) which is a tumour suppressor. To investigate the in vivo role of menin, we developed a mouse model, by deleting Men1 exons 1 and 2 and investigated this for MEN1-associated tumours and serum abnormalities. Men1(+/-) mice were viable and fertile, and 220 Men1(+/-) and 94 Men1(+/+) mice were studied between the ages of 3 and 21 months. Survival in Men1(+/-) mice was significantly lower than in Men1(+/+) mice (<68% vs >85%, P<0.01). Men1(+/-) mice developed, by 9 months of age, parathyroid hyperplasia, pancreatic tumours which were mostly insulinomas, by 12 months of age, pituitary tumours which were mostly prolactinomas, and by 15 months parathyroid adenomas and adrenal cortical tumours. Loss of heterozygosity and menin expression was demonstrated in the tumours, consistent with a tumour suppressor role for the Men1 gene. Men1(+/-) mice with parathyroid neoplasms were hypercalcaemic and hypophosphataemic, with inappropriately normal serum parathyroid hormone concentrations. Pancreatic and pituitary tumours expressed chromogranin A (CgA), somatostatin receptor type 2 and vascular endothelial growth factor-A. Serum CgA concentrations in Men1(+/-) mice were not elevated. Adrenocortical tumours, which immunostained for 3-beta-hydroxysteroid dehydrogenase, developed in seven Men1(+/-) mice, but resulted in hypercorticosteronaemia in one out of the four mice that were investigated. Thus, these Men1(+/-) mice are representative of MEN1 in man, and will help in investigating molecular mechanisms and treatments for endocrine tumours.