Pituitary pathology in patients with Carney Complex: growth-hormone producing hyperplasia or tumors and their association with other abnormalities

The Spectrum of GH Excess in Carney Complex and Genotype-phenotype Correlations

CONTEXT

Carney complex (CNC) is a familial neoplasia syndrome associated with GH excess (GHE).

OBJECTIVE

To describe the frequency of GHE in a large cohort of patients with CNC and to identify genotype-phenotype correlations.

METHODS

Patients with CNC with at least 1 biochemical evaluation of GH secretion at our center from 1995 to 2021 (n = 140) were included in the study. Diagnosis of GHE was based on levels of IGF-1, GH suppression during oral glucose tolerance test, GH stimulation after thyrotropin administration and overnight GH secretion.

RESULTS

Fifty patients (35.7%) had GHE, and 28 subjects (20%) had symptomatic acromegaly, with median age at diagnosis of 25.3 and 26.1 years, respectively. Most of the patients (99.3%) had a PRKAR1A gene defect. There was a higher risk of GHE in patients harboring a variant that led to no expression of the affected allele [hazard risk (HR): 3.06, 95% confidence interval (CI): 1.2-7.8] and for patients harboring the hotspot variant c.491_492delTG (HR: 2.10, 95% CI: 1.1-4.1). Almost half of patients with CNC had an abnormal finding on pituitary imaging. CNC patients with abnormal pituitary imaging had a higher risk of GHE (HR: 2.94, 95% CI: 1.5-5.8), especially when single or multiple adenoma-like lesions were identified. Management of patients with symptomatic acromegaly involved surgical and medical approaches.

CONCLUSION

Dysregulation of GH secretion is a common finding in CNC. Knowing the clinical spectrum of this disorder and its association with genetic and imaging characteristics of the patient make more likely its prompt diagnosis and better management.

From cortisol-producing adrenal adenoma to atrial myxoma, through nivolumab-induced hypophysitis: a complicated case report of Carney Complex

PURPOSE

Carney complex (CNC) is a rare, autosomal dominant syndrome, most commonly caused by PRKAR1A gene mutations and characterized by pigmented skin and mucosal changes with multiple endocrine and non-endocrine tumours. This case report highlights the diagnostic challenges associated with CNC in a patient with multiple neoplasms and a complex medical history, including cortisol-producing adrenal adenoma, breast cancer, melanoma, and atrial myxoma.

METHODS

We report the case of a 41-year-old woman with a medical history of left adrenalectomy for cortisol producing adenoma (2005) with no sign of adrenal insufficiency at follow-up, right mastectomy for BRCA1/2 negative carcinoma (2013) and left parotid BRAF-V600E wild-type melanoma (2019), treated with nivolumab adjuvant therapy. In August 2019, following the fifth nivolumab administration, the patient developed central hypocortisolism due to iatrogenic hypophysitis, confirmed by brain MRI and properly treated with oral hydrocortisone. Nivolumab was discontinued due to the patient's decision. In October 2020 and April 2021, the patient had ischaemic strokes, requiring systemic thrombolysis. Echocardiographic examination then revealed a left atrial mass, with histological finding of myxoma.

RESULTS

Given the rarity of this neoplasm and the suspicion of a syndromic disorder, a genetic evaluation was conducted, which confirmed a PRKAR1A gene mutation and the diagnosis of Carney complex.

CONCLUSION

This case illustrates the diagnostic challenges in CNC, especially in patients with multiple tumourous manifestations and a wide spectrum of life-threatening clinical presentations. It underscores the importance of a multidisciplinary approach to diagnose and manage rare diseases, improving patient outcomes through timely genetic testing and coordinated care.

The Spectrum of Familial Pituitary Neuroendocrine Tumors

Hereditary pituitary tumorigenesis is seen in a relatively small proportion (around 5%) of patients with pituitary neuroendocrine tumors (PitNETs). The aim of the current review is to describe the main clinical and molecular features of such pituitary tumors associated with hereditary or familial characteristics, many of which have now been genetically identified. The genetic patterns of inheritance are classified into isolated familial PitNETs and the syndromic tumors. In general, the established genetic causes of familial tumorigenesis tend to present at a younger age, often pursue a more aggressive course, and are more frequently associated with growth hormone hypersecretion compared to sporadic tumors. The mostly studied molecular pathways implicated are the protein kinase A and phosphatidyl-inositol pathways, which are in the main related to mutations in the syndromes of familial isolated pituitary adenoma (FIPA), Carney complex syndrome, and X-linked acrogigantism. Another well-documented mechanism consists of the regulation of p27 or p21 proteins, with further acceleration of the pituitary cell cycle through the check points G1/S and M/G1, mostly documented in multiple endocrine neoplasia type 4. In conclusion, PitNETs may occur in relation to well-established familial germline mutations which may determine the clinical phenotype and the response to treatment, and may require family screening.

Neurofibromatosis Type 1 Has a Wide Spectrum of Growth Hormone Excess

Overgrowth due to growth hormone (GH) excess affects approximately 10% of patients with neurofibromatosis type 1 (NF1) and optic pathway glioma (OPG). Our aim is to describe the clinical, biochemical, pathological, and genetic features of GH excess in a retrospective case series of 10 children and adults with NF1 referred to a tertiary care clinical research center. Six children (median age = 4 years, range of 3−5 years), one 14-year-old adolescent, and three adults (median age = 42 years, range of 29−52 years) were diagnosed with NF1 and GH excess. GH excess was confirmed by the failure to suppress GH (<1 ng/mL) on oral glucose tolerance test (OGTT, n = 9) and frequent overnight sampling of GH levels (n = 6). Genetic testing was ascertained through targeted or whole-exome sequencing (n = 9). Five patients (all children) had an OPG without any pituitary abnormality, three patients (one adolescent and two adults) had a pituitary lesion (two tumors, one suggestive hyperplasia) without an OPG, and two patients (one child and one adult) had a pituitary lesion (a pituitary tumor and suggestive hyperplasia, respectively) with a concomitant OPG. The serial overnight sampling of GH levels in six patients revealed abnormal overnight GH profiling. Two adult patients had a voluminous pituitary gland on pituitary imaging. One pituitary tumor from an adolescent patient who harbored a germline heterozygous p.Gln514Pro NF1 variant stained positive for GH and prolactin. One child who harbored a heterozygous truncating variant in exon 46 of NF1 had an OPG that, when compared to normal optic nerves, stained strongly for GPR101, an orphan G protein-coupled receptor causing GH excess in X-linked acrogigantism. We describe a series of patients with GH excess and NF1. Our findings show the variability in patterns of serial overnight GH secretion, somatotroph tumor or hyperplasia in some cases of NF1 and GH excess. Further studies are required to ascertain the link between NF1, GH excess and GPR101, which may aid in the characterization of the molecular underpinning of GH excess in NF1.

The cAMP-signaling cancers: Clinically-divergent disorders with a common central pathway

The cAMP-signaling cancers, which are defined by functionally-significant somatic mutations in one or more elements of the cAMP signaling pathway, have an unexpectedly wide range of cell origins, clinical manifestations, and potential therapeutic options. Mutations in at least 9 cAMP signaling pathway genes (TSHR, GPR101, GNAS, PDE8B, PDE11A, PRKARA1, PRKACA, PRKACB, and CREB) have been identified as driver mutations in human cancer. Although all cAMP-signaling pathway cancers are driven by mutation(s) that impinge on a single signaling pathway, the ultimate tumor phenotype reflects interactions between five critical variables: (1) the precise gene(s) that undergo mutation in each specific tumor type; (2) the effects of specific allele(s) in any given gene; (3) mutations in modifier genes (mutational "context"); (4) the tissue-specific expression of various cAMP signaling pathway elements in the tumor stem cell; and (5) and the precise biochemical regulation of the pathway components in tumor cells. These varying oncogenic mechanisms reveal novel and important targets for drug discovery. There is considerable diversity in the "druggability" of cAMP-signaling components, with some elements (GPCRs, cAMP-specific phosphodiesterases and kinases) appearing to be prime drug candidates, while other elements (transcription factors, protein-protein interactions) are currently refractory to robust drug-development efforts. Further refinement of the precise driver mutations in individual tumors will be essential for directing priorities in drug discovery efforts that target these mutations.

A novel mutation in PRKAR1A gene in a patient with Carney complex presenting with pituitary macroadenoma, acromegaly, Cushing's syndrome and recurrent atrial myxoma

Carney complex (CNC) is a rare syndrome of multiple endocrine and non-endocrine tumors. In this paper we present a 23-year-old Iranian woman with CNC who harbored a novel mutation (c.642dupT) in PRKAR1A gene. This patient presented with pituitary macroadenoma, acromegaly, recurrent atrial myxoma, Cushing's syndrome secondary to primary pigmented nodular adrenocortical disease and pigmented schwanoma of the skin. PRKAR1A gene was PCR amplified using genomic DNA and analyzed for sequence variants which revealed the novel mutation resulting in substitution of amino acid cysteine instead of the naturally occurring valine in the peptide chain and a premature stop codon at position 18 (V215CfsX18). This change leads to development of tumors in different organs due to lack of tumor suppressive activity secondary to failure of synthesis of the related protein.

Frequency and Incidence of Carney Complex Manifestations: A Prospective Multicenter Study With a Three-Year Follow-Up

INTRODUCTION

Carney Complex (CNC) is a rare multiple endocrine and nonendocrine neoplasia syndrome. Manifestations and genotype-phenotype correlations have been described by retrospective studies, but no prospective study evaluating the occurrence of the different manifestations has been available so far.

METHODS

This multicenter national prospective study included patients with CNC, primary pigmented nodular adrenal disease (PPNAD), or a pathogenic PRKAR1A mutation; after a full initial workup, participants were followed for 3 years with annual standardized evaluation.

RESULTS

The cohort included 70 patients (50 female/20 male, mean age 35.4 ± 16.7 years, 81% carrying PRKAR1A mutation). The initial investigations allowed identification of several manifestations. At the end of the 3-year follow-up, the newly diagnosed manifestations of the disease were subclinical acromegaly in 6 patients, bilateral testicular calcifications in 1 patient, and cardiac myxomas in 2 patients. Recurrences of cardiac myxomas were diagnosed in 4 patients during the 3-year follow-up study period. Asymptomatic abnormalities of the corticotroph and somatotroph axis that did not meet criteria of PPNAD and acromegaly were observed in 11.4% and 30% of the patients, respectively. Patients carrying the PRKAR1A c.709-7del6 mutation had a mild phenotype.

CONCLUSION

This study underlines the importance of a systematic follow-up of the CNC manifestations, especially a biannual screening for cardiac myxoma. By contrast, regular screening for the other manifestations after a first extensive workup could be spread out, leading to a lighter and more acceptable follow-up schedule for patients. These are important results for recommendations for long-term management of CNC patients.

The Genetics of Pituitary Adenomas

The genetic landscape of pituitary adenomas (PAs) is diverse and many of the identified cases remain of unclear pathogenetic mechanism. Germline genetic defects account for a small percentage of all patients and may present in the context of relevant family history. Defects in AIP (mutated in Familial Isolated Pituitary Adenoma syndrome or FIPA), MEN1 (coding for menin, mutated in Multiple Endocrine Neoplasia type 1 or MEN 1), PRKAR1A (mutated in Carney complex), GPR101 (involved in X-Linked Acrogigantism or X-LAG), and SDHx (mutated in the so called "3 P association" of PAs with pheochromocytomas and paragangliomas or 3PAs) account for the most common familial syndromes associated with PAs. Tumor genetic defects in USP8, GNAS, USP48 and BRAF are some of the commonly encountered tissue-specific changes and may explain a larger percentage of the developed tumors. Somatic (at the tumor level) genomic changes, copy number variations (CNVs), epigenetic modifications, and differential expression of miRNAs, add to the variable genetic background of PAs.

Acromegaly in Carney complex

PURPOSE

Carney complex (CNC) is a rare autosomal dominant syndrome, characterized by mucocutaneous pigmentation, cardiac, cutaneous myxomas and endocrine overactivity. It is generally caused by inactivating mutations in the PRKAR1A (protein kinase cAMP-dependent type I regulatory subunit alpha) gene. Acromegaly is an infrequent manifestation of CNC, reportedly diagnosed in 10% of patients.

METHODS

We here report the case of a patient who was concomitantly diagnosed with Carney complex, due to a new mutation in PRKAR1A ((NM_002734.3:c.80_83del, p.(Ile27Lysfs*101 in exon 2), and acromegaly. In parallel, we conducted an extensive review of published case reports of acromegaly in the setting of CNC.

RESULTS

The 43-year-old patient was diagnosed with an acromegaly due to a GH-secreting pituitary microadenoma resistant to somatostatin analogs. He underwent transsphenoidal surgery in our tertiary referral center, which found a pure GH-secreting adenoma. In the literature, we identified 57 cases (24 men, 33 women) of acromegaly in CNC patients. The median age at diagnosis was 28.8 ± 12 year and there were 6 cases of gigantism. Acromegaly revealed CNC in only 4 patients. 24 patients had a microadenoma and two carried pituitary hyperplasia and/or multiple adenomas, suggesting that CNC may result in a higher proportion of microadenoma as compared to non-CNC acromegaly.

CONCLUSIONS

Although it rarely reveals CNC, acromegaly is diagnosed at a younger age in this setting, with a higher proportion of microadenomas.

Germline USP8 Mutation Associated With Pediatric Cushing Disease and Other Clinical Features: A New Syndrome

BACKGROUND

Somatic mutations in the ubiquitin-specific peptidase 8 (USP8) gene are common in corticotropinomas of children with Cushing disease (CD). We report a unique patient with a germline USP8 mutation who presented with CD and a constellation of other findings that constitute an intriguing genetic syndrome.

CASE DESCRIPTION

We describe a 16-year-old female with CD, developmental delay, dysmorphic features, ichthyosiform hyperkeratosis, chronic lung disease, chronic kidney disease, hyperglycemia, dilated cardiomyopathy with congestive heart failure, and previous history of hyperinsulinism and partial GH deficiency. She was diagnosed with CD at 14 years old and underwent transsphenoidal surgery. Despite initial improvement, she developed recurrent CD.

METHODS

DNA was extracted from peripheral blood and tumor DNA; whole-exome and Sanger confirmatory sequencing were performed. Immunohistochemistry was performed on the resected adenoma.

RESULTS

A de novo germline heterozygous USP8 mutation (c.2155T>C, p.S719P) in the critical 14-3-3 binding motif hot spot locus of the gene was identified in both the peripheral blood and tumor DNA. Histopathologic evaluation of the resected tumor confirmed an ACTH-secreting adenoma.

CONCLUSION

Somatic USP8 mutations are common in adenomas causing CD, but to date, no germline defects have been reported. We describe a patient with a de novo germline USP8 mutation with recurrent CD and multiple other medical problems. This unique patient informs us of the multitude of signaling events that may be controlled by USP8.

Molecular determinants of the response to medical treatment of growth hormone secreting pituitary neuroendocrine tumors

Acromegaly is a chronic systemic disease mainly caused by a growth hormone (GH)-secreting pituitary neuroendocrine tumor (PitNETs), which is associated with many health complications and increased mortality when not adequately treated. Transsphenoidal surgery is considered the treatment of choice in GH-secreting PitNETs, but patients in whom surgery cannot be considered or with persistent disease after surgery require medical therapy. Treatment with available synthetic somatostatin analogues (SSAs) is considered the mainstay in the medical management of acromegaly which exert their beneficial effects through the binding to a family of G-protein coupled receptors encoded by 5 genes (SSTR1-5). However, although it has been demonstrated that the SST1-5 receptors are physically present in tumor cells, SSAs are in many cases ineffective (i.e. approximately 10-30% of patients with GH-secreting PitNET are unresponsive to SSAs), suggesting that other cellular/molecular determinants could be essential for the response to the pharmacological treatment in patients with GH-secreting PitNETs. Therefore, the scrutiny of these determinants might be used for the identification of subgroups of patients in whom an appropriate pharmacological treatment can be successfully employed (responders vs. non-responders). In this review, we will describe some of the existing, classical and novel, genetic and molecular determinants involved in the response of patients with GH-secreting PitNETs to the available therapeutic treatments, as well as new molecular/therapeutic approaches that could be potentially useful for the treatment of GH-secreting PitNETs.

The causes and consequences of pituitary gigantism

In the general population, height is determined by a complex interplay between genetic and environmental factors. Pituitary gigantism is a rare but very important subgroup of patients with excessive height, as it has an identifiable and clinically treatable cause. The disease is caused by chronic growth hormone and insulin-like growth factor 1 secretion from a pituitary somatotrope adenoma that forms before the closure of the epiphyses. If not controlled effectively, this hormonal hypersecretion could lead to extremely elevated final adult height. The past 10 years have seen marked advances in the understanding of pituitary gigantism, including the identification of genetic causes in ~50% of cases, such as mutations in the AIP gene or chromosome Xq26.3 duplications in X-linked acrogigantism syndrome. Pituitary gigantism has a male preponderance, and patients usually have large pituitary adenomas. The large tumour size, together with the young age of patients and frequent resistance to medical therapy, makes the management of pituitary gigantism complex. Early diagnosis and rapid referral for effective therapy appear to improve outcomes in patients with pituitary gigantism; therefore, a high level of clinical suspicion and efficient use of diagnostic resources is key to controlling overgrowth and preventing patients from reaching very elevated final adult heights.

Pediatric Pituitary Adenoma: Case Series, Review of the Literature, and a Skull Base Treatment Paradigm

Background  Pediatric pituitary adenoma is a rare skull base neoplasm, accounting for 3% of all intracranial neoplasms in children and 5% of pituitary adenomas. Compared with pituitary tumors in adults, secreting tumors predominate and longer disease trajectories are expected due to the patient age resulting in a natural history and treatment paradigm that is complex and controversial. Objectives  The aims of this study were to describe a large, single-institution series of pediatric pituitary adenomas with extensive long-term follow-up and to conduct a systematic review examining outcomes after pituitary adenoma surgery in the pediatric population. Methods  The study cohort was compiled by searching institutional pathology and operative reports using diagnosis and site codes for pituitary and sellar pathology, from 1956 to 2016. Systematic review of the English language literature since 1970 was conducted using PubMed, MEDLINE, Embase, and Google Scholar. Results  Thirty-nine surgically managed pediatric pituitary adenomas were identified, including 15 prolactinomas, 14 corticotrophs, 7 somatotrophs, and 4 non-secreting adenomas. All patients underwent transsphenoidal resection (TSR) as the initial surgical treatment. Surgical cure was achieved in 18 (46%); 21 experienced recurrent/persistent disease, with secondary treatments including repeat surgery in 10, radiation in 14, adjuvant pharmacotherapy in 11, and bilateral adrenalectomy in 3. At the last follow-up (median 87 months, range 3-581), nine remained with recurrent/persistent disease (23%). Thirty-seven publications reporting surgical series of pediatric pituitary adenomas were included, containing 1,284 patients. Adrenocorticotropic hormone (ACTH)-secreting tumors were most prevalent (43%), followed by prolactin (PRL)-secreting (37%), growth hormone (GH)-secreting (12%), and nonsecreting (7%). Surgical cure was reported in 65%. Complications included pituitary insufficiency (23%), permanent visual dysfunction (6%), chronic diabetes insipidus (DI) (3%), and postoperative cerebrospinal fluid (CSF) leak (4%). Mean follow-up was 63 months (range 0-240), with recurrent/persistent disease reported in 18% at the time of last follow-up. Conclusion  Pediatric pituitary adenomas are diverse and challenging tumors with complexities far beyond those encountered in the management of routine adult pituitary disease, including nuanced decision-making, a technically demanding operative environment, high propensity for recurrence, and the potentially serious consequences of hypopituitarism with respect to fertility and growth potential in a pediatric population. Optimal treatment requires a high degree of individualization, and patients are most likely to benefit from consolidated, multidisciplinary care in highly experienced centers.

Emergence of Pituitary Adenoma in a Child during Surveillance: Clinical Challenges and the Family Members' View in an AIP Mutation-Positive Family

INTRODUCTION

Germline aryl hydrocarbon receptor-interacting protein (AIP) mutations are responsible for 15-30% of familial isolated pituitary adenomas (FIPAs). We report a FIPA kindred with a heterozygous deletion in AIP, aiming to highlight the indications and benefits of genetic screening, variability in clinical presentations, and management challenges in this setting.

PATIENTS

An 18-year-old male was diagnosed with a clinically nonfunctioning pituitary adenoma (NFPA). Two years later, his brother was diagnosed with a somatolactotrophinoma, and a small Rathke's cleft cyst and a microadenoma were detected on screening in their 17-year-old sister. Following amenorrhoea, their maternal cousin was diagnosed with hyperprolactinaemia and two distinct pituitary microadenomas. A 12-year-old niece developed headache and her MRI showed a microadenoma, not seen on a pituitary MRI scan 3 years earlier.

DISCUSSION

Out of the 14 members harbouring germline AIP mutations in this kindred, 5 have pituitary adenoma. Affected members had different features and courses of disease. Bulky pituitary and not fully suppressed GH on OGTT can be challenging in the evaluation of females in teenage years. Multiple pituitary adenomas with different secretory profiles may arise in the pituitary of these patients. Small, stable NFPAs can be present in mutation carriers, similar to incidentalomas in the general population. Genetic screening and baseline review, with follow-up of younger subjects, are recommended in AIP mutation-positive families.

Carney complex review: Genetic features

Carney complex is a multiple neoplasia syndrome having endocrine and non-endocrine manifestations. Diagnostic criteria include myxoma, lentigines, and primary pigmented nodular adrenocortical disease, amongst other signs/symptoms. In most cases it is an autosomal dominant disease, and diagnosis therefore requires study and follow-up of the family members. Inactivating mutations of the PRKAR1A gene were identified as the main cause of the disease, although since 2015 other disease-related genes, including PRKACA and PRKACB activating mutations, have also been related with Carney complex. This review will address the genetic aspects related to Carney complex.

PRKAR1A mutation causing pituitary-dependent Cushing disease in a patient with Carney complex

CONTEXT

Carney complex (CNC) is an autosomal dominant condition caused, in most cases, by an inactivating mutation of the PRKAR1A gene, which encodes for the type 1 alpha regulatory subunit of protein kinase A. CNC is characterized by the occurrence of endocrine overactivity, myxomas and typical skin manifestations. Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD) is the most frequent endocrine disease observed in CNC.

CASE DESCRIPTION

Here, we describe the first case of a patient with CNC and adrenocorticotropic hormone (ACTH)-dependent Cushing disease due to a pituitary corticotroph adenoma. Loss-of-heterozygosity analysis of the pituitary tumour revealed loss of the wild-type copy of PRKAR1A, suggesting a role of this gene in the pituitary adenoma development.

CONCLUSION

PRKAR1A loss-of-function mutations can rarely lead to ACTH-secreting pituitary adenomas in CNC patients. Pituitary-dependent disease should be considered in the differential diagnosis of Cushing syndrome in CNC patients.

Genetic Aspects of Pituitary Adenomas

Although most of pituitary adenomas are benign, they may cause significant burden to patients. Sporadic adenomas represent the vast majority of the cases, where recognized somatic mutations (eg, GNAS or USP8), as well as altered gene-expression profile often affecting cell cycle proteins have been identified. More rarely, germline mutations predisposing to pituitary adenomas -as part of a syndrome (eg, MEN1 or Carney complex), or isolated to the pituitary (AIP or GPR101) can be identified. These alterations influence the biological behavior, clinical presentations and therapeutic responses, and their full understanding helps to provide appropriate care for these patients.

Corticotropinoma as a Component of Carney Complex

Known germline gene abnormalities cause one-fifth of the pituitary adenomas in children and adolescents, but, in contrast with other pituitary tumor types, the genetic causes of corticotropinomas are largely unknown. In this study, we report a case of Cushing disease (CD) due to a loss-of-function mutation in PRKAR1A, providing evidence for association of this gene with a corticotropinoma. A 15-year-old male presenting with hypercortisolemia was diagnosed with CD. Remission was achieved after surgical resection of a corticotropin (ACTH)-producing pituitary microadenoma, but recurrence 3 years later prompted reoperation and radiotherapy. Five years after the original diagnosis, the patient developed ACTH-independent Cushing syndrome, and a diagnosis of primary pigmented nodular adrenocortical disease was confirmed. A PRKAR1A mutation (c.671delG, p.G225Afs*16) was detected in a germline DNA sample from the patient, which displayed loss of heterozygosity in the corticotropinoma. No other germline or somatic mutations of interest were found. As corticotropinomas are not a known component of Carney complex (CNC), we performed loss of heterozygosity and messenger RNA stability studies in the patient's tissues, and analyzed the effect of Prkar1a silencing on AtT-20/D16v-F2 mouse corticotropinoma cells. No PRKAR1A defects were found among 97 other pediatric CD patients studied. Our clinical case and experimental data support a role for PRKAR1A in the pathogenesis of a corticotroph cell tumor. This is a molecularly confirmed report of a corticotropinoma presenting in association with CNC. We conclude that germline PRKAR1A mutations are a novel, albeit apparently infrequent, cause of CD.

Advances in diagnosis and management of familial pituitary adenomas

Familial pituitary adenomas account for approximately 5–8% of all pituitary adenomas. Besides the adenomas occurring as part of syndromic entities that group several endocrine or nonendocrine disorders (multiple endocrine neoplasia type 1 or 4, Carney complex and McCune–Albright syndrome), 2–3% of familial pituitary adenomas fit into the familial isolated pituitary adenomas (FIPA) syndrome, an autosomal dominant condition with incomplete penetrance. About 20% of FIPA cases are due to mutations in the AIP gene and have distinct clinical characteristics. Recent findings have isolated a new non-AIP FIPA syndrome called X-linked acrogigantism, resulting from a microduplication that always includes the GPR101 gene. These new advances in the field of pituitary disease are opening up a new challenging domain to both clinicians and researchers. This review will focus on these recent findings and their contribution to the diagnosis and the management of familial pituitary adenomas.

17p13.3 microduplication including CRK leads to overgrowth and elevated growth factors: A case report

17p13.3 microduplications classified as class I duplications involving YWHAE but not PAFAH1B1 (formerly LIS1) and class II duplications which extend to involve PAFAH1B1, are associated with diverse phenotypes including intellectual disability and structural brain malformations. We report a girl with an approximately 1.58 Mb apparently terminal gain of 17p13.3, which contains more than 20 genes including the YWHAE and CRK genes (OMIM: 164762). She had increased growth factors accompanied by pathologic tall stature. In addition to these, she developed central precocious puberty at 7 years old. In individuals with class I 17p13.3 microduplications including CRK, we recommend biochemical evaluation of the growth hormone axis. Providers caring for these patients should be aware of their possible risk for the development of central precocious puberty.

Carney complex: an update

Carney complex (CNC) is a rare autosomal dominant syndrome, characterized by pigmented lesions of the skin and mucosa, cardiac, cutaneous and other myxomas and multiple endocrine tumors. The disease is caused by inactivating mutations or large deletions of the PRKAR1A gene located at 17q22-24 coding for the regulatory subunit type I alpha of protein kinase A (PKA) gene. Most recently, components of the complex have been associated with defects of other PKA subunits, such as the catalytic subunits PRKACA (adrenal hyperplasia) and PRKACB (pigmented spots, myxomas, pituitary adenomas). In this report, we review CNC, its clinical features, diagnosis, treatment and molecular etiology, including PRKAR1A mutations and the newest on PRKACA and PRKACB defects especially as they pertain to adrenal tumors and Cushing's syndrome.

Medical and Surgical Management of Carney Complex

Carney complex is a rare, autosomal dominant genetic disorder that consists of multiple myxomatous lesions and endocrine abnormalities, including skin lesions, cardiac myxomas, primary pigmented nodular adrenocortical disease, and acromegaly. This review discusses the medical and surgical treatment of patients with Carney complex.

Familial pituitary tumors

Pituitary adenomas are benign intracranial neoplasms that present a major clinical concern due to hormone overproduction and/or tumor mass effects. The majority of pituitary adenomas occur sporadically; however, familial cases are increasingly being recognized, such as multiple endocrine neoplasia type 1 (MEN1), Carney complex (CNC), and familial isolated pituitary adenoma (FIPA). Familial pituitary tumors appear to differ from their sporadic counterparts both in their genetic basis and in clinical characteristics. Evidence suggests that, especially in MEN1 and FIPA, tumors are more aggressive and affect patients at a younger age, therefore justifying the importance of early diagnosis, while in Carney complex pituitary hyperplasia is common. The genetic alterations responsible for the formation of familial pituitary syndromes include the MEN1 gene, responsible for about 80% of MEN1 cases, the regulatory subunit of the protein kinase A, PRKAR1A, responsible for about 70% of Carney complex cases, and AIP, the gene coding the aryl hydrocarbon receptor interacting protein, responsible for about 20% of FIPA cases. Rarely other genes have also been found responsible for familial pituitary adenoma cases. McCune-Albright syndrome (MAS) also has a genetic origin due to mosaic mutations in the G protein-coupled α subunit coded by the GNAS1 gene. In this chapter, we summarize the genetic and clinical characteristics of these familial pituitary syndromes and MAS.

The complex of myxomas, spotty skin pigmentation and endocrine overactivity (Carney complex): imaging findings with clinical and pathological correlation

The complex of myxomas, spotty skin pigmentation and endocrine overactivity, or Carney complex (CNC), is a familial multiple endocrine neoplasia and lentiginosis syndrome. CNC is inherited in an autosomal dominant manner and is genetically heterogeneous. Its features overlap those of McCune-Albright syndrome and other multiple endocrine neoplasia (MEN) syndromes. Spotty skin pigmentation is the major clinical manifestation of the syndrome, followed by multicentric heart myxomas, which occur at a young age and are the lethal component of the disease. Myxomas may also occur on the skin (eyelid, external ear canal and nipple) and the breast. Breast myxomas, when present, are multiple and bilateral among female CNC patients, an entity which is also described as “breast-myxomatosis” and is a characteristic feature of the syndrome. Affected CNC patients often have tumours of two or more endocrine glands, including primary pigmented nodular adrenocortical disease (PPNAD), an adrenocorticotropin hormone (ACTH)-independent cause of Cushing’s syndrome, growth hormone (GH)-secreting and prolactin (PRL)-secreting pituitary adenomas, thyroid adenomas or carcinomas, testicular neoplasms (large-cell calcifying Sertoli cell tumours [LCCSCT]) and ovarian lesions (cysts and cancinomas). Additional infrequent but characteristic manifestations of CNC are psammomatous melanotic schwannomas (PMS), breast ductal adenomas (DAs) with tubular features, and osteochondromyxomas or “Carney bone tumour”.

Teaching Points

• Almost 60 % of the known CNC kindreds have a germline inactivating mutations in the PRKAR1A gene.

• Spotty skin pigmentation is the major clinical manifestation of CNC, followed by heart myxomas.

• Indicative imaging signs of PPNAD are contour abnormality and hypodense spots within the gland.

• Two breast tumours may present in CNC: myxoid fibroadenomas (breast myxomatosis) and ductal adenomas.

• Additional findings of CNC are psammomatous melanotic schwannomas (PMSs) and osteochondromyxomas.

Functional screen analysis reveals miR-26b and miR-128 as central regulators of pituitary somatomammotrophic tumor growth through activation of the PTEN-AKT pathway

MicroRNAs (miRNAs) have been involved in the pathogenesis of different types of cancer; however, their function in pituitary tumorigenesis remains poorly understood. Cyclic-AMP-dependent protein kinase-defective pituitaries occasionally form aggressive growth-hormone (GH)-producing pituitary tumors in the background of hyperplasia caused by haploinsufficiency of the protein kinase's main regulatory subunit, PRKAR1A. The molecular basis for this development remains unknown. We have identified a 17-miRNA signature of pituitary tumors formed in the background of hyperplasia (caused in half of the cases by PRKAR1A-mutations). We selected two miRNAs on the basis of their functional screen analysis: inhibition of miR-26b expression and upregulation of miR-128 suppressed the colony formation ability and invasiveness of pituitary tumor cells. Furthermore, we identified that miR-26b and miR-128 affected pituitary tumor cell behavior through regulation of their direct targets, PTEN and BMI1, respectively. In addition, we found that miR-128 through BMI1 direct binding on the PTEN promoter affected PTEN expression levels and AKT activity in the pituitary tumor cells. Our in vivo data revealed that inhibition of miR-26b and overexpression of miR-128 could suppress pituitary GH3 tumor growth in xenografts. Taken together, we have identified a miRNA signature for GH-producing pituitary tumors and found that miR-26b and miR-128 regulate the activity of the PTEN-AKT pathway in these tumors. This is the first suggestion of the possible involvement of miRNAs regulating the PTEN-AKT pathway in GH-producing pituitary tumor formation in the context of hyperplasia or due to germline PRKAR1A defects. MiR-26b suppression and miR-128 upregulation could have therapeutic potential in GH-producing pituitary tumor patients.

Hereditary pituitary hyperplasia with infantile gigantism

CONTEXT

We report hereditary pituitary hyperplasia.

OBJECTIVE

The objective of the study was to describe the results of the clinical and laboratory analysis of this rare instance of hereditary pituitary hyperplasia.

DESIGN

The study is a retrospective analysis of three cases from one family.

SETTING

The study was conducted at the National Institutes of Health, a tertiary referral center.

PATIENTS

A mother and both her sons had very early-onset gigantism associated with high levels of serum GH and prolactin.

INTERVENTIONS

The condition was treated by total hypophysectomy.

MAIN OUTCOME MEASURE(S)

We performed clinical, pathological, and molecular evaluations, including evaluation basal and provocative endocrine testing, neuroradiological assessment, and assessment of the pituitary tissue by microscopic evaluation, immunohistochemistry, and electron microscopy.

RESULTS

All three family members had very early onset of gigantism associated with abnormally high serum levels of GH and prolactin. Serum GHRH levels were not elevated in either of the boys. The clinical, radiographic, surgical, and histological findings indicated mammosomatotroph hyperplasia. The pituitary gland of both boys revealed diffuse mammosomatotroph hyperplasia of the entire pituitary gland without evidence of adenoma. Prolactin and GH were secreted by the same cells within the same secretory granules. Western blot and immunohistochemistry demonstrated expression of GHRH in clusters of cells distributed throughout the hyperplastic pituitary of both boys.

CONCLUSIONS

This hereditary condition seems to be a result of embryonic pituitary maldevelopment with retention and expansion of the mammosomatotrophs. The findings suggest that it is caused by paracrine or autocrine pituitary GHRH secretion during pituitary development.

Familial isolated pituitary adenomas: from genetics to therapy

According to autopsy and radiological data, pituitary adenomas (PAs) develop in approximately 15% to 20% of the population. The great majority of PAs arise sporadically and affect adults. Rarely they are diagnosed in children and adolescents. Approximately 5% of cases are thought to be familial. Inherited conditions associated with pituitary tumors include multiple endocrine neoplasia type 1 (MEN-1) and type 4 (MEN-4), (CNC) Carney Complex, and familial isolated PA (FIPA) syndrome. FIPA is an autosomal dominant condition, defined by the presence of two or more patients affected by PAs in the same kindred, and no other associated condition. Germline mutations of the aryl hydrocarbon receptor interacting protein gene located on chromosome 11q13 have been reported in 15%-40% of FIPA cases. In the remaining cases, genetic defect are unidentified. This article focuses on FIPA clinical, pathological, genetic features, and therapeutic management.

[Carney complex]

Carney complex (CNC) is an autosomal dominantly inherited syndrome characterized by spotty skin pigmentation, cardiac and cutaneous myxoma, and endocrine overactivity. Skin pigmentation includes lentigines and blue nevi. Myxomas may occur in breast, skin and heart. Cardiac myxomas may be multiple and occur in any cardiac chamber, and are more prone to recurrence. The most common endocrine gland manifestation is an ACTH-independent Cushing's syndrome due to primary pigmented nodular adrenocortical disease (PPNAD). PPNAD may occur isolated, with no other signs of CNC. Pituitary and thyroid glands and gonads are also involved. The PRKAR1A gene, located in 17 q22-24, encodes type 1A regulatory subunit of protein kinase A. Inactivating germline mutations of this gene are found in 70% of patients with CNC. PRKAR1A is a key component of the c-AMP signaling pathway that has been implicated in endocrine tumorigenesis. Many different mutations have been reported in the PRKAR1A gene. In almost all cases the sequence change was predicted to lead to a premature stop codon and the resultant mutant mRNA was subject to nonsense-mediated mRNA decay. There is no clear genotype-phenotype correlation in patients with CNC. Genetic analysis should be performed in all CNC index cases. All affected patients should be monitored for clinical signs of CNC at least once a year. Genetic diagnosis allows for more effective preparation of more appropriate and effective therapeutic strategies and genetic counseling for patients and gene carriers, and to avoid unnecessary tests to relatives not carrying the gene.

Genetic susceptibility in pituitary adenomas: from pathogenesis to clinical implications

Pituitary adenomas usually present sporadically, with a multifactorial pathogenesis including somatic mutational events in cancer-related genes. Genetic predisposition implies the presence of germline DNA alterations with a range of impacts on pituitary cell biology, translating into a variable penetrance of the disease. Genetic causes must be considered in the presence of specific clinical settings, such as familial occurrence of pituitary adenoma, with or without extrapituitary diseases, and may also be suspected in young patients (<30 years of age) with macroadenomas. We review the clinical implications of genetic predisposition, with special attention on multiple endocrine neoplasia type 1, Carney complex and familial isolated pituitary adenoma. Genetic screening in selected patients with an apparently sporadic disease is also discussed.

Familial pituitary adenomas

Pituitary adenomas are benign intracranial neoplasms that present a major clinical concern because of hormonal overproduction or compression symptoms of adjacent structures. Most arise in a sporadic setting with a small percentage developing as a part of familial syndromes such as multiple endocrine neoplasia type 1 (MEN1), Carney complex (CNC), and the recently described familial isolated pituitary adenomas (FIPA) and MEN-4. While the genetic alterations responsible for the formation of sporadic adenomas remain largely unknown, considerable advances have been made in defining culprit genes in these familial syndromes. Mutations in MEN1 and PRKAR1A genes are found in the majority of MEN1 and CNC patients, respectively. About 15% of FIPA kindreds present with mutations of the aryl hydrocarbon receptor-interacting protein (AIP) gene. Mutations in the CDKN1B gene, encoding p27(Kip)¹ were identified in MEN4 cases. Familial tumours appear to differ from their sporadic counterparts not only in genetic basis but also in clinical characteristics. Evidence suggests that, especially in MEN1 and FIPA, they are more aggressive and affect patients at younger age, therefore justifying the importance of early diagnosis. In this review, we summarize the genetic and clinical characteristics of these familial pituitary adenomas.

Carney complex: Clinical and genetic 2010 update

First described in the mid 1980s, Carney complex is a rare dominantly heritable multiple endocrine neoplasia syndrome that affects endocrine glands as the adrenal cortex, the pituitary and the thyroid. It is associated with many other nonendocrine tumors, including cardiac myxomas, testicular tumors, melanotic schwannoma, breast myxomatosis, and abnormal pigmentation or myxomas of the skin. The Carney complex gene 1 was identified 10 years ago as the regulatory subunit 1A of protein kinase A (PRKAR1A) located at 17q22-24. An inactivating heterozygous germ line mutation of PRKAR1A is observed in about two-thirds of Carney complex patients. This last decade many progresses have been done in the knowledge of this rare disease and its genetics. This review outlines the current state of this knowledge on Carney complex.

The genetics of pituitary adenomas

Pituitary adenomas are one of the most frequent intracranial tumors with a prevalence of clinically-apparent tumors close to 1:1000 of the general population. They are clinically significant because of hormone overproduction and/or tumor mass effects in addition to the need for neurosurgery, medical therapies and radiotherapy. The majority of pituitary adenomas have a sporadic origin with recognized genetic mutations seldom being found; somatotropinomas are an exception, presenting frequent somatic GNAS mutations. In this and other phenotypes, tumorigenesis could possibly be explained by altered function of genes implicated in cell cycle regulation, growth factors or their receptors, cell-signaling pathways, specific hormonal factors or other molecules with still unclear mechanisms of action. Genetic changes, such as allelic loss or gene amplification, and epigenetic changes, usually by promoter methylation, have been implicated in abnormal gene expression, but alternative mechanisms may be present. Familial cases of pituitary adenomas represent 5% of all pituitary tumors. MEN1 mutations cause multiple endocrine neoplasia type 1 (MEN1), while the Carney complex (CNC) is characterized by mutations in the protein kinase A regulatory subunit-1alpha (PRKAR1A) gene or changes in a locus at 2p16. Recently, a MEN1-like condition, MEN4, was found to be related to mutations in the CDKN1B gene. The clinical entity of familial isolated pituitary adenomas (FIPA) is characterized by genetic defects in the aryl hydrocarbon receptor interacting protein (AIP) gene in about 15% of all kindreds and 50% of homogenous somatotropinoma families. Identification of familial cases of pituitary adenomas is important as these tumors may be more aggressive than their sporadic counterparts.

Familial pituitary tumor syndromes

The vast majority of pituitary tumors are benign and occur sporadically; however, they can still result in significant morbidity and even premature mortality through mass effects and hormone dysfunction. The etiology of sporadic tumors is still poorly understood; by contrast, advances have been made in our understanding of familial pituitary adenoma syndromes in the past decade. Currently, four genes are known to be associated with familial pituitary tumor syndromes: MEN1, CDKN1B, PRKAR1A and AIP. The first three genes are associated with a variety of extrapituitary pathologies, for example, primary hyperparathyroidism with multiple endocrine neoplasia type 1, which might aid identification of these syndromes. By contrast, AIP mutations seem to occur in the setting of isolated familial pituitary adenomas, particularly of the growth-hormone-secreting subtype. Awareness and identification of familial pituitary tumor syndromes is important because of potential associated pathologies and important implications for family members. Here, we review the current knowledge of familial pituitary tumor syndromes.

Advances in the Diagnosis, Treatment, and Molecular Genetics of Pituitary Adenomas in Childhood

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Large genomic deletions in AIP in pituitary adenoma predisposition

CONTEXT

Germline mutations in AIP have been recently shown to cause pituitary adenoma predisposition (PAP). Subsequently, many intragenic germline mutations have been reported, both in familial and in sporadic settings.

OBJECTIVE

Our objective was to evaluate the possible contribution of large genomic germline AIP deletions, an important mutation type in tumor predisposition syndromes, in PAP.

DESIGN

Here, we applied the multiplex ligation-dependent probe amplification assay to examine whether large genomic AIP or MEN1 alterations account for a subset of PAP cases.

PATIENTS

The study was performed on familial and sporadic pituitary adenoma cases of European origin, which had previously tested negative for germline AIP and MEN1 mutations by sequencing.

RESULTS

Two of 21 pituitary adenoma families (9.5%) were found to harbor an AIP deletion. No copy number changes were detected among 67 sporadic pituitary adenoma patients. No MEN1 deletions were found.

CONCLUSIONS

The present study shows that large genomic AIP deletions account for a subset of PAP. Therefore, in suspected PAP cases undergoing counseling and AIP genetic testing, multiplex ligation-dependent probe amplification could be considered if direct sequencing does not identify a mutation.

Curcumin (diferuloylmethane) inhibits cell proliferation, induces apoptosis, and decreases hormone levels and secretion in pituitary tumor cells

Prolactinomas are the most prevalent functional pituitary adenomas. Dopamine D2 receptor (D2R) agonists, such as bromocriptine are the first line of therapy; however, drug intolerance/resistance to D2R agonists exists. Apart from D2R agonists, there is no established medical therapy for prolactinomas; therefore, identifying novel therapeutics is warranted. Curcumin, a commonly used food additive in South Asian cooking, inhibits proliferation of several tumor cell lines; however, its effect on pituitary tumor cell proliferation has not been determined. Our objectives were to: 1) determine whether curcumin inhibits proliferation of pituitary tumor cell lines; 2) identify the signaling intermediaries that mediate the effect of curcumin; 3) examine whether curcumin inhibited pituitary hormone production and release; and 4) examine whether curcumin could enhance the growth-inhibitory effect of bromocriptine. Using rat lactotroph cell lines, GH3 and MMQ cells, we report that curcumin had a robust dose and time-dependent inhibitory effect on GH3 and MMQ cell proliferation. Inhibitory effects of curcumin persisted, even on removal of curcumin, and curcumin also blocked colony formation ability of pituitary tumor cells. The growth-inhibitory effect of curcumin was accompanied by decreased expression of cyclin D3 and ser 780 phosphorylation of retinoblastoma protein. In addition, curcumin also induced apoptosis in both GH3 and MMQ cells. Furthermore, curcumin suppresses intracellular levels and release of both prolactin and GH. Finally, we show that low concentrations of curcumin enhanced the growth-inhibitory effect of bromocriptine on MMQ cell proliferation. Taken together we demonstrate that curcumin inhibits pituitary tumor cell proliferation, induces apoptosis, and decreases hormone production and release, and thus, we propose developing curcumin as a novel therapeutic tool in the management of prolactinomas.

Pituitary tumors in childhood: update of diagnosis, treatment and molecular genetics

Pituitary tumors are rare in childhood and adolescence, with a reported prevalence of up to one per 1 million children. Only 2-6% of surgically treated pituitary tumors occur in children. Although pituitary tumors in children are almost never malignant and hormonal secretion is rare, these tumors may result in significant morbidity. Tumors within the pituitary fossa are mainly of two types: craniopharyngiomas and adenomas. Craniopharyngiomas cause symptoms by compressing normal pituitary, causing hormonal deficiencies and producing mass effects on surrounding tissues and the brain; adenomas produce a variety of hormonal conditions such as hyperprolactinemia, Cushing disease and acromegaly or gigantism. Little is known about the genetic causes of sporadic lesions, which comprise the majority of pituitary tumors, but in children, more frequently than in adults, pituitary tumors may be a manifestation of genetic conditions such as multiple endocrine neoplasia type 1, Carney complex, familial isolated pituitary adenoma and McCune-Albright syndrome. The study of pituitary tumorigenesis in the context of these genetic syndromes has advanced our knowledge of the molecular basis of pituitary tumors and may lead to new therapeutic developments.

Clinical and molecular genetics of acromegaly: MEN1, Carney complex, McCune-Albright syndrome, familial acromegaly and genetic defects in sporadic tumors

Pituitary tumors are among the most common neoplasms in man; they account for approximately 15% of all primary intracranial lesions (Jagannathan et al., Neurosurg Focus, 19:E4, 2005). Although almost never malignant and rarely clinically expressed, pituitary tumors may cause significant morbidity in affected patients. First, given the critical location of the gland, large tumors may lead to mass effects, and, second, proliferation of hormone-secreting pituitary cells leads to endocrine syndromes. Acromegaly results from oversecretion of growth hormone (GH) by the proliferating somatotrophs. Despite the significant efforts made over the last decade, still little is known about the genetic causes of common pituitary tumors and even less is applied from this knowledge therapeutically. In this review, we present an update on the genetic syndromes associated with pituitary adenomas and discuss the related genetic defects. We next review findings on sporadic, non-genetic, pituitary tumors with an emphasis on pathways and animal models of pituitary disease. In conclusion, we attempt to present an overall, integrative approach to the human molecular genetics of both familiar and sporadic pituitary tumors.

Molecular genetics of the cAMP-dependent protein kinase pathway and of sporadic pituitary tumorigenesis

Pituitary tumors are among the most common human neoplasms. Although these common lesions rarely become clinically manifest and they are almost never malignant, they are the cause of significant morbidity in affected patients. The genetic causes of common pituitary tumors remain for the most part unknown; progress has been limited to the elucidation of the molecular etiology of four genetic syndromes predisposing to pituitary neoplasias: McCune-Albright syndrome, multiple endocrine neoplasia type 1, Carney complex and, most recently, familial acromegaly and prolactinomas and other tumors caused by mutations in the GNAS, menin, PRKAR1A, AIP, and p27 (CDKN1B) genes, respectively. Intense molecular studies of sporadic pituitary tumors from patients with negative family histories and no other neoplasms have yielded interesting findings with abnormalities in growth factor expression and cell cycle control dysregulation. To add to the difficulties in understanding pituitary tumorigenesis in man, good murine models of these neoplasms simply do not exist: pituitary tumors are common in rodents, but their histologic origin (mostly from the intermediate lobe), age of presentation (late in murine life) and clinical course make them hardly models of their human counterparts. The present report reviews the clinical and molecular genetics of the cAMP-dependent protein kinase pathway in human pituitary tumors; it also reviews briefly other pathways that have been involved in sporadic pituitary neoplasms. At the end, we attempt a unifying hypothesis for pituitary tumorigenesis, taking into account data that are also discussed elsewhere in this issue.