Multiple endocrine neoplasia type 1-associated thyrotropin-producing pituitary carcinoma: report of a probable de novo example

Molecular and Clinical Spectrum of Primary Hyperparathyroidism

Recent data suggest an increase in the overall incidence of parathyroid disorders, with primary hyperparathyroidism (PHPT) being the most prevalent parathyroid disorder. PHPT is associated with morbidities (fractures, kidney stones, chronic kidney disease) and increased risk of death. The symptoms of PHPT can be nonspecific, potentially delaying the diagnosis. Approximately 15% of patients with PHPT have an underlying heritable form of PHPT that may be associated with extraparathyroidal manifestations, requiring active surveillance for these manifestations as seen in multiple endocrine neoplasia type 1 and 2A. Genetic testing for heritable forms should be offered to patients with multiglandular disease, recurrent PHPT, young onset PHPT (age ≤40 years), and those with a family history of parathyroid tumors. However, the underlying genetic cause for the majority of patients with heritable forms of PHPT remains unknown. Distinction between sporadic and heritable forms of PHPT is useful in surgical planning for parathyroidectomy and has implications for the family. The genes currently known to be associated with heritable forms of PHPT account for approximately half of sporadic parathyroid tumors. But the genetic cause in approximately half of the sporadic parathyroid tumors remains unknown. Furthermore, there is no systemic therapy for parathyroid carcinoma, a rare but potentially fatal cause of PHPT. Improved understanding of the molecular characteristics of parathyroid tumors will allow us to identify biomarkers for diagnosis and novel targets for therapy.

Recent Therapeutic Advances in Pituitary Carcinoma

Pituitary carcinoma (PC) is a rare, aggressive malignancy that comprises 0.1-0.2% of all pituitary tumors. PC is defined anatomically as a pituitary tumor that metastasizes outside the primary intrasellar location as noncontiguous lesions in the central nervous system or as metastases to other organs. Similar to pituitary adenoma, PC originates from various cell types of the pituitary gland and can be functioning or nonfunctioning, with the former constituting the majority of the cases. Compression of intricate skull-based structures, excessive hormonal secretion, impaired pituitary function from therapy, and systemic metastases lead to debilitating symptoms and a poor survival outcome in most cases. PC frequently recurs despite multimodality treatments, including surgical resection, radiotherapy, and biochemical and cytotoxic treatments. There is an unmet need to better understand the pathogenesis and molecular characterization of PC to improve therapeutic strategies. As our understanding of the role of signaling pathways in the tumorigenesis of and malignant transformation of PC evolves, efforts have focused on targeted therapy. In addition, recent advances in the use of immune checkpoint inhibitors to treat various solid cancers have led to an interest in exploring the role of immunotherapy for the treatment of aggressive refractory pituitary tumors. Here, we review our current understanding of the pathogenesis, molecular characterization, and treatment of PC. Particular attention is given to emerging treatment options, including targeted therapy, immunotherapy, and peptide receptor radionuclide therapy.

Natural history of pituitary carcinoma with metastasis to the cervical spine: illustrative case

BACKGROUND

Pituitary carcinoma is a rare tumor of the adenohypophysis with noncontiguous craniospinal dissemination and/or systemic metastases. Given the rarity of this malignancy, there is limited knowledge and consensus regarding its natural history, prognosis, and optimal treatment.

OBSERVATIONS

The authors present the case of a 46-year-old woman initially treated with invasive prolactin-secreting pituitary macroadenoma who developed metastatic disease of the cervical spine 6 years later. The patient presented with acutely worsening compressive cervical myelopathy and required posterior cervical decompression, tumor resection, and instrumented arthrodesis for posterolateral fusion.

LESSONS

This case underscores the importance of long-term monitoring of hormone levels and having a high clinical suspicion for metastatic disease to the spine in patients presenting with acute myelopathy or radiculopathy in the setting of previously treated invasive secreting pituitary adenoma.

Multiple Endocrine Neoplasia Type 1: Latest Insights

Multiple endocrine neoplasia type 1 (MEN1), a rare tumor syndrome that is inherited in an autosomal dominant pattern, is continuing to raise great interest for endocrinology, gastroenterology, surgery, radiology, genetics, and molecular biology specialists. There have been 2 major clinical practice guidance papers published in the past 2 decades, with the most recent published 8 years ago. Since then, several new insights on the basic biology and clinical features of MEN1 have appeared in the literature, and those data are discussed in this review. The genetic and molecular interactions of the MEN1-encoded protein menin with transcription factors and chromatin-modifying proteins in cell signaling pathways mediated by transforming growth factor β/bone morphogenetic protein, a few nuclear receptors, Wnt/β-catenin, and Hedgehog, and preclinical studies in mouse models have facilitated the understanding of the pathogenesis of MEN1-associated tumors and potential pharmacological interventions. The advancements in genetic diagnosis have offered a chance to recognize MEN1-related conditions in germline MEN1 mutation-negative patients. There is rapidly accumulating knowledge about clinical presentation in children, adolescents, and pregnancy that is translatable into the management of these very fragile patients. The discoveries about the genetic and molecular signatures of sporadic neuroendocrine tumors support the development of clinical trials with novel targeted therapies, along with advancements in diagnostic tools and surgical approaches. Finally, quality of life studies in patients affected by MEN1 and related conditions represent an effort necessary to develop a pharmacoeconomic interpretation of the problem. Because advances are being made both broadly and in focused areas, this timely review presents and discusses those studies collectively.

The clinical aspects of pituitary tumour genetics

BACKGROUND

Pituitary tumours are usually benign and relatively common intracranial tumours, with under- and overexpression of pituitary hormones and local mass effects causing considerable morbidity and increased mortality. While most pituitary tumours are sporadic, around 5% of the cases arise in a familial setting, either isolated [familial isolated pituitary adenoma, related to AIP or X-linked acrogigantism], or in a syndromic disorder, such as multiple endocrine neoplasia type 1 or 4, Carney complex, McCune-Albright syndrome, phaeochromocytoma/paraganglioma with pituitary adenoma, DICER1 syndrome, Lynch syndrome, and USP8-related syndrome. Genetically determined pituitary tumours usually present at younger age and show aggressive behaviour, and are often resistant to different treatment modalities.

SUBJECT

In this practical summary, we take a practical approach: which genetic syndromes should be considered in case of different presentation, such as tumour type, family history, age of onset and additional clinical features of the patient.

CONCLUSION

The identification of the causative mutation allows genetic and clinical screening of relatives at risk, resulting in earlier diagnosis, a better therapeutic response and ultimately to better long-term outcomes.

Aggressive Cushing's Disease: Molecular Pathology and Its Therapeutic Approach

Cushing's disease is a syndromic pathological condition caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (ACTHomas) mediated by hypercortisolemia. It may have a severe clinical course, including infection, psychiatric disorders, hypercoagulability, and metabolic abnormalities, despite the generally small, nonaggressive nature of the tumors. Up to 20% of ACTHomas show aggressive behavior, which is related to poor surgical outcomes, postsurgical recurrence, serious clinical course, and high mortality. Although several gene variants have been identified in both germline and somatic changes in Cushing's disease, the pathophysiology of aggressive ACTHomas is poorly understood. In this review, we focused on the aggressiveness of ACTHomas, its pathology, the current status of medical therapy, and future prospects. Crooke's cell adenoma (CCA), Nelson syndrome, and corticotroph pituitary carcinoma are representative refractory pituitary tumors that secrete superphysiological ACTH. Although clinically asymptomatic, silent corticotroph adenoma is an aggressive ACTH-producing pituitary adenoma. In this review, we summarize the current understanding of the pathophysiology of aggressive ACTHomas, including these tumors, from a molecular point of view based on genetic, pathological, and experimental evidence. The treatment of aggressive ACTHomas is clinically challenging and usually resistant to standard treatment, including surgery, radiotherapy, and established medical therapy (e.g., pasireotide and cabergoline). Temozolomide is the most prescribed pharmaceutical treatment for these tumors. Reports have shown that several treatments for patients with refractory ACTHomas include chemotherapy, such as cyclohexyl-chloroethyl-nitrosourea combined with 5-fluorouracil, or targeted therapies against several molecules including vascular endothelial growth factor receptor, cytotoxic T lymphocyte antigen 4, programmed cell death protein 1 (PD-1), and ligand for PD-1. Genetic and experimental evidence indicates that some possible therapeutic candidates are expected, such as epidermal growth factor receptor tyrosine kinase inhibitor, cyclin-dependent kinase inhibitor, and BRAF inhibitor. The development of novel treatment options for aggressive ACTHomas is an emerging task.

Malignancy course of pituitary adenoma in MEN1 syndrome: Clinical-Neuroradiological signs

Pituitary carcinomas (PCa) are extremely rare, indistinguishable from pituitary adenomas on histopathological grounds and have a poor prognosis. Most PCa start as PRL or ACTH secreting tumors in males, with relapsing invasive behaviour, refractoriness to medical and radiotherapy and increasing hormonal levels. The presence of distant metastases is still required for the diagnosis of PCa. The association with genetic endocrine diseases must be taken into account, since it adds further risk of evolution towards malignancy. Intradural spinal metastases have also been reported, so a complete craniospinal MR evaluation is recommended, when clinically indicated. We report a case of PCa, associated with MEN1 syndrome, with evidence of meningeal spread to the tentorium cerebelli, clival dura and spinal drop metastases mimicking spinal nerves schwannomas.

The Impact of Diet on Breast Cancer Outcomes

PURPOSE OF REVIEW

Breast cancer is the most common cancer in women, yet conclusive evidence of the effects of dietary modification in breast cancer survivors is lacking. Here, we summarize the literature and highlight important data regarding the association between dietary interventions and breast cancer outcomes.

RECENT FINDINGS

Long-term follow-up and secondary analysis of the Women's Health Initiative study demonstrated a significant improvement in overall survival for women who were randomized to the low-fat diet pattern compared with those in the usual-diet group. Dietary quality as measured by Healthy Eating Index score was also associated with both a decrease in cancer-specific mortality and overall mortality. Despite current evidence on the role of diet and nutrition in breast cancer outcomes, conclusive data to translate current findings to clinical practice is lacking and requires multidisciplinary prospective research to advance the field.

Pituitary carcinoma: Two case reports and review of literature

BACKGROUND

Pituitary carcinoma is a rare type of malignancy that can be very difficult to diagnose and treat. Many cases were diagnosed at autopsy. Delays in diagnosis often adversely impact patients' outcomes. Even with prompt diagnosis, treatment decisions remain challenging in the absence of randomized controlled trials.

CASE SUMMARY

We report two cases of pituitary carcinoma in men with a history of pituitary adenoma. In the first case, a 55-year-old man was initially diagnosed with pituitary macroadenoma. He underwent subtotal debulking of the tumor followed by adjuvant radiotherapy. Subsequently, he developed relapsed disease and multifocal intracranial metastases and a diagnosis of pituitary carcinoma was rendered. He passed away despite several lines of systemic therapies including temozolomide, lomustine and bevacizumab. Another 52-year-old man was diagnosed with atypical pituitary adenoma with presentation of sudden onset of vision loss in the right eye. He had recurrent pituitary carcinoma with spinal metastases, treated with surgery, radiation and temozolomide.

CONCLUSION

Pituitary carcinoma is a rare neoplasm with poor prognosis that is difficult to diagnose and treat. The small number of cases restricts our ability to design randomized clinical trials. Management is largely driven by retrospective studies and case series. Establishing molecular biomarkers and comprehensive genomic profiling could help in decisions about diagnosis and management of pituitary carcinoma.

Phenotypes Associated With MEN1 Syndrome: A Focus on Genotype-Phenotype Correlations

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant inherited tumor syndrome, associated with parathyroid, pituitary, and gastro-entero-pancreatic (GEP) neuroendocrine tumors (NETs). MEN1 is usually consequent to different germline and somatic mutations of the MEN1 tumor suppressor gene, although phenocopies have also been reported. This review analyzed main biomedical databases searching for reports on MEN1 gene mutations and focused on aggressive and aberrant clinical manifestations to investigate the potential genotype-phenotype correlation. Despite efforts made by several groups, this link remains elusive to date and evidence that aggressive or aberrant clinical phenotypes may be related to specific mutations has been provided by case reports and small groups of MEN1 patients or families. In such context, a higher risk of aggressive tumor phenotypes has been described in relation to frameshift and non-sense mutations, and predominantly associated with aggressive GEP NETs, particularly pancreatic NETs. In our experience a novel heterozygous missense mutation at c.836C>A in exon 6 was noticed in a MEN1 patient operated for macro-prolactinoma, who progressively developed recurrent parathyroid adenomas, expanding gastrinomas and, long after the first MEN1 manifestation, a neuroendocrine uterine carcinoma. In conclusion, proof of genotype-phenotype correlation is limited but current evidence hints at the need for long-term interdisciplinary surveillance in patients with aggressive phenotypes and genetically confirmed MEN1.

Genetics of Pituitary Tumours

Pituitary tumours are relatively common in the general population. Most often they occur sporadically, with somatic mutations accounting for a significant minority of somatotroph and corticotroph adenomas. Pituitary tumours can also develop secondary to germline mutations as part of a complex syndrome or as familial isolated pituitary adenomas. Tumours occurring in a familial setting may present at a younger age and can behave more aggressively with resistance to treatment. This chapter will focus on the genetics and molecular pathogenesis of pituitary tumours.

Surgery, Octreotide, Temozolomide, Bevacizumab, Radiotherapy, and Pegvisomant Treatment of an AIP Mutation‒Positive Child

CONTEXT

Inactivating germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene are linked to pituitary adenoma predisposition. Here, we present the youngest known patient with AIP-related pituitary adenoma.

CASE DESCRIPTION

The patient presented at the age of 4 years with pituitary apoplexy and left ptosis with severe visual loss following a 1-year history of abdominal pain, headaches, and rapid growth. His IGF-1 level was 5× the upper limit of normal, and his random GH level was 1200 ng/mL. MRI showed a 43 × 24 × 35‒mm adenoma with suprasellar extension invading the left cavernous sinus (Knosp grade 4). After transsphenoidal surgery, histology showed a grade 2A sparsely granulated somatotropinoma with negative O6-methylguanine-DNA methyltransferase and positive vascular endothelial growth factor staining. Genetic testing identified a heterozygous germline nonsense AIP mutation (p.Arg81Ter). Exome sequencing of the tumor revealed that it had lost the entire maternal chromosome-11, rendering it hemizygous for chromosome-11 and therefore lacking functional copies of AIP in the tumor. He was started on octreotide, but because the tumor rapidly regrew and IGF-1 levels were unchanged, temozolomide was initiated, and intensity-modulated radiotherapy was administered 5 months after surgery. Two months later, bevacizumab was added, resulting in excellent tumor response. Although these treatments stabilized tumor growth over 4 years, IGF-1 was normalized only after pegvisomant treatment, although access to this medication was intermittent. At 3.5 years of follow-up, gamma knife treatment was administered, and pegvisomant dose increase was indicated.

CONCLUSION

Multimodal treatment with surgery, long-acting octreotide, radiotherapy, temozolomide, bevacizumab, and pegvisomant can control genetically driven, aggressive, childhood-onset somatotropinomas.

Identification of Novel Genes Involved in the Pathogenesis of an ACTH-Secreting Pituitary Carcinoma: A Case Report and Literature Review

Pituitary carcinomas (PCs) is considerable uncommon entities with a poor prognosis that represents only 0. 1–0.2% of all pituitary tumors. There are fewer than 150 reported cases up to now. In addition, the molecular pathogenesis leading to malignant pituitary transformation remain unclear due to the rarity of PCs. Here we present an uncommon case of ACTH-secreting PCs and explore the gene mutation following pituitary adenoma transformation. Our detailed clinical, histopathological and molecular detection data suggest that novel genes of ATRX and PTEN were implicated in the pathogenesis of PCs by searching Pubmed and the Web of Science databases as well as Cosmic databank. To the best of our knowledge, this is the first documented rare PCs patient with novel gene mutations that included ATRX and PTEN in addition to TP53. Present finding may therefore provide significant information for targeted therapy of PCs.

Aggressive and malignant pituitary tumours: state-of-the-art

Pituitary adenomas are unique in multiple ways. They are rarely malignant in terms of metastases; yet, they may be aggressive. Their cancerous potential is defined in a classic oncological way by the ability to metastasise, and therefore, it has been crucial to differentiate this process from aggressive behaviour, characterised as a particularly invasive and/or recurrent behaviour and resistance to common modalities of therapy. Recently, however, important changes have been introduced to the diagnosis and management of aggressive and malignant pituitary tumours including the 4th edition of the World Health Organization (WHO) classification for endocrine tumours (2017) as well as ESE Clinical Guidelines (2018), although an attempt to establish predictive and/or prognostic markers of clinical aggressiveness remains difficult. In this review, we focus on a group of pituitary tumours causing significant problems in clinical practice and requiring multidisciplinary input. We summarise updates in definitions of tumour invasiveness, aggressiveness and malignant transformation, as well as histological classification, and emphasise the new considerations regarding aggressive and malignant potential and its relationship to therapeutic strategies.

Corticotrophic pituitary carcinoma with cervical metastases: case series and literature review

PURPOSE

Pituitary tumors are the second most common intracranial tumors, however, pituitary carcinoma is a rare clinical entity which represents only 0.1-0.2% of all pituitary tumors. Diagnosis of pituitary carcinoma requires the presence of metastasis. Early identification of pituitary carcinoma is difficult, and only recently have guidelines been published for the treatment of aggressive pituitary tumors. We present two cases from our institution, with a review of other cases available in literature in order to better characterize this rare disease.

METHODS

A retrospective review of two patients with pituitary carcinoma treated at a tertiary medical center was performed. The MEDLINE database was searched for all cases of pituitary carcinoma. Information for age at diagnosis, sex, pituitary tumor type, latency period from pituitary tumor to presentation of carcinoma, sites of metastasis, number of surgical therapies, radiation and chemotherapy, and survival after diagnosis were collected.

RESULTS

A total of 69 studies were available for review for a total of 72 unique cases. The average age at diagnosis was 46.3 years. The most common tumors were ACTH-secreting (34.7%), Prolactin-secreting (23.6%), and Null Cell (15.3%). The average latency period from pituitary tumor diagnosis to metastasis was 9 years. All patients underwent surgical therapy during their treatment, with an average of 2.76 procedures. The mortality rate was 54.8% with average time to death after diagnosis of approximately 10 months.

CONCLUSIONS

Pituitary carcinoma is a rare disease with high mortality rate and is a diagnostic and treatment challenge. Further study is required but is difficult due to its low incidence.

MEN1 in children and adolescents: Data from patients of a regional referral center for hereditary endocrine tumors

PURPOSE

To retrospectively evaluate the age of onset of MEN1-associated lesions in a group of affected children and adolescents and to compare the clinical features of our series with the evidence derived from the literature.

METHODS

The study population consisted of 22 Italian children and adolescents (age 6-31 years at the time of the inclusion in this study) all with a clinical and/or a genetic diagnosis of MEN1 performed before the age of 16 who have been followed-up regularly from 1998 to 2016 at the Regional Referral Center for Hereditary Endocrine Tumors. Clinical, biochemical, imaging and genetic data have been collected for each patient.

RESULTS

Ten subjects (45.5%) have not yet presented any clinical/biochemical/radiological manifestation of MEN1 disease, whereas 12 patients (54.5%) developed at least one MEN1-associated endocrine manifestation. The second group of patients was significantly older than the first one. The most frequent manifestation was primary hyperparathyroidism (50%), followed by pituitary tumors (prolactinomas) (31.8%) and nonfunctioning pancreatic neuroendocrine tumors (9%). The earliest cases of primary hyperparathyroidism and prolactinoma were a 12-year-old girl and a 13-year-old boy, respectively.

CONCLUSIONS

MEN1 disease seems to present with different features in children and adolescents from those in adults. Our study confirms the fundamental importance of screening for tumors in young MEN1 patients beginning in early childhood, in order to avoid diagnostic and therapeutic delays.

Pituitary Carcinoma in a Patient with an SDHB Mutation

We present the first case of pituitary carcinoma occurring in a patient with a succinate dehydrogenase subunit B (SDHB) mutation and history of paraganglioma. She was initially treated for a glomus tumour with external beam radiotherapy. Twenty-five years later, she was diagnosed with a non-functioning pituitary adenoma, having developed bitemporal hemianopia. Recurrence of the pituitary lesion (Ki-67 10% and p53 overexpressed) occurred 5 years after her transsphenoidal surgery, for which she underwent two further operations followed by radiotherapy. Histology showed large cells with vacuolated clear cytoplasm with positive immunostaining for steroidogenic factor 1 (SF1) and negative staining for pituitary hormones. Four years after the pituitary radiotherapy, two metastatic deposits were identified: a foramen magnum lesion and an intradural extra-medullary cervical lesion at the level of C3/C4. There was also significant growth of the primary pituitary lesion with associated visual deterioration. A biopsy of the foramen magnum lesion, demonstrating cells with vacuolated, clear cytoplasm and positive SF1 staining confirmed a pituitary carcinoma, for which she was commenced on temozolomide chemotherapy. There was dramatic clinical improvement after three cycles and reduction in the size of the lesions was observed following six cycles of temozolomide, and further shrinkage after 10 cycles. The plan is for a total of 12 cycles of temozolomide chemotherapy. SDH mutation-related pituitary tumours have an aggressive phenotype which, in this case, led to metastatic disease. SF1 immunostaining was helpful to identify the tissue origin of the metastatic deposit and to confirm the pituitary carcinoma.

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.

Orbital metastasis of pituitary growth hormone secreting carcinoma causing lateral gaze palsy

Background:

Although pituitary adenoma is one of the most common intracranial tumors, it rarely progresses secondarily into a metastatic carcinoma. Commonalities in reported cases include subtotal resection at presentation, treatment with radiation therapy, and delayed metastatic progression. Pathologic descriptions of these lesions are varying and inconsistent.

Case Description:

A 52-year-old male was diagnosed with acromegaly and pituitary tumor in 1996. He underwent four subtotal resections and five courses of stereotactic radiosurgery over 14 years. He developed left eye lateral gaze palsy, and was found to have a distant orbital metastasis with involvement of the left lateral rectus and lateral orbital wall. He underwent left orbital craniotomy via eyebrow incision for resection of this lesion. Pathologic evaluation showed a markedly elevated Ki67 level of 30%.

Conclusion:

While overall incidence of metastatic progression of pituitary adenoma after radiotherapy appears to be low, it appears to be a possible complication, and could be more likely in patients receiving multiple doses of radiotherapy. Our review of reported cases showed that 45/46 (97.8%) of patients developing carcinoma had prior radiation exposure. These patients may also have more aggressive pathologic characteristics of their lesions.

Pituitary tumors in patients with MEN1 syndrome

We briefly review the characteristics of pituitary tumors associated with multiple endocrine neoplasia type 1. Multiple endocrine neoplasia type 1 is an autosomal-dominant disorder most commonly characterized by tumors of the pituitary, parathyroid, endocrine-gastrointestinal tract, and pancreas. A MEDLINE search for all available publications regarding multiple endocrine neoplasia type 1 and pituitary adenomas was undertaken. The prevalence of pituitary tumors in multiple endocrine neoplasia type 1 may vary from 10% to 60% depending on the studied series, and such tumors may occur as the first clinical manifestation of multiple endocrine neoplasia type 1 in 25% of sporadic and 10% of familial cases. Patients were younger and the time between initial and subsequent multiple endocrine neoplasia type 1 endocrine lesions was significantly longer when pituitary disease was the initial manifestation of multiple endocrine neoplasia type 1. Tumors were larger and more invasive and clinical manifestations related to the size of the pituitary adenoma were significantly more frequent in patients with multiple endocrine neoplasia type 1 than in subjects with non-multiple endocrine neoplasia type 1. Normalization of pituitary hypersecretion was much less frequent in patients with multiple endocrine neoplasia type 1 than in subjects with non-multiple endocrine neoplasia type 1. Pituitary tumors in patients with multiple endocrine neoplasia type 1 syndrome tend to be larger, invasive and more symptomatic, and they tend to occur in younger patients when they are the initial presentation of multiple endocrine neoplasia type 1.

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 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.