Silent corticotroph adenomas

How to standardize the diagnostic approach to pituitary neuroendocrine tumors

Pituitary tumors present heterogeneous biochemical, clinico-radiological, and histological features. Although histologically benign, a non-negligible number of cases present an unpredictable aggressive behavior with local invasiveness, partial/complete resistance to treatment and/or recurrence after surgery, and, rarely, metastasize, overall leading to a significant increase of morbidity, and, thus, requiring skilled multidisciplinary management in referral Centers. Histopathological diagnosis is essential to stratify cancer patient risk and uniform follow-up among Centers. Classification of pituitary neoplasia is continuously evolving in relation to the increased knowledge of mechanisms underlying adenohypophyseal cell tumorigenesis, and the attempts of combining clinico-radiological, biochemical, intraoperative, histological, and molecular elements, with the aim of identifying aggressive forms through. An integrated standardized histopathological report has been proposed in 2019 by the European Pituitary Pathology Group, based on the indications of the 2017 WHO classification of pituitary tumors. The last edition of the WHO Classification of Central Nervous System Tumors and of Endocrine and Neuroendocrine Tumors brought substantial novelties: 1) the replacement of the term "adenoma" with "Pituitary Neuroendocrine Tumor" (PitNET), and of "carcinoma" with "metastatic PitNET," and the consequent ICD-11 recoding from benign to malignant disease; and 2) the pivotal role of lineage restricted pituitary transcription factors for histological typing and subtyping. However, this approach does not reflect the spectrum of tumor phenotypes based on hormone secretion, nor include molecular features. Efforts of interdisciplinary groups of pituitary experts should be strongly encouraged to better understand factors involved in PitNETs evolution and, consequently, standardize diagnosis and reporting based on the most recent knowledges, essential to stratify cancer patient risk and uniform follow-up among centers.

Current opinion on the diagnosis and management of non-functioning pituitary adenomas

INTRODUCTION

Non-functioning pituitary adenomas (NFPAs) are clinically silent tumors and the second most common pituitary adenoma. Surgery is the mainstay of treatment as there is, as yet, no effective medical treatment.

AREAS COVERED

We present current knowledge on the clinical diagnosis, histopathological classification, molecular data, and management strategies in NFPA.

EXPERT OPINION

NFPA is a heterogeneous group of tumors, in respect to their origin and clinical course. In recent years, research on pathology and molecular biology have advanced our knowledge of NFPA pathogenesis. NFPA exhibit, in the majority of cases, an indolent behavior, with satisfactory response to treatment. In aggressive cases, multimodal management is needed; however, even this approach may be insufficient, so the development of new treatments is warranted for better management. In this setting, the understanding of the mechanisms involved in the genesis and progression of NFPA is crucial for the identification and development of directed treatments with higher chances of response.

Aggressive pituitary neuroendocrine tumors: current practices, controversies, and perspectives, on behalf of the EANS skull base section

Aggressive pituitary neuroendocrine tumors (APT) account for 10% of pituitary tumors. Their management is a rapidly evolving field of clinical research and has led pituitary teams to shift toward a neuro-oncological-like approach. The new terminology "Pituitary neuroendocrine tumors" (PitNet) that was recently proposed to replace "pituitary adenomas" reflects this change of paradigm. In this narrative review, we aim to provide a state of the art of actual knowledge, controversies, and recommendations in the management of APT. We propose an overview of current prognostic markers, including the recent five-tiered clinicopathological classification. We further establish and discuss the following recommendations from a neurosurgical perspective: (i) surgery and multi-staged surgeries (without or with parasellar resection in symptomatic patients) should be discussed at each stage of the disease, because it may potentialize adjuvant medical therapies; (ii) temozolomide is effective in most patients, although 30% of patients are non-responders and the optimal timeline to initiate and interrupt this treatment remains questionable; (iii) some patients with selected clinicopathological profiles may benefit from an earlier local radiotherapy and/or chemotherapy; (iv) novel therapies such as VEGF-targeted therapies and anti-CTLA-4/anti-PD1 immunotherapies are promising and should be discussed as 2nd or 3rd line of treatment. Finally, whether neurosurgeons have to operate on "pituitary adenomas" or "PitNets," their role and expertise remain crucial at each stage of the disease, prompting our community to deal with evolving concepts and therapeutic resources.

Multidisciplinary protocol of preoperative and surgical management of patients with pituitary tumors candidates to pituitary surgery

The optimal planning of preoperative diagnosis, management and treatment of pituitary tumors (PT) candidates to pituitary surgery (PS) requires a multidisciplinary approach involving a team of endocrinologists, neurosurgeons, ENT, neuro-ophthalmologists and neuroradiologists with experience in pituitary diseases. Such teams improve surgical results, minimize complications and facilitate their correct treatment if occurring, and optimize the hormonal, ophthalmological and radiological preoperative and follow-up evaluation. We have developed a clinical practice protocol for patients with PT who are candidates to PS based on the most recent national and international guidelines and the relevant literature regarding PT published in the last years. The protocol has been elaborated by a multidisciplinary team of a Spanish Pituitary Tumor Center of Excellence (PTCE) that includes at least one neurosurgeon, ENT, neuroradiologist, neuro-ophthalmologist, endocrine pathologist and endocrinologist specialized in pituitary diseases. We elaborated this guideline with the aim of sharing our experience with other centers involved in the perioperative and surgical management of PT thereby facilitating the management of patients undergoing PS.

How to Classify the Pituitary Neuroendocrine Tumors (PitNET)s in 2020

Adenohypophyseal tumors, which were recently renamed pituitary neuroendocrine tumors (PitNET), are mostly benign, but may present various behaviors: invasive, “aggressive” and malignant with metastases. They are classified into seven morphofunctional types and three lineages: lactotroph, somatotroph and thyrotroph (PIT1 lineage), corticotroph (TPIT lineage) or gonadotroph (SF1 lineage), null cell or immunonegative tumor and plurihormonal tumors. The WHO 2017 classification suggested that subtypes, such as male lactotroph, silent corticotroph and Crooke cell, sparsely granulated somatotroph, and silent plurihormonal PIT1 positive tumors, should be considered as “high risk” tumors. However, the prognostic impact of these subtypes and of each morphologic type remains controversial. In contrast, the French five-tiered classification, taking into account the invasion, the immuno-histochemical (IHC) type, and the proliferative markers (Ki-67 index, mitotic count, p53 positivity), has a prognostic value validated by statistical analysis in 4 independent cohorts. A standardized report for the diagnosis of pituitary tumors, integrating all these parameters, has been proposed by the European Pituitary Pathology Group (EPPG). In 2020, the pituitary pathologist must be considered as a member of the multidisciplinary pituitary team. The pathological diagnosis may help the clinician to adapt the post-operative management, including appropriate follow-up and early recognition and treatment of potentially aggressive forms.

Malignant transformation in non-functioning pituitary adenomas (pituitary carcinoma)

Non-functioning pituitary carcinomas (NFPC) are defined as tumours of adenophyseal origin with craniospinal or systemic dissemination, with the absence of a hormonal hypersecretion syndrome. These are a histologically heterogenous group of tumours, comprising gonadotroph, null cell, "silent" tumours of corticotroph, somatotroph or lactotroph cell lineages as well as plurihormonal Pit-1 tumours. NFPC are exceedingly rare, and hence few cases have been described. This review has identified 38 patients with NFPC reported in the literature. Recurrent invasive non-functioning pituitary adenomas (NFPA) were observed in a majority of patients. Various factors have been identified as markers of the potential for aggressive behaviour, including rapid tumour growth, growth after radiotherapy, gain or shift of hormone secretion and raised proliferative markers. Typically, there is a latency of several years from the original presentation with an NFPA to identification of metastases and only 5 cases reported with rapidly progressive malignant disease within 1 month of presentation. Therapeutic options include debulking surgery, radiation therapy and chemotherapy with temozolomide recommended as first line systemic treatment. Although long-term survivors are described, prognosis remains generally very poor (median survival 8 months). Improvements in molecular tumour profiling may assist in predicting tumour behaviour, guide therapeutic choices and identify novel therapies.

European Society of Endocrinology Clinical Practice Guidelines for the management of aggressive pituitary tumours and carcinomas

BACKGROUND

Pituitary tumours are common and easily treated by surgery or medical treatment in most cases. However, a small subset of pituitary tumours does not respond to standard medical treatment and presents with multiple local recurrences (aggressive pituitary tumours) and in rare occasion with metastases (pituitary carcinoma). The present European Society of Endocrinology (ESE) guideline aims to provide clinical guidance on diagnosis, treatment and follow-up in aggressive pituitary tumours and carcinomas.

METHODS

We decided upfront, while acknowledging that literature on aggressive pituitary tumours and carcinomas is scarce, to systematically review the literature according to the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. The review focused primarily on first- and second-line treatment in aggressive pituitary tumours and carcinomas. We included 14 single-arm cohort studies (total number of patients = 116) most on temozolomide treatment (n = 11 studies, total number of patients = 106). A positive treatment effect was seen in 47% (95% CI: 36-58%) of temozolomide treated. Data from the recently performed ESE survey on aggressive pituitary tumours and carcinomas (165 patients) were also used as backbone for the guideline. SELECTED RECOMMENDATION: (i) Patients with aggressive pituitary tumours should be managed by a multidisciplinary expert team. (ii) Histopathological analyses including pituitary hormones and proliferative markers are needed for correct tumour classification. (iii) Temozolomide monotherapy is the first-line chemotherapy for aggressive pituitary tumours and pituitary carcinomas after failure of standard therapies; treatment evaluation after 3 cycles allows identification of responder and non-responder patients. (iv) In patients responding to first-line temozolomide, we suggest continuing treatment for at least 6 months in total. Furthermore, the guideline offers recommendations for patients who recurred after temozolomide treatment, for those who did not respond to temozolomide and for patients with systemic metastasis.

Outcome of Nonfunctioning Pituitary Adenomas That Regrow After Primary Treatment: A Study From Two Large UK Centers

CONTEXT

Despite the major risk of regrowth of clinically nonfunctioning pituitary adenomas (CNFAs) after primary treatment, systematic data on the probability of further tumor progression and the effectiveness of management approaches are lacking.

OBJECTIVE

To assess the probability of further regrowth(s), predictive factors, and outcomes of management approaches in patients with CNFA diagnosed with adenoma regrowth after primary treatment.

PATIENTS, DESIGN, AND SETTING

Retrospective cohort study of 237 patients with regrown CNFA managed in two UK centers.

RESULTS

Median follow-up was 5.9 years (range, 0.4 to 37.7 years). The 5-year second regrowth rate was 35.3% (36.2% after surgery; 12.5% after radiotherapy; 12.7% after surgery combined with radiotherapy; 63.4% with monitoring). Of those managed with monitoring, 34.8% eventually were offered intervention. Type of management and sex were risk factors for second regrowth. Among those with second adenoma regrowth, the 5-year third regrowth rate was 26.4% (24.4% after surgery; 0% after radiotherapy; 0% after surgery combined with radiotherapy; 48.3% with monitoring). Overall, patients with a CNFA regrowth had a 4.4% probability of a third regrowth at 5 years and a 10.0% probability at 10 years; type of management of the first regrowth was the only risk factor. Malignant transformation was diagnosed in two patients.

CONCLUSIONS

Patients with regrown CNFA after primary treatment continue to carry considerable risk of tumor progression, necessitating long-term follow-up. Management approach to the regrowth was the major factor determining this risk; monitoring had >60% risk of progression at 5 years, and a substantial number of patients ultimately required intervention.

First Report of Coexistence of Two Ectopic Pituitary Tumors: Rathke Cleft Cyst and Silent Adrenocorticotropic Hormone Adenoma

BACKGROUND

Rathke cleft cysts (RCCs) and pituitary adenomas (PAs) are thought to have a common embryonic ancestry; however, PAs with a concomitant RCC inside the sella turcica are rarely observed. Ectopic pituitary tumors are also rare.

CASE DESCRIPTION

We present the case of a 65-year-old woman with an ectopic RCC in the sphenoid sinus and outside the sella turcica concomitant with an adrenocorticotropic hormone (ACTH)-staining, clinically silent PA. The patient had headache but no endocrine or visual disturbances. Preoperative magnetic resonance imaging revealed infrasellar cystic lesion in the sphenoid sinus with erosion of the clivus and intact sellar floor. The patient underwent gross total microsurgical resection through the transnasal route with an uneventful postoperative course.

CONCLUSIONS

To our knowledge, this is the first reported ectopic RCC located outside the sella turcica with a concomitant ACTH-staining PA. This also appears to be the first ACTH-staining adenoma concomitant with RCC reported in the literature, regardless of location, not presenting with Cushing disease. This case shows that we can now include pituitary adenoma with or without a concomitant RCC in the differential diagnosis of processes in the sphenoid sinus. As both PAs and RCCs are benign sellar lesions, surgical management of a concomitant occurrence of these tumors mainly depends on the size of the lesions and their clinical manifestations. For patients with PA and concomitant RCC, surgical resection should be considered, as there is an approximatrely 20% recurrence rate of the cyst after resection and the possibility of future clival erosion, if left untreated.

Pituitary incidentalomas: A guide to assessment, treatment and follow-up

Pituitary incidentalomas are lesions which are detected incidentally in the pituitary gland during imaging procedures for unrelated causes, such as headache, trauma or symptoms involving the neck or central nervous system. The wide application of sensitive brain imaging techniques (CT, MRI) has led to an increasing recognition of such lesions. Although the etiology of pituitary incidentalomas covers a wide range of pathologies, most of them (∼90%) are benign adenomas; nonetheless, they may result in visual and/or neurologic abnormalities. By definition, micro-incidentalomas have maximum diameter of less than 1cm, while macro-incidentalomas are at least 1cm. Micro-incidentalomas have a reported mean prevalence in normal individuals of around 10%. The endocrinologist facing a pituitary incidentaloma has to solve two main diagnostic problems: (i) the nature and extent of the lesion, and (ii) whether hormonal excess or deficits result from the lesion. The former is achieved by the use of pituitary MRI and visual field (VF) examination and the latter by basal or dynamic hormonal assessments. The answers to these two questions will guide the treatment and follow-up. VF deficits or neurological disturbances due to compression of the optic chiasm or nerve by the incidentaloma are the strongest recommendations for surgery. Furthermore, hormonally active incidentalomas, with the exception of prolactinomas, should be treated by surgery. Most cases of pituitary incidentalomas do not meet criteria for surgical excision, but may require follow-up. The follow-up strategy consists of clinical evaluation, pituitary MRI, VF examination and hormonal assessments. Macro-incidentalomas require more extensive initial investigation, as well as closer MRI surveillance, than micro-incidentalomas. Diagnostic, treatment and follow-up strategies should be in alignment with the optimal personalized clinical benefit.

Management of nonfunctioning pituitary incidentaloma

Prevalence of pituitary incidentaloma is variable: between 1.4% and 27% at autopsy, and between 3.7% and 37% on imaging. Pituitary microincidentalomas (serendipitously discovered adenoma <1cm in diameter) may increase in size, but only 5% exceed 10mm. Pituitary macroincidentalomas (serendipitously discovered adenoma>1cm in diameter) show increased size in 20-24% and 34-40% of cases at respectively 4 and 8years' follow-up. Radiologic differential diagnosis requires MRI centered on the pituitary gland. Initial assessment of nonfunctioning (NF) microincidentaloma is firstly clinical, the endocrinologist looking for signs of hypersecretion (signs of hyperprolactinemia, acromegaly or Cushing's syndrome), followed up by systematic prolactin and IGF-1 assay. Initial assessment of NF macroincidentaloma is clinical, the endocrinologist looking for signs of hormonal hypersecretion or hypopituitarism, followed up by hormonal assay to screen for hypersecretion or hormonal deficiency and by ophthalmologic assessment (visual acuity and visual field) if and only if the lesion is near the optic chiasm (OC). NF microincidentaloma of less than 5mm requires no surveillance; those of≥5mm are not operated on but rather monitored on MRI at 6months and then 2years. Macroincidentaloma remote from the OC is monitored on MRI at 1year, with hormonal exploration (for anterior pituitary deficiency), then every 2years. When macroincidentaloma located near the OC is managed by surveillance rather than surgery, MRI is recommended at 6months, with hormonal and visual exploration, then annual MRI and hormonal and visual assessment every 6months. Surgery is indicated in the following cases: evolutive NF microincidentaloma, NF macroincidentaloma associated with hypopituitarism or showing progression, incidentaloma compressing the OC, possible malignancy, non-compliant patient, pregnancy desired in the short-term, or context at risk of apoplexy.

Clinical factors involved in the recurrence of pituitary adenomas after surgical remission: a structured review and meta-analysis

To study the currently available data of recurrence rates of functioning and nonfunctioning pituitary adenomas following surgical cure and to analyze associated predisposing factors, which are not well established. A systematic literature search was conducted using Medline, Embase, Web of Science and the Cochran Library for studies reporting data on recurrence of pituitary adenoma after surgery, in nonfunctioning adenoma (NF), prolactinoma (PRL) acromegaly (ACRO) and Cushing's disease (CUSH). Of 557 initially retrieved potential relevant studies 143 were selected. Recurrence in NFA was defined as reappearance of tumor on MRI or CT. Increase of hormone levels above normal limits as set by the authors after initial remission was used to indicate recurrence in the functioning tumor types. Remission percentage was lowest in NFA compared with other tumor types (P < 0.001). Surgery-related hypopituitarism was more frequent in CUSH than in the other tumors (P < 0.001). Recurrence, expressed as percentage of the cured population or as ratio of recurrence and total patient years of follow-up was highest in PRL (P < 0.001). The remission percentage did not improve over 3 decades of publications, but there was a modest decrease in recurrence rate (P = 0.04). Recurrences peaked between 1 and 5 years after surgery. Most of the studies with a sufficient number of recurrences did not apply multivariate statistics, and mentioned at best associated factors. Age, gender, tumor size and invasion were generally unrelated to recurrence. For functioning adenomas a low postoperative hormone concentration was a prognostically favorable factor. In NFA no specific factor predicted recurrence. Recurrence rate differs between pituitary adenomas, being highest in patients with prolactinoma, with the highest incidence of recurrence between 1 and 5 years after surgery in all adenomas. Patients with NFA have a lower chance of remission than patients with functioning adenomas. The postoperative basal hormone level is the most important predictor for recurrence in functioning adenomas, while in NFA no single convincing factor could be identified.

Pituitary incidentaloma

Pituitary incidentalomas (PIs) are commonly encountered in clinical practice. While most are microincidentalomas (<1 cm) and not functional, in some cases their identification may lead to discovery of unrecognized abnormalities such as pituitary hormonal deficiencies, excess hormone secretion or visual field defects. Although the majority are pituitary adenomas, the potential list of differential diagnosis is extensive. A limited biochemical work up for asymptomatic patients with microincidentalomas, to include measurement of prolactin and IGF-1, is reasonable, with further studies to be tailored based on the clinical picture. All patients with macroincidentalomas (≥1 cm) should be evaluated for hypopituitarism and undergo visual field testing if the sellar mass abuts or compresses the optic chiasm. Most PIs can be followed, closely without surgery over time, but some may require surgical removal, especially if they are found to be macroincidentalomas at presentation, encroaching on or abutting the optic chiasm, or are found to be functional, excluding prolactinomas. Recovery of pituitary function may be seen in some patients with mass effect following resection of a sellar mass. The association of headache and pituitary incidentalomas remains a diagnostic challenge. There are no randomized controlled studies to guide the follow up approach when surgery is not indicated; most of the follow up algorithms in the literature are based on personal experience. Most retrospective series on natural history indicate that microincidentalomas tend not to grow; without a need for long-term follow up unless the patient becomes symptomatic. Macroincidentalomas, on the other hand, have a propensity to grow and need a more aggressive follow up approach to minimize morbidity.

Incidental pituitary adenomas

Object

Pituitary incidentalomas are a common finding with a poorly understood natural history. Over the last few decades, numerous studies have sought to decipher the optimal evaluation and treatment of these lesions. This paper aims to elucidate the current evidence regarding their prevalence, natural history, evaluation, and management.

Methods

A search of articles on PubMed (National Library of Medicine) and reference lists of all relevant articles was conducted to identify all studies pertaining to the incidence, natural history, workup, treatment, and follow-up of incidental pituitary and sellar lesions, nonfunctioning pituitary adenomas, and incidentalomas.

Results

The reported prevalence of pituitary incidentalomas has increased significantly in recent years. A complete history, physical, and endocrinological workup with formal visual field testing in the event of optic apparatus involvement constitutes the basics of the initial evaluation. Although data regarding the natural history of pituitary incidentalomas remain sparse, they seem to suggest that progression to pituitary apoplexy (0.6/100 patient-years), visual field deficits (0.6/100 patient-years), and endocrine dysfunction (0.8/100 patient-years) remains low. In larger lesions, apoplexy risk may be higher.

Conclusions

While the majority of pituitary incidentalomas can be managed conservatively, involvement of the optic apparatus, endocrine dysfunction, ophthalmological symptoms, and progressive increase in size represent the main indications for surgery.

Silent pituitary corticotroph carcinoma in a young dog

An 11-month-old neutered female weimaraner was humanely destroyed 6 days after an acute onset of neurological signs. At necropsy examination the pituitary gland was replaced by a large neoplastic mass that compressed and infiltrated the overlying hypothalamus. Small nodules were detected in the spleen, kidneys and stomach. Adrenal, thyroid and parathyroid glands were normal in size. The primary pituitary mass, visceral nodules and microscopical metastases detected within the ventricles and leptomeninges of the brain comprised polygonal, chromophobic neoplastic cells, which labelled strongly for adrenocorticotrophic hormone (ACTH) on immunohistochemical examination. These findings, in the absence of clinical or pathological evidence of pituitary-dependent hyperadrenocorticism, support a diagnosis of endocrinologically-inactive ('silent') pituitary corticotroph (ACTH-containing) carcinoma.

Pituitary incidentaloma: an endocrine society clinical practice guideline

OBJECTIVE

The aim was to formulate practice guidelines for endocrine evaluation and treatment of pituitary incidentalomas.

CONSENSUS PROCESS

Consensus was guided by systematic reviews of evidence and discussions through a series of conference calls and e-mails and one in-person meeting.

CONCLUSIONS

We recommend that patients with a pituitary incidentaloma undergo a complete history and physical examination, laboratory evaluations screening for hormone hypersecretion and for hypopituitarism, and a visual field examination if the lesion abuts the optic nerves or chiasm. We recommend that patients with incidentalomas not meeting criteria for surgical removal be followed with clinical assessments, neuroimaging (magnetic resonance imaging at 6 months for macroincidentalomas, 1 yr for a microincidentaloma, and thereafter progressively less frequently if unchanged in size), visual field examinations for incidentalomas that abut or compress the optic nerve and chiasm (6 months and yearly), and endocrine testing for macroincidentalomas (6 months and yearly) after the initial evaluations. We recommend that patients with a pituitary incidentaloma be referred for surgery if they have a visual field deficit; signs of compression by the tumor leading to other visual abnormalities, such as ophthalmoplegia, or neurological compromise due to compression by the lesion; a lesion abutting the optic nerves or chiasm; pituitary apoplexy with visual disturbance; or if the incidentaloma is a hypersecreting tumor other than a prolactinoma.

MGMT immunoexpression in silent subtype 3 pituitary adenomas: possible therapeutic implications

The objective of the study was to assess O(6)-methylguanine-DNA methyltransferase (MGMT) immunoreactivity in pituitary adenomas of silent subtype 3 as a potential indicator of temozolomide susceptibility. The Mayo Clinic Anatomic Pathology Database was searched for all cases of silent subtype 3 pituitary adenoma. Each of the 23 cases identified had been confirmed on the basis of histology, immunohistochemical staining for pituitary hormones, as well as on diagnostic ultrastructural criteria. Unstained microscopic sections were immunostained for MGMT and were semiquantitatively assessed. Of the 23 tumors examined, 18 (78%) showed no MGMT immunoreactivity. The remaining five (22%) showed immunoreactivity in < or =50% of tumor cells. Among eight of the most clinically aggressive tumors in this study, six (75%) lacked MGMT immunoreactivity. The observed lack of or low-level expression of MGMT by this distinctive, clinically aggressive form of pituitary adenoma suggests potential efficacy of treatment with the alkylating agent temozolomide.