Hypophysitis Outcome and Factors Predicting Responsiveness to Glucocorticoid Therapy: A Prospective and Double-Arm Study

Unveiling the Etiopathogenic Spectrum of Hypophysitis: A Narrative Review

Hypophysitis, a rare inflammatory disorder of the pituitary gland, has seen an uptick in reported cases in recent years. Our objective is to summarize the most recent research on the etiopathogenesis, molecular mechanisms, and genetics of both primary and secondary hypophysitis. Primary autoimmune hypophysitis (PAH): During the acute phase of the disease, the pituitary gland in enlarged due to the infiltration of T and B lymphocytes. The chronic phase is characterized by progressive and irreversible pituitary atrophy. APA may play a role in the management, diagnosis, and prognosis of PAH. Specific autoantibodies such as anti-GH, anti-PIT-1, and anti-T-PIT have been found in patients with hypophysitis and hypopituitarism. A recent study suggested that a mechanism of escaping clonal deletion and mounting an immune response against self antigens can explain the unusual nature of the immune response observed in PAH patients. A cytokine array shows the presence of gamma-interferon and interleukin-17. Patients carrying mutations in the PIT1 or PROP1 genes may present PAH. Individuals carrying the HLA DQ8 haplotype are four times more likely to develop PAH. Immune checkpoint inhibitors induce hypophysitis (IIHs): IIHs is an increasingly frequent toxicity of in patients on treatment with inhibitors targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death-1 (PD-1). ICIs inhibit the CTLA-4 pathway, leading to overactivation of T lymphocytes. The binding of PD-1/PD-L1 suppresses the activity of T cells, promotes the conversion of T-helpers into T-regulatory cells, and activates pro-survival signaling pathways in cancer cells. Cytokines play a crucial role in IIHs. B-cell infiltration has been observed in IIHs, suggesting that antibody-mediated pituitary injury may contribute. Genetic polymorphisms of CTLA-4 and PD-1 genes can increase the risk of IIHs. HLA alleles may also be involved in the onset of IIHs; this HLA association presents a possible alternative mechanistic hypothesis. IIHs may also be linked to a paraneoplastic syndrome triggered by ectopic expression of pituitary specific antigens. SARS-CoV-2-related hypophysitis: Recently, the literature has reported occurrences of hypophysitis associated with the SARS-CoV-2 virus; long COVID-19 may also present as infundibulo-neuro-hypophysitis. The virus enters the central nervous system because of its distinct interaction with angiotensin-converting enzyme receptors via spike proteins binding the capillary endothelium, and it directly damages the pituitary cells. The effect of SARS-CoV-2 can occur indirectly through inflammation and the release of cytokines. The exact mechanism remains ambiguous. The available data on endocrine complications associated with the SARS-CoV-2 vaccine are scant. Nonetheless, isolated cases of hypophysitis have been documented. Treatment of hypophysitis: Glucocorticoids are the cornerstone in managing primary hypophysitis, given their targeted action on inflammation. A better understanding of the etiopathogenesis and molecular mechanism of hypophysitis can lead to more effective and personalized treatment strategies.

Executive summary of the consensus document on hypophysitis of the Neuroendocrinology Area of Knowledge of the Spanish Society of Endocrinology and Nutrition

The term hypophysitis is used to designate a heterogeneous group of pituitary conditions characterized by the presence of inflammatory infiltration of the adenohypophysis, neurohypophysis, or both. Although hypophysitis are rare disorders, the most common in clinical practice is lymphocytic hypophysitis, a primary hypophysitis characterized by lymphocytic infiltration, which predominantly affects women. Other forms of primary hypophysitis are associated with different autoimmune diseases. Hypophysitis can also be secondary to other disorders such as sellar and parasellar diseases, systemic diseases, paraneoplastic syndromes, infections, and drugs, including immune checkpoint inhibitors. The diagnostic evaluation should always include pituitary function tests and other analytical tests based on the suspected diagnosis. Pituitary magnetic resonance imaging is the investigation of choice for the morphological assessment of hypophysitis. Glucocorticoids are the mainstay of treatment for most symptomatic hypophysitis.

Hypophysitis

OBJECTIVE

Hypophysitis is considered a rare inflammatory disease of the pituitary gland. For a long time, primary autoimmune hypophysitis has stood out as the most relevant type of hypophysitis. However, with the advent of immunotherapy for the treatment of malignancies and identification of hypophysitis as an immune-related adverse event, hypophysitis has garnered increasing interest and recognition. Therefore, awareness, early recognition, and appropriate management are becoming important as the indication for immunomodulatory therapies broaden.

METHODS

In this review, we discuss the epidemiology, diagnosis, and treatment of hypophysitis with a focus on recent data and highlight subtypes of particular interest while recognizing the gaps in knowledge that remain.

RESULTS

Regardless of cause, symptoms and signs of hypophysitis may be related to mass effect (headache and visual disturbance) and hormonal disruption that warrant prompt evaluation. In the vast majority of cases, a diagnosis of hypophysitis can be made presumptively in the appropriate clinical context with radiologic findings consistent with hypophysitis and after the exclusion of other causes.

CONCLUSION

Although subtle differences currently exist in management and outcome expectations between primary and secondary causes of hypophysitis, universally, treatment is aimed at symptom management and hormonal replacement therapy.

Outcomes of Initial Management Strategies in Patients With Autoimmune Lymphocytic Hypophysitis: A Systematic Review and Meta-analysis

CONTEXT

Lymphocytic hypophysitis (LyHy) is characterized by inflammation of the pituitary and or neuroinfundibulum and is uncommon. Treatment options include observation, high-dose glucocorticoids (HD-GCs) or surgery. Optimal first-line management strategy, however, remains unknown.

OBJECTIVE

This work aimed to assess response to first-line treatment options (observation, HD-GCs, or surgery) of clinically relevant outcomes (symptomatic, hormonal, and radiographic improvement) among patients with LyHy.

METHODS

A systematic review was conducted in 6 databases through 2020. Meta-analysis was conducted when feasible using a random-effects model.

RESULTS

We included 33 studies reporting on 591 patients (423 women, 72%) with LyHy. Improvement/resolution of anterior pituitary dysfunction was highest when HD-GCs was first-line treatment. Surgery was associated with the greatest proportion of patients who had regression on imaging. Subgroup analysis comparing HD-GCs to observation showed the odds of anterior pituitary hormone recovery (OR 3.41; 95% CI, 1.68-6.94) or radiographic regression (OR 3.13; 95% CI, 1.54-6.36) were higher with HD-GCs, but so was the need for additional forms of treatment (OR 4.37; 95% CI, 1.70-11.22). No statistically significant difference was seen in recovery of diabetes insipidus (OR 0.9; 95% CI, 0.26-3.10). Certainty in these estimates was very low.

CONCLUSION

Observation and use of HD-GCs both are successful first-line management strategies in LyHy. Although use of HD-GCs was associated with increased recovery of anterior pituitary hormone deficit, it also was associated with greater likelihood of additional treatment after withdrawal. Optimal dosing and duration of HD-GCs remains unknown.

[Clinical and radiological diagnosis of hypophysitis: a review of literature and own data]

This article presents a literature review of the various forms of hypophysitis, its varieties, as well as the problem of radiation diagnosis and treatment of this pathology. Hypophysitis is a poorly understood and multifactorial disease which the difficulty of diagnosing is not only to a variety of nonspecific clinical manifestations and hormonal research data, but also the ambiguous results of MRI studies, the lack of clear MR patterns. The article reflects the main histological types of hypophysitis, the peculiarities of diagnosis in connection with general clinical symptoms, outlines the features of each type of hypophysitis with their own clinical observations. This review is devoted to modern ideas about the clinical course of hypophysitis, presented a set of characteristic diagnostic signs of the disease according to MRI and the treatment algorithms recommended today are also highlighted. The article summarizes data from foreign literature and our own clinical observations in order to develop an optimal protocol for MRI studies in patients with suspected hypophysitis, to develop recommendations for radiologists and endocrinologists for the correct results interpretation. The uniqueness of this review is the lack of data on the clinic, diagnosis and treatment of hypophysitis in the Russian literature today.

Early Pulse Glucocorticoid Therapy and Improved Hormonal Outcomes in Primary Hypophysitis

INTRODUCTION

The role of glucocorticoids in primary autoimmune hypophysitis (PAH) has been fraught with variability in regimens, leading to inconsistent outcomes in terms of anterior pituitary (AP) hormonal recovery. Hence, we aimed to compare the clinical, hormonal, and radiological outcomes of a standardized high-dose glucocorticoid therapy group (GTG) in PAH with a matched clinical observation group (COG).

METHODS

Thirty-nine retrospective patients with PAH evaluated and treated at a single center in western India from 1999 to 2019 with a median follow-up duration of 48 months were subdivided into the GTG (n = 18) and COG (n = 21) and compared for the outcomes.

RESULTS

Baseline demographic, hormonal, and radiological features matched between the groups, except pituitary height, which was significantly higher in GTG. Cortisol, thyroid, and gonadal axes were affected in 25 (64%), 22 (56%), and 21 (54%) patients, respectively, and central diabetes insipidus was seen in 7 (18%) patients. Panhypophysitis (PH) was the most common radiological subtype (n = 33, 84.6%). Resolution of mass effects was similar in both groups. Overall and complete AP hormonal recovery was significantly higher in the GTG than in the COG (12/14 [85.7%) vs. 6/14 [42.8%], p = 0.02; 10/14 [71.4%] vs. 1/14 [7.7%], p = 0.0007, respectively). Proportion of cases with empty sella were significantly higher in the COG (9/20 [45%] vs 1/17 [5.9%], p = 0.001). Among PH patients in the GTG (n = 17), we found duration from symptoms onset to treatment as the predictor of recovery.

CONCLUSION

In a PH subtype-predominant PAH cohort, a standardized high-dose glucocorticoid regimen resulted in higher overall and complete AP hormonal recovery than that in the COG. Initiation of glucocorticoids in the early disease course may have been contributory.

Hypophysitis, the Growing Spectrum of a Rare Pituitary Disease

Hypophysitis is defined as inflammation of the pituitary gland that is primary or secondary to a local or systemic process. Differential diagnosis is broad (including primary tumors, metastases, and lympho-proliferative diseases) and multifaceted. Patients with hypophysitis typically present with headaches, some degree of anterior and/or posterior pituitary dysfunction, and enlargement of pituitary gland and/or stalk, as determined by imaging. Most hypophysitis causes are autoimmune, but other etiologies include inflammation secondary to sellar tumors or cysts, systemic diseases, and infection or drug-induced causes. Novel pathologies such as immunoglobulin G4-related hypophysitis, immunotherapy-induced hypophysitis, and paraneoplastic pituitary-directed autoimmunity are also included in a growing spectrum of this rare pituitary disease. Typical magnetic resonance imaging reveals stalk thickening and homogenous enlargement of the pituitary gland; however, imaging is not always specific. Diagnosis can be challenging, and ultimately, only a pituitary biopsy can confirm hypophysitis type and rule out other etiologies. A presumptive diagnosis can be made often without biopsy. Detailed history and clinical examination are essential, notably for signs of underlying etiology with systemic manifestations. Hormone replacement and, in selected cases, careful observation is advised with imaging follow-up. High-dose glucocorticoids are initiated mainly to help reduce mass effect. A response may be observed in all auto-immune etiologies, as well as in lymphoproliferative diseases, and, as such, should not be used for differential diagnosis. Surgery may be necessary in some cases to relieve mass effect and allow a definite diagnosis. Immunosuppressive therapy and radiation are sometimes also necessary in resistant cases.

Hypophysitis: A comprehensive overview

Hypophysitis is defined as inflammation of the pituitary gland. It is a heterogeneous condition as it can originate from different parts of the pituitary gland, can be caused by different pathophysiological processes, and can be isolated or the manifestation of a underlying systemic disease. Hypophysitis usually presents with endocrine deficiencies, including diabetes insipidus, with varying patterns. A subset of patients presents with mass effects. The last decades major progress has been made in the understanding of this disease. New forms are now recognized, new diagnostics are being developed, and specific treatments are proposed. This review provides an overview of the current knowledge on hypophysitis using an aetiology-based approach and provides the clinician with a stepwise approach to the patient with (suspected) hypophysitis.

Molecular and Genetic Immune Biomarkers of Primary and Immune-Therapy Induced Hypophysitis: From Laboratories to the Clinical Practice

Hypophysitis is a rare and potentially life-threatening disease, characterized by an elevated risk of complications, such as the occurrence of acute central hypoadrenalism, persistent hypopituitarism, or the extension of the inflammatory process to the neighboring neurological structures. In recent years, a large number of cases has been described. The diagnosis of hypophysitis is complex because it is based on clinical and radiological criteria. Due to this, the integration of molecular and genetic biomarkers can help physicians in the diagnosis of hypophysitis and play a role in predicting disease outcome. In this paper, we review current knowledge about molecular and genetic biomarkers of hypophysitis with the aim of suggesting a possible integration of these biomarkers in clinical practice.

Markers of humoral and cell-mediated immune response in primary autoimmune hypophysitis: a pilot study

INTRODUCTION

Primary autoimmune hypophysitis (PAHs) is a rare inflammatory disease of the pituitary gland. Although largely investigated, the pathogenesis of PAH is not completely clarified. We aimed to investigate the immune response in PAHs.

MATERIAL AND METHODS

Serum anti-pituitary and anti-hypothalamus antibodies (respectively APAs and AHAs) were investigated though an indirect immunofluorescence on monkey hypophysis and hypothalamus slides, serum cytokines though an array membrane and cell-mediated immunity though the white blood cells count.

RESULTS

Nineteen PAH cases entered the study. APA or AHA were identified in all cases. APA were detected in 13 patients (68.4%) and AHA in 13 patients (68.4%). Ten patients (52.6%) were simultaneously positive for both APA and AHA. The prevalence of APAs and AHAs was higher as compared to those observed in 50 health controls (respectively 14% p < 0.001 and 24% p = 0.004) and in 100 not-secreting pituitary adenoma (NFPAs) (respectively 22% p = 0.002 and 8% p < 0.001). Similarly, the prevalence of simultaneous positivity for APA and AHA (52.9%) was higher as compared to the those detected in patients affected by NFPAs (0%; p < 0.001) and in health controls (16% p = 0.002). No differences were identified between PAHs and controls at qualitative and quantitative analysis of serum cytokines and white blood cells count.

CONCLUSIONS

This study suggest that APA and AHA may be detected in an high percentage of PAH cases and that their simultaneous identification may be useful for the differential diagnosis between PAH and NFPAs, in an appropriate clinical context.

Diabetes insipidus secondary to sellar/parasellar lesions

Diabetes insipidus (DI) is a well-recognised transient or permanent complication following transsphenoidal surgery for pituitary adenomas or other sellar/parasellar lesions. However, data regarding the prevalence of pre-operative DI in sellar/parasellar lesions other than pituitary adenomas are scarce. We systematically reviewed the existing data for defining the prevalence of DI before any treatment in adult patients with sellar/parasellar lesions, excluding pituitary adenomas and metastatic lesions. In total, 646 patients with sellar/parasellar lesions presenting with DI at diagnosis were identified. The most common pathologies of sellar/parasellar lesions presenting with DI at diagnosis were lymphocytic hypophysitis (26.5%), craniopharyngiomas (23.4%), Langerhans's cell histiocytosis (18.9%) and Rathke's cleft cyst (12.7%), accounting for the vast majority (more than 80%) of these lesions. Overall, DI at diagnosis was found in 23.4% of all patients with sellar/parasellar lesions, albeit with a wide range from 10.6% to 76.7%, depending on the nature of the pathology. The highest prevalence of DI was found in less commonly encountered lesions namely germ-cell tumours (76.7%), abscesses (55.4%) and neurosarcoidosis (54.5%), each accounting for less than 3% of all sellar/parasellar lesions. Most DI cases (68.8%) were associated with anterior pituitary hormonal deficiencies, in contrast to pituitary adenomas that rarely present with DI. The enlargement and enhancement of the pituitary stalk were the most common findings on magnetic resonance imaging besides the loss of the high signal of the posterior pituitary on T1-weighted images. Resolution of DI spontaneously or following systemic and surgical management occurred in 22.4% of cases. Post-operative DI, not evident before surgery, was found in 27.8% of non-adenomatous sellar/parasellar lesions, and was transient in 11.6% of them. Besides distinctive imaging features and symptoms, early recognition of DI in such lesions is important because it directs the diagnosis towards a non-adenomatous sellar/parasellar tumour and the early initiation of appropriate treatment.

Hypothalamitis and pituitary atrophy

Hypothalamitis is a rare inflammatory disorder involving the hypothalamus and classified as primary, or isolated, and secondary hypothalamitis. Secondary hypothalamitis although very rare is more common than the primary one and may occur in patients affected by autoimmune diseases such as autoimmune hypophysitis, systemic autoimmune diseases, infective diseases in patients affected by immune-deficit, paraneoplastic encephalitis, or in patients treated with immune checkpoint inhibitors. In accordance with the rarity of this disease, diagnosis and management of hypothalamitis prove to be challenging. The diagnosis requires a high index of clinical suspicion. The main symptoms may be: various degrees of hypopituitarism, neuropsychiatric and behavioral disorders, and disturbances of autonomic and metabolic regulation. Magnetic resonance images play a crucial role in the diagnosis of hypothalamitis and in the exclusion of a neoplastic lesion. Therapeutic management should be oriented according to the disease etiology. In most cases, after ruling out infective hypothalamitis, the mainstay of therapy consists of immunosuppressive treatment. Great attention should be paid to hormonal replacement therapy, if partial or total hypopituitarism is present, in particular in patients affected by diabetes insipidus, central hypoadrenalism and hypothyroidism. According to the complexity of this disease, a multidisciplinary approach is strongly advocated to reach an early diagnosis and an integrated therapy.

Empty sella syndrome: Multiple endocrine disorders

Empty sella is a pituitary disorder characterized by the herniation of the subarachnoid space within the sella turcica. This is often associated with a variable degree of flattening of the pituitary gland. Empty sella has to be distinguished in primary and secondary forms. Primary empty sella (PES) excludes any history of previous pituitary pathologies such as previous surgical, pharmacologic, or radiotherapy treatment of the sellar region. PES is considered an idiopathic disease and may be associated with idiopathic intracranial hypertension. Secondary empty sella, however, may occur after the treatment of pituitary tumors through neurosurgery or drugs or radiotherapy, after spontaneous necrosis (ischemia or hemorrhage) of chiefly adenomas, after pituitary infectious processes, pituitary autoimmune diseases, or brain trauma. Empty sella, in the majority of cases, is only a neuroradiological finding, without any clinical implication. However, empty sella syndrome is defined in the presence of pituitary hormonal dysfunction (more frequently hypopituitarism) and/or neurological symptoms due to the possible coexisting of idiopathic intracranial hypertension. Empty sella syndrome represents a peculiar clinical entity, characterized by heterogeneity both in clinical manifestations and in hormonal alterations, sometimes reaching severe extremes. For a proper diagnosis, management, and follow-up of empty sella syndrome, a multidisciplinary approach with the integration of endocrine, neurological, and ophthalmological experts is strongly advocated.

Primary and Ipilimumab-induced Hypophysitis: A Single-center Case Series

PURPOSE

To present a case series of primary and immunotherapy-related secondary hypophysitis.

METHODS

A single-center retrospective chart review was performed at the University of British Columbia, Vancouver, Canada. Eleven cases of primary hypophysitis and 2 cases of immunotherapy-related secondary hypophysitis were included. Of the 11 primary cases, 6 were diagnosed clinically without biopsy.

RESULTS

In primary hypophysitis, headache was the most common presenting symptom (6/11; 55%) and stalk enlargement the prevailing radiologic sign (8/11; 73%). Central adrenal insufficiency (4/11; 36%), central hypothyroidism (4/11; 36%), and central diabetes insipidus (CDI) (4/11; 36%) were the most common pituitary deficiencies at presentation. Initial management included surgery (4/11; 36%), supraphysiologic steroids (2/11; 18%), or observation (6/11; 55%). Outcomes assessed included radiologic improvement (8/9; 89%), improvement in mass symptoms (4/7; 57%), anterior pituitary recovery (1/7; 14%), and CDI recovery (0/4; 0%). In immunotherapy-related hypophysitis either under observation or supraphysiologic steroid therapy, the inflammatory mass resolved and pituitary dysfunction persisted.

CONCLUSIONS

In primary hypophysitis, the inflammatory pituitary mass typically resolves and hypopituitarism persists. In the absence of severe or progressive neurologic deficits, a presumptive clinical diagnosis and conservative medical management should be attempted. In the absence of severe features, immunotherapy-related hypophysitis may be managed effectively without the use of supraphysiologic steroids.

Granulomatous hypophysitis causing compression of the internal carotid arteries reversible with azathioprine and rituximab treatment

INTRODUCTION

Compression of the internal carotid artery (ICA) in the cavernous sinus area is a rare event and is mostly associated with pituitary adenomas and meningiomas. Other causes of ICA compression are less well known. We present a rare case of granulomatous hypophysitis causing compression of the ICA, which was treated successfully with immune-suppressive agents.

METHODS

The electronic database MEDLINE (PubMed) was searched systematically and other cases with ICA compression were identified and analyzed.

RESULTS

A female patient with a history of two previous transsphenoidal operations for suspected pituitary adenoma and post-operative complete pituitary insufficiency presented with severe headaches, nausea, fatigue, and diplopia. Pituitary MRI scan suggested relapse of the pituitary lesion with atypical bilateral infiltration of cavernous sinuses and compression of ICAs. After histological reevaluation of her previous pituitary operations, granulomatous hypophysitis was diagnosed. Treatment was started with high doses of prednisolone. With decreasing doses of prednisolone, symptoms recurred, and azathioprine was started, followed by administration of rituximab resulting in clinical recovery and regression of ICA compression. Literature analysis disclosed 36 case reports with ICA compression in the cavernous sinus region (12 pituitary adenoma, 6 meningioma, 7 hypophysitis, 5 other tumors, and 4 other etiologies). Two cases of hypophysitis recovered completely; five cases improved only partly.

CONCLUSION

In the case of ICA compression, clinical signs, onset of symptoms, radiological findings and pituitary insufficiencies should be thoroughly evaluated, and hypophysitis should be considered as a possible cause. In our patient, treatment with azathioprine and, finally, rituximab was successful.

Hypophysitis (Including IgG4 and Immunotherapy)

Hypophysitis is characterized by inflammation of the pituitary gland that can be primary (PH) or secondary (SH) to other diseases or following drug administration. It may also be classified according to anatomical and histopathological criteria, leading to variable degrees of hypopituitarism and/or compressive symptoms to nearby structures. There has recently been an increase in the number of hypophysitis cases, raising the interest on the spectrum of its pathogenesis, clinical, biochemical/endocrinological, and imaging features. However, the use of conventional biomarkers, including currently utilized pituitary autoantibodies, has relatively limited diagnostic accuracy. Lymphocytic hypophysitis (LH) is the commonest cause of PH, whereas IgG4-related hypophysitis is increasingly being recognized. Histiocytosis and granulomatous diseases are the most frequent causes of SH, although infections and lymphoma have also been reported. The increasing use of immune checkpoint inhibitors in oncology is associated with a high incidence of hypophysitis, providing further understanding of its pathogenesis. Hypophysitis can occur silently and be easily missed, potentially leading to substantial morbidity or mortality due to adrenal insufficiency, requiring a high index of clinical suspicion and timely initiation of appropriate treatment. In most cases of LH or drug-induced hypophysitis, active surveillance along with replacement of established hormonal deficiencies is needed. In the presence of compressive and/or evolving symptoms, treatment with glucocorticoids either alone or in combination with other immunosuppressive agents can be used. Surgical decompression is reserved for nonresponsive cases with threatened vital structures. Timely diagnosis and intervention are important to minimize disease-related morbidity and mortality. We aimed to review current concepts and recent developments in the pathogenesis, diagnosis, and management of hypophysitis.

Hypophysitis: An update on the novel forms, diagnosis and management of disorders of pituitary inflammation

Hypophysitis is a heterogeneous condition that leads to inflammation of the sella and/or suprasellar region, potentially resulting in hormonal deficiencies and/or mass effects. A preponderance of hypophysitis subtypes have an underlying autoimmune aetiology. The overall incidence and prevalence of hypophysitis has dramatically increased over the past decade, mainly due to increased awareness of the condition in the medical community, improvements in imaging techniques, and a rise in the occurrence of certain forms of hypophysitis such as IgG4 hypophysitis (IgG4Hy) and immune checkpoint inhibitor induced hypophysitis (ICIHy). The clinical presentation varies from an asymptomatic condition to a fatal disease often as a result of electrolyte abnormalities due to glucocorticoid deficiency in the context of adrenal crisis from central adrenal insufficiency. Milder forms of hypophysitis are treated with replacement of deficient hormones while more acute presentations with mass effects require glucocorticoid therapy, immunosuppressive therapy or surgery. Timely diagnosis and interventions are keys to prevention of the lethal complications of this disease. In this review, we provide an update on the recent advances in the field of pituitary autoimmunity, with an emphasis on autoimmune hypophysitis and novel forms of hypophysitis such as anti-PIT1 hypophysitis, IgG4Hy and ICIHy.

The Changing Clinical Spectrum of Hypophysitis

Hypophysitis is a rare and potentially life-threatening disease, characterized by an elevated risk of complications, such as occurrence of acute central hypoadrenalism, persistent hypopituitarism, or extension of the inflammatory process to the neighboring neurological structures. In recent years, a large number of patients have been described as being affected by hypophysitis, due to the increased administration of immuno-chemotherapies. At the present time, the heterogeneous nature of hypophysitis diagnostic criteria and of the treatment protocols makes the management of affected patients difficult. We review the current data and evidence on primary and secondary hypophysitis, in order to suggest a diagnostic and therapeutic protocol that should be focused on a multidisciplinary approach, for reaching a prompt diagnosis and an appropriate and safe treatment.

Hypophysitis in the era of immune checkpoint inhibitors and immunoglobulin G4-related disease

INTRODUCTION

Hypophysitis is a rare disorder, defined as inflammation of the pituitary gland that may result in pituitary enlargement and varying anterior and posterior pituitary hormonal deficits. It involves different histopathological subtypes and variable etiologies, with considerable overlap between classification systems. Histopathology is the gold standard diagnostic approach.

AREAS COVERED

In this article, we will review the major histopathological subtypes of hypophysitis with a special focus on immunoglobulin G4 (IgG4)-related hypophysitis and immune checkpoint inhibitor-induced hypophysitis, given their recent appearance and increasing incidence. We will summarize the similarities and differences between the different subtypes as it relates to epidemiology, pathogenesis, presentation, diagnosis, and management.

EXPERT OPINION

Hypophysitis is a heterogeneous and wide term used to describe different, possibly distinct diseases often with poorly understood pathogenesis. It involves a wide range of subtypes with certain differences in incidence rates, pathogenesis, and management. Management usually focuses on relieving the mass effect symptoms and replacing the deficient pituitary hormones. Spontaneous recovery is possible but recurrence is not uncommon.