From Japan with love: another tessera in the hypophysitis mosaic

Type 3 autoimmune polyglandular syndrome (APS-3) or type 3 multiple autoimmune syndrome (MAS-3): an expanding galaxy

BACKGROUND

The number of recognised distinct autoimmune diseases (AIDs) has progressively increased over the years with more than 100 being reported today. The natural history of AIDs is characterized by progression from latent and subclinical to clinical stages and is associated with the presence of the specific circulating autoantibodies. Once presented, AIDs are generally chronic conditions. AIDs have the tendency to cluster and co-occur in a single patient. Autoimmune thyroid diseases (AITD) are the most prevalent of AIDs in the world population, and about one-third of the AITD patients also present with a non-thyroid AID during their life-span. Furthermore, patient with non-thyroid AIDs often presents with a form of AITD as a concurrent condition. Many of the clusters of AIDs are well characterized as distinctive syndromes, while some are infrequent and only described in case reports.

PURPOSE

In this review, we describe the wide spectrum of the combinations and the intricate relationships between AITD and the other AIDs, excluding Addison's disease. These combinations are collectively termed type 3 Autoimmune Polyglandular Syndrome (APS-3), also called type 3 Multiple Autoimmune Syndrome (MAS-3), and represent the most frequent APS in the world populations.

CONCLUSIONS

Numerous associations of AITD with various AIDs could be viewed as if the other AIDs were gravitating like satellites around AITD located in the center of a progressively expanding galaxy of autoimmunity.

Central diabetes insipidus with anti-rabphilin-3A antibody positivity causing hypovolemic shock after resection of tumorous lesions in the pelvic cavity

A 36-year-old female was pointed out to have liver enzyme elevation by routine health checkup. Subsequent contrast-enhanced CT scan identified gigantic uterine fibroids and retroperitoneal tumor. She was referred to the gynecologist at JA Toride Medical Center and planned to undergo a uterus enucleation and biopsy of the retroperitoneal tumor. The surgery was conducted without any troubles. After the surgery, the patient presented polyuria with urine volume 10-20 L a day and developed hypovolemic shock. Laboratory test revealed hypotonic urine and hypernatremia. Arginine vasopressin (AVP) loading test suggested shortage of endogenous vasopressin. Since the subcutaneous administration of AVP was not sufficient to control the urine volume, continuous intravenous infusion of AVP was initiated. After achieving hemodynamic stability, the treatment was switched to oral desmopressin. MRI finding indicated attenuation of high signal in posterior pituitary in T1 weighted image while neither enlargement of pituitary nor thickening of pituitary stalk was indicated by enhanced MRI. Hypertonic salt solution test indicated no responsive elevation of AVP, confirming the diagnosis of central diabetes insipidus (CDI). Her anterior pituitary function was preserved. Only anti-rabphilin-3A antibody was found positive in the serum of the patient, while other secondary causes for CDI were denied serologically and radiologically. Hence, lymphocytic infundibuloneurohypophysitis　(LINH) was suspected as the final diagnosis. Hormonal replacement therapy by nasal desmopressin was continued and the patient managed to control her urine volume. In cases of CDI considered idiopathic with conventional examinations, anti-rabphilin-3A antibody may be a clue for determining the cause as LINH.

Ketoacidosis, Hypertriglyceridemia and Acute Pancreatitis Induced by Soft Drink Polydipsia in a Patient with Occult Central Diabetes Insipidus

A 21-year-old Japanese man without known diabetes mellitus had abdominal pain. The diagnosis was ketoacidosis and hypertriglyceridemia-induced acute pancreatitis. He had polydipsia and polyuria and had habitually drunk several soft drinks every day for two years. After hospitalization, despite adequate liquid intake, dehydration remained with hypotonic polyuria. Further examinations revealed the coexistence of central diabetes insipidus (CDI), possibly caused by lymphocytic infundibulo-neurohypophysitis, based on anti-rabphilin-3A antibody positivity. Although CDI had been undiagnosed for two years, over-consumption of sugar-rich soft drinks to ease thirst caused ketoacidosis, hypertriglyceridemia, and acute pancreatitis. There are no previous reports of this three-part combination of symptoms caused by CDI.

Recent insights into the pathogenesis of autoimmune hypophysitis

INTRODUCTION

Hypophysitis is an inflammation of the pituitary gland and a rare case of hypopituitarism. Despite the expanding spectrum of histological variants and causative agents, its pathogenesis is far to be fully understood. The present review is focused on recent evidence concerning the pathogenesis of autoimmune hypophysitis by searching through online databases like MEDLINE and Scopus up to May 2021.

AREAS COVERED

Hypophysitis frequently develops in the context of a strong autoimmune background, including a wide spectrum of subtypes ranging from the commonest form of lymphocytic hypophysitis to the newly described and less common IgG4-, anti-PIT-1, and ICI-induced forms. A peculiar combination of genetic predisposition, pituitary damage and immunological setting represents the pathogenetic basis of autoimmune hypophysitis, which is characterized by diffuse infiltration of the gland by lymphocytes and variable degrees of fibrosis followed by pituitary cell destruction. Anti-pituitary antibodies (APA) have been described in sera from patients suffering from autoimmune hypophysitis, though their pathophysiological significance remains largely unknown and their diagnostic value limited.

EXPERT OPINION

In recent years hypophysitis has gained interest due to the increased number of new diagnoses and the recognition of novel subtypes. Further studies could lead to improvements in biochemical/immunological diagnosis and targeted treatments.

Clinical presentation and management of hypophysitis: An observational study of case series

Background:

Hypophysitis is described as a rare chronic inflammatory affection of the pituitary gland. However, to date, its pathogenesis has not been completely cleared up. Clinical features are polymorphic, including symptoms related to inflammatory compression and/or hypopituitarism. Laboratory tests determine hormone deficiencies orientating replacement therapy’s protocol. MRI of the hypothalamic-pituitary region is crucial in exhibiting major radiological signs such as pituitary homogeneous enlargement and gland stalk’s thickening. The etiological diagnosis is still challenging without affecting the management strategy. Corticosteroids have widely been used but a close follow-up without any treatment has also been approved.

Case Description:

In this report, seven patients with hypophysitis have been collected over a period of 6 years. The average age of our patients was 32.1 years ± 11.8 with a female predominance (71.4%). Panhypopituitarism was objective in 42.9% of cases, a combined deficiency of the hypothalamic-pituitary thyroid, adrenal and gonadal axes in 28.6% of cases. A central diabetes insipidus was noted in 42.9% of the patients. Idiopathic hypophysitis was the most common etiology. The use of long course corticosteroids was required in 28.6% when compressive signs were reported.

Conclusion:

Hypophysitis remains a rare disease with nonspecific clinical and radiological patterns. Autoimmune origin seems to be the most frequent etiology. No guidelines have been established for hypophysitis management and the evolution is still unpredictable.

IgG4-related hypophysitis

Hypophysitis is a rare pituitary inflammatory disorder classified in different ways. Immunoglobulin G4-related disease (IgG4-RD), also a rare disease is a systemic fibro-inflammatory condition characterized by infiltration of tissue with IgG4-positive plasma cells; however prevalence of both of them probably is underestimated. In this paper, we present an Iranian patient with biopsy-proven IgG4-related hypophysitis and then review the clinical characteristics, laboratory, imaging, pathologic findings and therapeutic management as well as prognosis of 115 published cases of hypophysitis secondary to IgG4-related disease.

The neurology of IGG4-related disease

PURPOSE OF REVIEW

IgG4-related disease (IgG4-RD) is emerging as a fibro-inflammatory entity affecting multiple organs, including manifold neurologic manifestations. This review discusses general characteristics of IgG4-RD neurologic disease including epidemiology, histology, clinical picture and treatment approaches.

RECENT FINDINGS

IgG4-RD is increasingly recognized as an important underlying pathophysiology in multiple disorders of neurologic interest, including orbital inflammation, infundibulo-hypophysitis, hypertrophic pachymeningitis, and even in rare cases CNS parenchymal disease and cranial vascular involvement. These were previously considered idiopathic and unrelated to any systemic disease but now known to share a common histopathology. New knowledge regarding the pathogenesis, clinical features and epidemiology of IgG4 is emerging, and new neurological manifestations continue to be described. Diagnostic progress includes CT-PET imaging, the use of flow cytometry for plasmablast quantification, and the use of reverse passive latex agglutination aiming to overcome the prozone phenomenon. Histopathologic confirmation of IgG4-RD remains the gold standard method of diagnosis but new diagnostic criteria for systemic and organ-specific disease are being proposed. Though glucorticoids remain the mainstay of therapy, relapses and incomplete recovery are frequent. Rituximab is a promising treatment in IgG4-RD that is severe, refractory or glucocorticoid dependent. Initiation of immunosuppression at an early stage of disease should be considered in order to avoid development of refractory fibrosis.

SUMMARY

The current review emphasizes the neurologic manifestations of IgG4-RD.

Anti-pituitary antibodies as a marker of autoimmunity in pituitary glands

Autoimmunity contributes to the pathogenesis of hypophysitis, a chronic inflammatory disease in the pituitary gland. Although primary hypophysitis is rare, the number of pituitary dysfunction cases induced by immune checkpoint inhibitors (ICIs) is increasing. While it is difficult to prove the involvement of autoimmunity in the pituitary glands, circulating anti-pituitary antibodies (APAs) can be measured by indirect immunofluorescence and used as a surrogate marker of pituitary autoimmunity. APAs are present in several pituitary diseases, including lymphocytic adenohypophysitis, lymphocytic infundibulo-neurohypophysitis (LINH), IgG4-related hypophysitis, and pituitary dysfunction induced by ICIs. Mass spectrometry analysis of antigens targeted by APAs clarified rabphilin-3A as an autoantigen in LINH. This demonstrates that APAs can be applied as a probe to identify novel autoantigens in other pituitary autoimmune diseases, including pituitary dysfunction induced by ICIs, which can aid in biomarker discovery.

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.

Clinical and hormonal characteristics of patients with different types of hypophysitis: a single-center experience

OBJECTIVE

The inflammation of the pituitary gland is known as hypophysitis. It is a rare disease accounting for approximately 0.24%-0.88% of all pituitary diseases. The natural course of hypophysitis is variable. Main forms are histologically classified as lymphocytic, granulomatous, IgG4 related and xanthomatous. We aim to present our patients with hypophysitis and compare clinical, laboratory and radiological features.

SUBJECTS AND METHODS

We retrospectively reviewed our database of 1.293 patients diagnosed with pituitary diseases between 2010 and 2017. Twelve patients with hypophysitis were identified. Demographical data, clinical features, endocrinological dysfunction, imaging findings, treatment courses and follow-up periods were evaluated.

RESULTS

The frequency of hypophysitis was found 0.93% in all cases of the pituitary disease. Twelve patients (nine females and three males), ages between 17-61 years, were evaluated. The characteristic features of our patients tended to be predominantly female and young. Diagnosis of hypophysitis was made after pituitary biopsy in four patients, and in eight patients after pituitary operation due to adenoma. Headache (67%) and visual problems (33%) were the most frequent nonendocrine symptoms. Anterior pituitary hormone deficiencies (63.7%) and/or diabetes insipidus (17%) were seen among patients. According to histopathological forms, four had lymphocytic, seven had granulomatous and one had xanthogranulomatous types. Contrast enhancement heterogeneous and thickened pituitary stalk were the most common radiological alterations.

CONCLUSION

Hypophysitis should be considered in the differential diagnosis of sellar masses. It can mimic pituitary adenomas in radiological and endocrinological aspects. The different patterns of pituitary hormone deficiencies may be seen in the course of the disease.

Rituximab treatment for isolated IgG4-related hypophysitis in a teenage female

IgG4-related hypophysitis is an important diagnostic consideration in patients with a pituitary mass or pituitary dysfunction and can initially present with headaches, visual field deficits and/or endocrine dysfunction. Isolated IgG4-related pituitary disease is rare, with most cases of IgG4-related disease involving additional organ systems. We report the case of a teenage female patient with isolated IgG4-related hypophysitis, diagnosed after initially presenting with headaches. Our patient had no presenting endocrinologic abnormalities. She was treated with surgical resection, prednisolone and rituximab with no further progression of disease and sustained normal endocrine function. This case, the youngest described patient with isolated IgG4-related hypophysitis and uniquely lacking endocrinologic abnormalities, adds to the limited reports of isolated pituitary disease. The use of rituximab for isolated pituitary disease has never been described. While IgG4-related hypophysitis has been increasingly recognized, substantial evidence concerning the appropriate treatment and follow-up of these patients is largely lacking. Learning points: IgG4-related hypophysitis most often occurs in the setting of additional organ involvement but can be an isolated finding. This diagnosis should therefore be considered in a patient presenting with pituitary abnormalities. Most patients with IgG4-related hypophysitis will have abnormal pituitary function, but normal functioning does not exclude this diagnosis. Corticosteroids have been the mainstay of therapy for IgG4-related disease, with other immunosuppressive regimens being reserved for refractory cases. Further research is needed to understand the effectiveness of corticosteroid-sparing regimens and whether there is utility in using these agents as first-line therapies.

Neuro-radiological features can predict hypopituitarism in primary autoimmune hypophysitis

Primary autoimmune hypophysitis (PAH) is considered an underdiagnosed disease, due to the difficulty in reaching a definitive diagnosis. PAH clinical diagnosis remains an exclusion diagnosis. We aimed to correlate PAH neuro-radiological signs to endocrine features and evaluate their prognostic role. 24 PAH cases were enrolled and classified according to neuro-radiological signs: in 12 adeno-hypophysitis (AHs), 8 infundibulo-neuro-hypophysitis (INHs) and 4 pan-hypophysitis (PHs). Secondary hypogonadism developed more frequently in INHs as compared to AHs (54.5% vs. 27.3%, p = 0.05), without no difference with PHs (p = 0.6). Diabetes insipidus occurred more frequently in INHs cases (72.7%, p < 0.001) and in PHs cases (27.3%, p = 0.007), as compared to AHs cases (0%). Similarly, all cases of GHD occurred in INHs (100%) as compared to AHs (0%, p < 0.001) and PHs (0%, p < 0.001). The pituitary stalk (PS) showed a pseudo-triangular shape (larger at the optical chiasma) in INHs and a pseudo-cylindrical shape (larger both at the optical chiasma and at the pituitary insertion) in PHs. The PS pseudo-triangular shape correlated to the occurrence of GHD and diabetes insipidus (p < 0.001/p = 0.03). At the 1-year follow-up, improvement of baseline radiological features positively correlated with the loss of the neuro-pituitary "bright spot" on T1-weighted images (OR 0.16; 95% CI 0.03-0.9 p = 0.02) and with a PS diameter at the optical chiasma level larger than 4.1 mm (AUC 0.97, sensibility 80%, specificity 100%, OR 6; 95% CI1.1-28.8, p = 0.01) Our data suggest that neuro-radiological PAH classification in PH, AH and INH can predict pituitary dysfunction and that some neuro-radiological features, such as the pituitary stalk diameter and the loss of the neuro-pituitary bright spot on T1w images can play a role as a positive prognostic marker of the radiological hypophysitis outcome.

Subacute Hypophysitis with Panhypopituitarism as First Presentation of HIV and Syphilis Coinfection

Infection by Treponema pallidum still represents a clinical challenge due to its various forms of presentation. HIV coinfection added diversity and changed the natural history of syphilis as a systemic infection. We present a rare case of subacute hypophysitis and panhypopituitarism due to an early active neurosyphilis in a previously unknown HIV coinfected patient.

Anti-pituitary antibodies against corticotrophs in IgG4-related hypophysitis

PURPOSE

IgG4-related disease is a systemic inflammatory disease characterized by infiltration of IgG4-positive plasma cells into multiple organs, including the pituitary gland. Autoimmunity is thought to be involved in the pathogenesis of IgG4-related disease. The diagnosis of IgG4-related hypophysitis (IgG4-RH) is difficult because its clinical features, such as pituitary swelling and hypopituitarism, are similar to those of other pituitary diseases, including lymphocytic hypophysitis and sellar/suprasellar tumors. The presence and significance of anti-pituitary antibodies (APA) in IgG4-RH is unclear.

METHODS

In this case-control study, we used single indirect immunofluorescence on human pituitary substrates to assess the prevalence of serum APA in 17 patients with IgG4-RH, 8 control patients with other pituitary diseases (lymphocytic infundibulo-neurohypophysitis, 3; craniopharyngioma, 2; germinoma, 3), and 9 healthy subjects. We further analyzed the endocrine cells targeted by the antibodies using double indirect immunofluorescence.

RESULTS

APA were found in 5 of 17 patients with IgG4-RH (29%), and in none of the pituitary controls or healthy subjects. The endocrine cells targeted by the antibodies in the 5 IgG4-RH cases were exclusively corticotrophs. Antibodies were of the IgG1 subclass, rather than IgG4, in all 5 cases, suggesting that IgG4 is not directly involved in the pathogenesis. Finally, antibodies recognized pro-opiomelanocortin in 2 of the cases.

CONCLUSIONS

Our study suggests that autoimmunity is involved in the pathogenesis of IgG4-RH and that corticotrophs are the main antigenic target, highlighting a possible new diagnostic marker for this condition.

Critical review of IgG4-related hypophysitis

PURPOSE

IgG4-related hypophysitis is a rare disease, with only 34 cases published in English (2015). Available short reviews may not present complete details of IgG4-related hypophysitis. We aimed to survey case reports of IgG4-related hypophysitis, including abstracts of scientific meetings, in English and Japanese.

METHODS

We searched for information about IgG4-related hypophysitis in PubMed and Igakuchuozasshi (Japan Medical Abstracts Society). Among 104 case reports found, we reviewed 84 fulfilling Leporati's diagnostic criteria.

RESULTS

The mean ±  SD age of onset was 64.2  ±  13.9, 67.5  ±  9.8, and 56.4  ±  18.6 years for all subjects, men, and women, respectively. Men:women was 2.4:1. On magnetic resonance imaging, pituitary, stalk, and pituitary-stalk mass were observed at frequencies of 14.3, 21.4, and 64.3%, respectively. Manifestations were anterior hypopituitarism in 26.2% (22 cases), central diabetes insipidus in 17.9% (15 cases), and panhypopituitarism in 52.4% (44 cases). The median level of serum IgG4 was 264.5 mg/dL for all subjects, 405 mg/dL for men, and 226 mg/dL for women. The mean number of IgG4-related systemic diseases was 2.7  ±  1.5 in all subjects, 3.0  ±  1.5 in men, and 1.8  ±  1.1 in women. Among the IgG4-related diseases, retroperitoneal fibrosis was the most frequent (26.2%), followed by salivary gland diseases (25%). Glucocorticoid therapy was generally effective, except for two cases that received replacement doses. There were significant differences between sexes in terms of age, serum IgG4 levels, and number of IgG4-related diseases.

CONCLUSION

IgG4-related hypophysitis may have different clinical characteristics between genders. This survey may lack some information because the Japanese abstracts did not contain certain details.

Hypophysitis Secondary to Cytotoxic T-Lymphocyte-Associated Protein 4 Blockade: Insights into Pathogenesis from an Autopsy Series

Hypophysitis that develops in cancer patients treated with monoclonal antibodies blocking cytotoxic T-lymphocyte-associated protein 4 (CTLA-4; an inhibitory molecule classically expressed on T cells) is now reported at an incidence of approximately 10%. Its pathogenesis is unknown, in part because no pathologic examination of the pituitary gland has been reported to date. We analyzed at autopsy the pituitary glands of six cancer patients treated with CTLA-4 blockade, one with clinical and pathologic evidence of hypophysitis, one with mild lymphocytic infiltration in the pituitary gland but no clinical signs of hypophysitis, and four with normal pituitary structure and function. CTLA-4 antigen was expressed by pituitary endocrine cells in all patients but at different levels. The highest levels were found in the patient who had clinical and pathologic evidence of severe hypophysitis. This high pituitary CTLA-4 expression was associated with T-cell infiltration and IgG-dependent complement fixation and phagocytosis, immune reactions that induced an extensive destruction of the adenohypophyseal architecture. Pituitary CTLA-4 expression was confirmed in a validation group of 37 surgical pituitary adenomas and 11 normal pituitary glands. The study suggests that administration of CTLA-4 blocking antibodies to patients who express high levels of CTLA-4 antigen in the pituitary can cause an aggressive (necrotizing) form of hypophysitis through type IV (T-cell dependent) and type II (IgG dependent) immune mechanisms.

Revisitation of autoimmune hypophysitis: knowledge and uncertainties on pathophysiological and clinical aspects

PURPOSE

This publication reviews the accepted knowledges and the findings still discussed on several features of autoimmune hypophysitis, including the most recently described forms, such as IgG4 and cancer immunotherapy- related hypophysitis.

METHODS

The most characteristic findings and the pending controversies were derived from a literature review and previous personal experiences. A single paragraph focused on some atypical examples of the disease presenting under confounding pretences.

RESULTS

Headache, visual field alterations and impaired pituitary secretion are the most frequent clinical findings of the disease. Pituitary biopsy, still considered the gold diagnostic standard, does not always receive consent from the patients. The role of magnetic resonance imaging is limited, as this disease may generate images similar to those of other diseases. The role of antipituitary and antihypothalamus antibodies is still discussed owing to methodological difficulties and also because the findings on the true pituitary antigen(s) are still debated. However, the low sensitivity and specificity of immunofluorescence, one of the more widely employed methods to detect these antibodies, may be improved, considering a predetermined cut-off titre and a particular kind of immunostaining.

CONCLUSION

Autoimmune hypophysitis is a multifaceted disease, which may certainly be diagnosed by pituitary biopsy. However, the possible different clinical, laboratory and imaging features must be considered by the physician to avoid a misdiagnosis when examining a possibly affected patient. Therapeutic choice has to be made taking into account the clinical conditions and the degree of hypothalamic-pituitary involvement, but also considering that spontaneous remissions can occur.

Nivolumab-induced hypophysitis in a patient with advanced malignant melanoma

The anti-programmed cell death-1 monoclonal antibody (mab), nivolumab has recently been approved for the treatment of unresectable or metastatic malignant melanoma and non-small-cell lung cancers in Japan. Ipilimumab, an anti-cytotoxic T lymphocyte antigen-4 mab for malignant melanoma that was approved earlier than nivolumab in Western countries, is known to frequently cause endocrine immune-related adverse events such as hypophysitis and thyroid dysfunction. We herein report a patient with advanced melanoma who appeared to develop hypophysitis as a consequence of the inhibition of PD-1 by nivolumab. One week after the 6^th administration of nivolumab, the patient developed progressive fatigue and appetite loss. Laboratory data on admission for the 7^th administration of nivolumab showed eosinophilia and hyponatremia. Since ACTH and cortisol levels were low, nivolumab was discontinued and a large dose of hydrocortisone (100 mg/d) was promptly administered intravenously. A magnetic resonance imaging scan revealed the mild enlargement of the anterior pituitary gland and thickening of the stalk with homogenous contrast. A detailed assessment of anterior pituitary functions with hypothalamic hormone challenges showed that hormonal secretions other than ACTH and TSH were normal. With a replacement dose of hydrocortisone (20 mg/d), the 7^th administration of nivolumab was completed without exacerbating the patient's general condition. The present report provides the first detailed endocrinological presentation of nivolumab-induced hypophysitis showing the enlargement of the pituitary gland and stalk in a malignant melanoma patient in Japan. Oncologists and endocrinologists need to be familiar with potentially life-threatening hypophysitis induced by immune-checkpoint inhibitors.

Hypophysitis: Evaluation and Management

Hypophysitis is the acute or chronic inflammation of the pituitary gland. The spectrum of hypophysitis has expanded in recent years with the addition of two histologic subtypes and recognition as a complication of treatment with immune checkpoint inhibitors. Despite the increased number of published cases, the pathogenesis of hypophysitis is poorly understood, and treatment strategies are diverse and controversial. The diagnosis of hypophysitis generally requires histopathologic confirmation. The presentation and clinical course of hypophysitis varies. Hypophysitis can resolve spontaneously, relapse may occur, and some cases can be refractory to treatment.

Diagnosis of Primary Hypophysitis in Germany

CONTEXT

Representative data on diagnostic findings in primary hypophysitis (PrHy) are scarce.

OBJECTIVE

The objective of the study was to collate consistent data on clinical features in a large series of patients with PrHy. Another objective was to gain information on current practice in a diagnostic work-up.

DESIGN

The Pituitary Working Group of the German Society of Endocrinology conducted a nationwide retrospective cross-sectional cohort study in Germany.

PATIENTS

Seventy-six patients with PrHy were identified.

MAIN OUTCOME MEASURES

Clinical and endocrinological features were assessed.

RESULTS

Headache (50%) and increase in body mass (18%) were the most frequent nonendocrine symptoms. Hypophysitis was associated with pregnancy in only 11% of the female patients. Diabetes insipidus was found in 54% of the patients at presentation. Hypogonadotropic hypogonadism was the most frequent endocrine failure (62%), whereas GH deficiency was the least frequent (37%). With 86%, thickening of the pituitary stalk was the prevailing neuroradiological sign. Compared with surgical cases, the cases without histological confirmation presented more often with suprasellar lesions and had less severe nonendocrine symptoms. Granulomatous hypophysitis was associated with more severe clinical symptoms than lymphocytic hypophysitis. Examination of cerebrospinal fluid was predominantly performed in participating neurosurgical centers, whereas thyroid antibodies were almost exclusively assessed in endocrinological centers.

CONCLUSION

In contrast to the literature, hypogonadism was found to be the most frequent endocrine failure in PrHy. Weight gain was identified as a clinical sign of PrHy. In the majority of patients, PrHy can be reliably identified by characteristic clinical signs and symptoms, obviating histological confirmation. The diagnostic approach should be standardized in PrHy.

Autoimmune lymphocytic hypophysitis in association with autoimmune eye disease and sequential treatment with infliximab and rituximab

INTRODUCTION

Autoimmune lymphocytic hypophysitis associates predominantly with other autoimmune endocrinopathies and is most commonly treated with glucocorticoids and/or decompressive pituitary surgery. Here we report a new association and treatment modality for lymphocytic hypophysitis.

METHODS

A 52-year-old woman presented with scleritis, uveitis, facial palsy, and central diabetes insipidus, accompanied by thickened pituitary stalk and enlarged pituitary on cranial MRI. Neurosarcoidosis was suspected and treatment with glucocorticoids and methotrexate initiated. Since symptoms persisted, infliximab (a monoclonal antibody that antagonizes tumor necrosis factor alpha) was added to her regimen. The patient initially improved but after 6 months developed recurrent pituitary enlargement, bilateral optic neuritis, and panhypopituitarism. To ascertain the nature of the pituitary lesion, she underwent transsphenoidal biopsy, which revealed lymphocytic hypophysitis with numerous CD20 positive B lymphocytes. The pathological finding suggested to us that administration of rituximab (a monoclonal antibody that lyzes B cells expressing CD20) could be useful. Following two courses of rituximab, the pituitary mass resolved and the corticotroph axis partially recovered. The patient has remained in remission during 3 years of follow up.

CONCLUSION

This is the first report of hypophysitis occurring with the triad of scleritis, uveitis, and optic neuritis, as well as the first immunotherapy based on the sequential use of infliximab and rituximab.

Rabphilin-3A as a Targeted Autoantigen in Lymphocytic Infundibulo-neurohypophysitis

CONTEXT

Central diabetes insipidus (CDI) can be caused by several diseases, but in about half of the patients the etiological diagnosis remains unknown. Lymphocytic infundibulo-neurohypophysitis (LINH) is an increasingly recognized entity among cases of idiopathic CDI; however, the differential diagnosis from other pituitary diseases including tumors can be difficult because of similar clinical and radiological manifestations. The definite diagnosis of LINH requires invasive pituitary biopsy.

OBJECTIVE

The study was designed to identify the autoantigen(s) in LINH and thus develop a diagnostic test based on serum autoantibodies.

DESIGN

Rat posterior pituitary lysate was immunoprecipitated with IgGs purified from the sera of patients with LINH or control subjects. The immunoprecipitates were subjected to liquid chromatography-tandem mass spectrometry to screen for pituitary autoantigens of LINH. Subsequently, we made recombinant proteins of candidate autoantigens and analyzed autoantibodies in serum by Western blotting.

RESULTS

Rabphilin-3A proved to be the most diagnostically useful autoantigen. Anti-rabphilin-3A antibodies were detected in 22 of the 29 (76%) patients (including 4 of the 4 biopsy-proven samples) with LINH and 2 of 18 (11.1%) patients with biopsy-proven lymphocytic adeno-hypophysitis. In contrast, these antibodies were absent in patients with biopsy-proven sellar/suprasellar masses without lymphocytic hypophysitis (n = 34), including 18 patients with CDI. Rabphilin-3A was expressed in posterior pituitary and hypothalamic vasopressin neurons but not anterior pituitary.

CONCLUSIONS

These results suggest that rabphilin-3A is a major autoantigen in LINH. Autoantibodies to rabphilin-3A may serve as a biomarker for the diagnosis of LINH and be useful for the differential diagnosis in patients with CDI.

A Case of IgG4-Related Hypophysitis Presented with Hypopituitarism and Diabetes Insipidus

Immunoglobulin (Ig) G4-related systemic syndrome is a recently described entity characterized by elevated serum IgG4 and tissue infiltration of IgG4-positive plasma cells. Pituitary gland can be involved as hypophysitis. We report a case of a 72-year-old man, who presented with general fatigue and weakness. Laboratory tests revealed diabetes insipidus as well as hypopituitarism including adrenal insufficiency, hypogonadism, and hypothyroidism. His serum IgG4 was elevated. MR images showed enlargement of the pituitary stalk. Multiple nodules in bilateral kidneys were pointed out in the abdominal CT. Histological examination of the nodules showed increased IgG4-positive plasma cells. We diagnosed him with IgG4-related kidney disease and hypophysitis. After treatment with hydrocortisone, his symptoms improved. The follow-up images showed that almost all renal nodules disap-peared and his pituitary stalk was shrinking. Our case appears to be very sensitive to glucocorticoid and suggests the possibility of treating IgG4-related hypophysitis successfully with a lower dose of glucocorticoid.

Hypophysitis

In this article, an overview is presented of hypophysitis in terms of current clinical and experimental findings, with discussion of the anatomic and histopathologic classification of primary hypophysitis and factors associated with secondary hypophysitis. In addition, discusses the pathophysiology, clinical features, management, and prognosis associated with this disease are discussed.

Primary (autoimmune) hypophysitis: a single centre experience

BACKGROUND

Autoimmune hypophysitis (AH) is a rare autoimmune inflammatory disorder of pituitary gland.

OBJECTIVE

To analyse clinical, hormonal, radiological features and management outcomes of AH.

DESIGN

Retrospective analysis of patients with primary hypophysitis (where secondary causes of hypophysitis were ruled out) was carried out from 2006 to 2012. AH emerged as the most plausible aetiology and the diagnosis of exclusion.

RESULTS

Twenty-four patients with AH (21 females and 3 males) were evaluated. They presented with symptoms of expanding sellar mass (83.3%), symptoms of anterior pituitary hormone deficiencies (58.3%), and diabetes insipidus (16.7%). The anterior pituitary hormonal axes affected were cortisol (75%), thyroid (58.33%) and gonadotropin (50%). All had sellar mass on magnetic resonance imaging, which was symmetrical (91.7%) and homogenously enhancing (91.7%). Stalk thickening, suprasellar extension, loss of posterior pituitary hyperintensity and parasellar T2 dark sign were seen in 87.5, 87.5, 71.5, and 50% respectively. In addition to hormone replacement, five (20.83%) patients underwent trans-sphenoidal surgery, fifteen (62.5%) were watchfully monitored, while four cases (16.67%) received steroid pulse therapy. On follow up imaging, the sellar mass regressed in all, while, stalk thickening was persistent in 13/19 (68.4%) non-operated patients at median follow up of 1 year. Pituitary hormone axis recovery was seen in 10 (41.67%) and was seen in cortisol 10/18 (55.5%) followed by gonadotropin 5/12 (41.67%) axis.

CONCLUSION

Characteristic radiology helps in diagnosis of AH even without tissue diagnosis. Non-operative treatment is the preferred treatment modality. Steroid pulse therapy potentially improves pituitary axis recovery.

Histologically confirmed isolated IgG4-related hypophysitis: two case reports in young women

IgG4-related hypophysitis is a recently described entity belonging to the group of IgG4-related diseases. Many other organs can also be affected, and it is more common in older men. To date, 32 cases of IgG4-related hypophysitis have been reported in the literature, 11 of which included confirmatory tissue biopsy and the majority affecting multiple organs. The aim of this report is to present two cases of biopsy-proven IgG4-related hypophysitis occurring in two young female patients with no evidence of involvement of other organs at the time of diagnosis.

LEARNING POINTS

IgG4-related hypophysitis belongs to the group of IgG4-related diseases, and is a fibro-inflammatory condition characterized by dense lymphoplasmacytic infiltrates rich in IgG4-positive plasma cells and storiform fibrosis.It is more common in older men, but young women may also present this type of hypophysitis.Although involvement of other organs is frequent, isolated pituitary disease is possible.Frequent clinical manifestations include anterior hypopituitarism and/or diabetes insipidus.THE DIAGNOSIS MAY BE CONFIRMED WITH ANY OF THE FOLLOWING CRITERIA: a pituitary biopsy with lymphoplasmacytic infiltrates, with more than ten IgG4-positive cells; a sellar mass and/or thickened pituitary stalk and a biopsy-proven involvement of another organ; a sellar mass and/or thickened pituitary stalk and IgG4 serum levels >140 mg/dl and sellar mass reduction and symptom improvement after corticosteroid treatment.Glucocorticoids are recommended as first-line therapy.

Use of serum pituitary antibodies to improve the diagnosis of hypophysitis

Lymphocytic hypophysitis is characterized by an extensive infiltration of lymphocytic cells. Pituitary biopsy is the gold diagnostic standard for lymphocytic hypophysitis but the disease occurs with moderate or without pituitary enlargement. The role of antipituitary antibodies (APA) in autoimmune hypophysitis is still discussed due to various methodological difficulties. Indirect immunofluorescence, a widely employed method to detect APA at this time produces highly variable results due to the use of human or animal pituitary substrates. For many years the authors have conducted a re-evaluation of APA by immunofluorescence in patients with other autoimmune diseases and in patients with apparently idiopathic hypopituitarism, using pituitary from young baboons as substrate but considering a predetermined cut-off of the titer and immunofluorescence pattern. This procedure allowed us to find out those with autoimmune pituitary impairment and to foresee the kind of future hypopituitarism in those with pituitary function still normal. Moreover, in APA positive patients, the use of a second step of a double immunofluorescence method allowed identification of the pituitary cells targeted by APA, verifying the correspondence with the kind of hypopituitarism, also when present in subclinical stage. However, to carry out an international workshop comparing the detection of APA by immunofluorescence using different substrates could contribute to verify the best choice to improve the sensitivity and specificity of this method.

The prevalence of IgG4-related hypophysitis in 170 consecutive patients with hypopituitarism and/or central diabetes insipidus and review of the literature

OBJECTIVE

The prevalence and clinical characteristics of IgG4-related hypophysitis remain unclear due to the limited number of case reports. Therefore, in this study, we screened consecutive outpatients with hypopituitarism and/or diabetes insipidus (DI) to estimate its prevalence.

METHODS

A total of 170 consecutive outpatients with hypopituitarism and/or central DI were screened at Kobe University Hospital for detecting IgG4-related hypophysitis by pituitary magnetic resonance imaging, measuring serum IgG4 concentrations, assessing the involvement of other organs, and carrying out an immunohistochemical analysis to detect IgG4-positive cell infiltration.

RESULTS

Among the screened cases, 116 cases were excluded due to diagnosis of other causes such as tumors and congenital abnormalities. Additionally, 22 cases with isolated ACTH deficiency were analyzed and were found not to meet the criteria of IgG4-related hypophysitis. The remaining 32 cases were screened and seven were diagnosed with IgG4-related hypophysitis, of which three cases were diagnosed by analyzing pituitary specimens. IgG4-related hypophysitis was detected in 30% (seven of 23 patients) of hypophysitis cases and 4% of all hypopituitarism/DI cases. The mean age at the onset of IgG4-related hypophysitis was 61.8±8.8 years, and the serum IgG4 concentration was 191.1±78.3 mg/dl (normal values 5-105 mg/dl and values in IgG4-related disease (RD) ≥135 mg/dl). Pituitary gland and/or stalk swelling was observed in six patients, and an empty sella was observed in one patient. Multiple co-existing organ involvement was observed in four of the seven patients prior to the onset of IgG4-related hypophysitis.

CONCLUSION

These data suggest that the prevalence of IgG4-related hypophysitis has been underestimated. We should also consider the possibility of the development of hypopituitarism/DI caused by IgG4-related hypophysitis during the clinical course of other IgG4-RDs.

Prednisolone markedly reduced serum IgG4 levels along with the improvement of pituitary mass and anterior pituitary function in a patient with IgG4-related infundibulo-hypophysitis

In 2011 a 76 year-old man with a medical history of diabetes, hypertension and autoimmune pancreatitis was admitted to our hospital because of anorexia, general malaise and repeated hypoglycemia. When he was 72 years old, he suffered from pancreatitis, and pancreas head tumor was operated. IgG4-related pancreatitis was diagnosed histopathologically. On admission anterior pituitary function test revealed impaired response of ACTH and cortisol to CRH, and no response of GH, TSH and gonadotropin to GHRH, TRH and LHRH, respectively. Baseline PRL level was elevated. Serum IgG and IgG4 levels were markedly elevated. Pituitary MRI showed significant enlargement of pituitary gland and stalk. Chest CT suggested IgG4-related lung disease. IgG4-related infundibulo-hypophysitis was diagnosed based on the above mentioned past history and results of present examinations. Twenty mg of hydrocortisone, followed by 20 mg of prednisolone (PSL) and 25 μg of levothyroxine markedly reduced serum IgG4 levels and ameliorated the symptom, the size of pituitary and stalk, and anterior pituitary function (TSH, GH and gonadotropin), although diabetes insipidus became apparent due to glucocorticoid administration. This is a typical case of IgG4-related hypophysitis in which PSL causes marked improvement of pituitary mass and pituitary function along with the reduction of serum IgG4 levels.