A diagnostic pitfall in IgG4-related hypophysitis: infiltration of IgG4-positive cells in the pituitary of granulomatosis with polyangiitis

Secondary hypophysitis associated with Rathke's cleft cyst resembling a pituitary abscess

Background

Although rare, cases of hypophysitis resembling a pituitary abscess (PA) have been reported. Differential diagnosis between hypophysitis and PA is crucial as the two diseases require different treatments.

Case Description

A 38-year-old woman with headaches underwent head magnetic resonance imaging (MRI), which revealed an 11-mm mass lesion in the sella turcica. Due to breastfeeding, contrast-enhanced MRI was avoided. Pituitary adenomas and Rathke's cleft cyst (RCC) were suspected, and she was initially treated conservatively. Five months later, she acquired syndrome coronavirus two infections, and while the fever subsided with acetaminophen, the headache persisted. One month later, the headache worsened, followed by fever and diabetes insipidus. MRI revealed a pituitary cystic mass with ring-shaped contrast enhancement on T1-weighted MRI and increased signal intensity on diffusion-weighted imaging (DWI). PA was suspected, and emergency endoscopic transsphenoidal surgery was performed. The microbiological examination of the yellowish-brown content drained from the cystic mass was negative. Microscopically, the cystic lesion was covered with ciliated columnar epithelium and stratified squamous epithelium, with a dense inflammatory cell infiltrate consisting mainly of lymphocytes and plasma cells observed around the cyst. This supported the diagnosis of secondary hypophysitis associated with RCC without PA.

Conclusion

We report a case of hypophysitis secondary to RCC resembling PA with ring-shaped contrast enhancement on MRI and increased signal intensity on DWI. This case emphasizes the need for cautious diagnosis of secondary hypophysitis due to RCC in individuals with MRIs and clinical manifestations resembling an abscess.

Granulomatosis with polyangiitis in a patient with polydipsia, facial nerve paralysis, and severe otologic complaints: a case report and review of the literature

BACKGROUND

Granulomatosis with polyangiitis, formerly known as Wegener granulomatosis, is a necrotizing vasculitis with granulomatous inflammation that belongs to the class of antineutrophil cytoplasmic antibodies-positive diseases. It occurs in a localized and a systemic form and may present with a variety of symptoms. Involvement of the upper respiratory tract is very common, while neurologic, endocrinological, and nephrological dysfunction may occur.

CASE PRESENTATION

We describe the case of a 29-year-old Central European male patient presenting with severe bilateral sensorineural hearing loss, otorrhea, and one-sided facial nerve paralysis. The patient was unsuccessfully treated with i.v. antibiotics at another hospital in Berlin, and tympanic tubes were inserted. After presentation to our emergency room, he was hospitalized and further diagnostics started. Increased fluid intake and 12 kg weight gain over the last months were reported. The patient was diagnosed with granulomatosis with polyangiitis and diabetes insipidus. The patient's condition improved after treatment with rituximab.

DISCUSSION

A comprehensive PubMed search of all articles with granulomatosis with polyangiitis and diabetes insipidus was conducted to assess which combination of symptoms occurs simultaneously and whether other parts of the pituitary are commonly involved. The 39 selected articles, describing 61 patients, showed that ear-nose-throat involvement occurred most commonly, in 71% of cases. Of patients, 59% had involvement of the anterior pituitary gland, while true panhypopituitarism occurred in 13% of cases. Only one case report featured the same set of symptoms as described herein.

CONCLUSION

Granulomatosis with polyangiitis is a highly variable disease, commonly involving the upper airways, but that may present with symptoms solely related to the pituitary gland. Clinicians should have a low threshold to investigate for granulomatosis with polyangiitis in patients with therapy-resistant otorrhea. Patients may present with a complex set of symptoms, and integrating different specialists when additional symptoms occur may lead to faster diagnosis.

Sellar germinoma mimicking IgG4-related hypophysitis: a case report

BACKGROUND

The differential diagnosis of IgG4-related hypophysitis and other inflammatory diseases or tumors involving sellar region is challenging even after sellar biopsy. Sellar germinoma is usually infiltrated by lymphocytes or plasma cells, and may be confused with hypophysitis.

CASE PRESENTATION

A 36-year-old man with diabetes insipidus, elevated serum IgG4 level (336 mg/dl), and sellar mass was suspected to have IgG4-related hypophysitis, and no other lesion of IgG4-related disease was detected. After treated by prednisone and mycophenolate mofetil, the serum IgG4 decreased to 214 mg/dl. However, after withdrawal of the drugs, the IgG4 level increased to 308 mg/dl. Endocrine assessments revealed panhypopituitarism, and the sellar mass enlarged. Transsphenoidal sellar exploration and biopsy was conducted. Pathological examination showed that the lesion was germinoma with lymphocytes and plasma cells infiltration, and IgG4-staining was positive (70/HPF, IgG4/IgG ratio = 10%). The patient was then treated by cisplatin and etoposide. After four cycles of chemotherapy, the serum IgG4 was 201 mg/dl, and the sellar mass was invisible.

CONCLUSION

Sellar germinoma can mimic the clinical characteristics of IgG4-related hypophysitis. Poor response to glucocorticoids can be used as an exclusion criterion in the clinical diagnosis of IgG4-related hypophysitis.

Anti-Neuronal IgG4 Autoimmune Diseases and IgG4-Related Diseases May Not Be Part of the Same Spectrum: A Comparative Study

Background

IgG4 is associated with two emerging groups of rare diseases: 1) IgG4 autoimmune diseases (IgG4-AID) and 2) IgG4-related diseases (IgG4-RLD). Anti-neuronal IgG4-AID include MuSK myasthenia gravis, LGI1- and Caspr2-encephalitis and autoimmune nodo-/paranodopathies (CNTN1/Caspr1 or NF155 antibodies). IgG4-RLD is a multiorgan disease hallmarked by tissue-destructive fibrotic lesions with lymphocyte and IgG4 plasma cell infiltrates and increased serum IgG4 concentrations. It is unclear whether IgG4-AID and IgG4-RLD share relevant clinical and immunopathological features.

Methods

We collected and analyzed clinical, serological, and histopathological data in 50 patients with anti-neuronal IgG4-AID and 19 patients with IgG4-RLD.

Results

A significantly higher proportion of IgG4-RLD patients had serum IgG4 elevation when compared to IgG4-AID patients (52.63% vs. 16%, p = .004). Moreover, those IgG4-AID patients with elevated IgG4 did not meet the diagnostic criteria of IgG4-RLD, and their autoantibody titers did not correlate with their serum IgG4 concentrations. In addition, patients with IgG4-RLD were negative for anti-neuronal/neuromuscular autoantibodies and among these patients, men showed a significantly higher propensity for IgG4 elevation, when compared to women (p = .005). Last, a kidney biopsy from a patient with autoimmune paranodopathy due to CNTN1/Caspr1-complex IgG4 autoantibodies and concomitant nephrotic syndrome did not show fibrosis or IgG4+ plasma cells, which are diagnostic hallmarks of IgG4-RLD.

Conclusion

Our observations suggest that anti-neuronal IgG4-AID and IgG4-RLD are most likely distinct disease entities.

Human pituitary development and application of iPSCs for pituitary disease

The pituitary plays a pivotal role in maintaining systemic homeostasis by secreting several hormones. During fetal development, the pituitary develops from the oral ectoderm in contact with the adjacent hypothalamus. This process is regulated by the fine-tuned expression of transcription and growth factors. Impairments of this process result in congenital pituitary hypoplasia leading to dysfunction of the pituitary. Although animal models such as knockout mice have helped to clarify these underlying mechanisms, the developmental processes of the human pituitary gland and the mechanisms of human pituitary disorders have not been fully understood. This is because, at least in part, of the lack of a human pituitary developmental model. Recently, methods for in vitro induction of the pituitary gland from human pluripotent stem cells were developed. These models can be utilized not only for regenerative medicine but also for human pituitary studies on developmental biology and for modeling of pituitary disorders, such as hypopituitarism and pituitary tumors. In this review, we provide an overview of recent progress in the applications of pluripotent stem cells for pituitary research and discuss further perspectives for pituitary studies.

Histopathological findings in the landscape of IgG4-related pathology in patients with pituitary dysfunction: Review of six cases

IgG4-related hypophysitis (IgG4-RH) is increasingly being reported as an isolated entity or, less frequently, as a manifestation of a multiorgan IgG4-related disease (IgG4-RD), in which typical histopathology is a cornerstone for the diagnosis. We aimed to describe the histopathological changes in the surgical specimens from patients with clinical signs of pituitary disease that fulfilled the current diagnostic criteria for IgG4-RH. Histopathological features were correlated with clinical and radiological findings. Of 19 patients with pituitary dysfunction and inflammatory changes in the surgical pituitary specimen operated on during 2011-2019, we identified five patients with typical IgG4-related pathology (lymphoplasmacytic infiltration with more than 10 IgG4-positive plasma cells per one high power microscopic field, representing at least 40% of all plasma cells and at least focal storiform fibrosis). One patient with diabetes insipidus and pachymeningitis with IgG4-related changes in a biopsy from the dura was also included. Additional histopathological changes that typically are not part of the IgG4-RH were observed: Rathke's cleft cyst in four and granulomatous changes in two patients. One patient had an elevated serum IgG4 level and systemic manifestations that could be associated with the systemic IgG4-RD. Our findings indicate that pure IgG4-RH is uncommon. All patients with pituitary dysfunction, beyond typical IgG4-related pathology, had other pathological findings that could trigger the secondary IgG4-response. Both primary pathology and secondary IgG4-related features should be reported in patients with pituitary dysfunction because their co-occurrence may cause atypical clinical and imaging features, and unexpected response to surgical and pharmacological treatment. The current criteria for the diagnosis of IgG4-RH can lead to overdiagnosis of IgG4-RH if additional pathological changes are not taken into consideration. The classification criteria of IgG4-RD proposed by the American College of Rheumatology/European League Against Rheumatism could help classify patients more properly as IgG4-RH if applied to the pituitary gland.

Update on IgG4-mediated autoimmune diseases: New insights and new family members

Antibodies of IgG4 subclass are exceptional players of the immune system, as they are considered to be immunologically inert and functionally monovalent, and as such may be part of classical tolerance mechanisms. IgG4 antibodies are found in a range of different diseases, including IgG4-related diseases, allergy, cancer, rheumatoid arthritis, helminth infection and IgG4 autoimmune diseases, where they may be pathogenic or protective. IgG4 autoimmune diseases are an emerging new group of diseases that are characterized by pathogenic, antigen-specific autoantibodies of IgG4 subclass, such as MuSK myasthenia gravis, pemphigus vulgaris and thrombotic thrombocytopenic purpura. The list of IgG4 autoantigens is rapidly growing and to date contains 29 candidate antigens. Interestingly, IgG4 autoimmune diseases are restricted to four distinct organs: 1) the central and peripheral nervous system, 2) the kidney, 3) the skin and mucous membranes and 4) the vascular system and soluble antigens in the blood circulation. The pathogenicity of IgG4 can be validated using our classification system, and is usually excerted by functional blocking of protein-protein interaction.

Diagnosis and treatment of autoimmune and IgG4-related hypophysitis: clinical guidelines of the Japan Endocrine Society

Hypophysitis, which is often accompanied by pituitary dysfunction, is classified into several subtypes based on the cause, histology, and the location of inflammation in the pituitary gland. A definitive diagnosis requires pituitary biopsy, which is invasive, and the process is limited to specialized clinical settings. In this opinion paper, we review the literature associated with hypophysitis, and provide the guidelines of the Japan Endocrine Society for the diagnosis and treatment of autoimmune and IgG4-related hypophysitis.

IgG4:IgG RNA ratio differentiates active disease from remission in granulomatosis with polyangiitis: a new disease activity marker? A cross-sectional and longitudinal study

OBJECTIVES

An important limitation in granulomatosis with polyangiitis (GPA) is the lack of disease activity markers. Immunoglobulin G4-positive (IgG4+) B cells and plasma cells are implicated in the pathogenesis of GPA. We hypothesized that the presence of these cells in peripheral blood could serve as disease activity parameter in GPA.

METHODS

We included 35 proteinase 3-antineutrophil cytoplasmic antibodies-positive patients with GPA in a cross-sectional study. Active disease was defined as Birmingham Vasculitis Activity Score (BVAS) ≥ 3 (n = 15), remission as BVAS of 0 (n = 17), and low disease activity (LDA) as BVAS of 1-2 and clinical remission (n = 3). Healthy subjects (n = 10), patients with systemic lupus erythematosus (n = 24), and patients with rheumatoid arthritis (n = 19) functioned as control subjects. An additional longitudinal study was performed in ten patients with GPA. Using a validated qPCR test, we measured the IgG4:IgG RNA ratio in all groups and compared the results with known biomarkers.

RESULTS

The median qPCR score was higher in active GPA (21.4; IQR 12.1-29.6) than in remission/LDA (3.3; IQR 1.6-5.6) (Mann-Whitney U test, p < 0.0001) and outperformed other known disease activity parameters in detecting activity. A cutoff qPCR score of 11.2% differentiated active disease from remission/LDA accurately (AUC 0.993). The qPCR test correlated well with the BVAS (Spearman r = 0.77, p < 0.0001). In the longitudinal study, a decrease in BVAS correlated with qPCR score reduction (paired t test, p < 0.05).

CONCLUSIONS

The IgG4:IgG RNA ratio in GPA accurately distinguishes active disease from remission and correlates well with disease activity in these single-center studies. If these results are confirmed in larger longitudinal studies, this test might help to steer treatment decisions in patients with GPA.

Severe ophthalmic manifestation in pituitary-involved granulomatosis with polyangiitis: a case report and literature review

BACKGROUND

Granulomatosis with polyangiitis (GPA), a necrotizing granulomatous disease, very rarely involves the central nervous system (CNS), particularly the pituitary. Delayed treatment may cause permanent bilateral blindness. We report an isolated case of pituitary GPA that manifested as a progressive bilateral temporal visual field (VF) defect and was diagnosed via pituitary biopsy. Additionally, we review ocular, chiasmal and cranial nerve involvement in pituitary GPA.

CASE PRESENTATION

A 20-year-old Chinese man was referred for repeated fever, sudden headache, diplopia with a bilateral best-corrected visual acuity (BCVA) of 10/20, ptosis in both eyes and restricted abduction on the right side. VF tests showed bitemporal hemianopsia. Laboratory tests revealed hypothyroidism and were negative for autoimmune markers. Enhanced magnetic resonance imaging (MRI) showed pituitary enlargement. The diagnosis was lymphocytic pituitaritis. After intravenous (IV) dexamethasone treatment, full recovery occurred within 2 months. Two years later, the patient was readmitted for headache recurrence. With oral prednisone, the visual acuity in his right eye rapidly decreased to hand motion (HM) within one month. Enhanced MRI showed pituitary enlargement and a new, invasive suprasellar CNS lesion. All infection- and autoimmune-related tests were negative. The visual acuity in his right and left eye decreased to no light perception (NLP) after 6 days and 2 weeks, respectively. The biopsy results suggested GPA. After IV methylprednisolone treatment, complete remission of the symptoms occurred and was confirmed by MRI. The 15-month follow-up showed no signs of recurrence.

CONCLUSION

GPA typically affects the respiratory tract, lungs and kidneys. To date, 50 cases with pituitary involvement have been reported. Chiasmal and cranial nerve involvement leading to visual acuity impairment are common. We found 2 cases with severe visual loss resembling our case and discuss certain similarities.

Hypophyseal Involvement in Immunoglobulin G4-Related Disease: A Retrospective Study from a Single Tertiary Center

This study aims to outline the clinical features and outcomes of IgG4-related hypophysitis (IgG4-RH) patients in a tertiary medical center. We reviewed clinical manifestations and imaging and pituitary function tests at baseline, as well as during follow-up. Ten patients were included. The mean age at diagnosis of IgG4-RH was 48.4 (16.0-64.0) years. An average of 3 (0-9) extrapituitary organs were involved. Five patients had panhypopituitarism, three had only posterior hypopituitarism, one had only anterior hypopituitarism, and one had a normal pituitary function. One patient in our study had pituitary mass biopsy, lacking IgG4-positive cells despite lymphocyte infiltration forming an inflammatory pseudotumor. Five patients with a clinical course of IgG4-RH less than nine months and a whole course of IgG4-RD less than two years were managed with glucocorticoids, while three patients with a longer history were administered glucocorticoids plus immunosuppressive agents. One patient went through surgical excision, and one patient was lost to follow-up. All patients showed a prompt response clinically, but only three patients had normalized serum IgG4 levels. Two patients who took medications for less than six months relapsed. Conclusions. IgG4-RD is a broad disease, and all physicians involved have to be aware of the possibility of pituitary dysfunction. Younger patients should be expected. The histopathological feature of pituitary gland biopsy could be atypical. For patients with a longer history, the combination of GC and immunosuppressive agents is favorable. Early and adequate courses of treatment are crucial for the management of IgG4-RH. With GC and/or immunosuppressant treatment, however, pituitary function or diabetes insipidus did not improve considerably.

Neurological Manifestations of IgG4-Related Disease

OPINION STATEMENT

IgG4-related disease (IgG4-RD) is a multisystem inflammatory disorder. Early recognition of IgG4-RD is important to avoid permanent organ dysfunction and disability. Neurological involvement by IgG4-RD is relatively uncommon, but well recognised-hypertrophic pachymeningitis and hypophysitis are the most frequent manifestations. Although the nervous system may be involved in isolation, this more frequently occurs in conjunction with involvement of other systems. Elevated circulating levels of IgG4 are suggestive of the condition, but these are not pathognomonic and exclusion of other inflammatory disorders including vasculitis is required. Wherever possible, a tissue diagnosis should be established. The characteristic histopathological changes include a lymphoplasmacytoid infiltrate, storiform fibrosis and obliterative phlebitis. IgG4-RD typically responds well to treatment with glucocorticoids, although relapse is relatively common and treatment with a steroid-sparing agent or rituximab may be required. Improved understanding of the pathogenesis of IgG4-RD is likely to lead to the development of more specific disease treatments in the future.

IgG4-Related Hypophysitis: Case Report and Literature Review

IgG4-related hypophysitis is a rare, inflammatory process of the pituitary that mimics more commonly seen pituitary tumors. We report a case of IgG4-related hypophysitis in a 16-year-old female with diabetes insipidus who was found to have IgG4-related hypophysitis based on tissue diagnosis. This entity has not been previously described in a pediatric patient. Recognition of certain inflammatory processes of the pituitary may lead to alternative means of diagnosis and medical management without a biopsy.

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 and management of tumor-like hypophysitis: A retrospective case series

Tumor-like hypophysitis is an uncommon sellar condition that presents as inflammatory lesions on the structures of the pituitary gland. The diagnosis and management of hypophysitis poses a significant challenge, as its clinical manifestation and appearance in imaging studies are difficult to distinguish from that of pituitary tumors. The present retrospective study summarizes two rare cases of primary granulomatous hypophysitis, two cases of lymphocytic hypophysitis, and three cases in which a pathological diagnosis was not determined due to the use of hormone replacement therapy only. The mean age of the patients studied was 45.71±22.16 years, and the patients comprised two males and five females. The clinical signs of hypophysitis included headache, fever, gradual decrease in visual acuity, nausea and vomiting. Enhanced magnetic resonance imaging revealed sellar and pituitary stalk lesions, with iso- or hypodense signals on T1-weighted images. Transsphenoidal surgery was performed in three cases. It was challenging to diagnose hypophysitis due to the lack of any significant specific clinical signs. A transsphenoidal biopsy with fast-frozen pathology is able to diagnose hypophysitis. Glucocorticoid therapy may be a potential treatment for hypophysitis, as complete removal of pituitary masses may disable pituitary function.

Clinical course of IgG4-related hypophysitis presenting with focal seizure and relapsing lymphocytic hypophysitis

BACKGROUND

This is the first case report of focal seizure as a manifestation of Immunoglobulin G4 (IgG4)-related hypophysitis. IgG4-related hypophysitis is a novel category of hypophysitis. The clinical presentations, imaging studies and initial pathology studies can mimic lymphocytic hypophysitis. Here we report additional clinical clues in differentiating these two conditions.

CASE PRESENTATION

A 43-year-old Thai male presented with focal seizure, headache, and anterior pituitary hypofunction. His MRI study showed typical hypophysitis lesion with abnormal cerebral parenchymal signal intensity at right frontal lobe. The pituitary biopsied was obtained and the patient was initially diagnosed with lymphocytic hypophysitis. Following initial low-dose steroid therapy, his seizure and headache resolved but his anterior pituitary hormones remained deficient. However, during steroid tapering, he developed new onset acute visual loss. Upon rigorous pathologic review, his diagnosis of IgG4-related hypophysitis with suspected CNS involvement was established. He was subsequently treated with high-dose steroid and rapidly regained his sight.

CONCLUSION

This case report highlights the important distinguishing features of IgG4-related hypophysitis from lymphocytic hypophysitis. These include the relapsing clinical course of hypophysitis after steroid decrement and concomitant pachymeningitis particularly in middle-aged to elderly Asian male who presented with hypophysitis. With appropriate dosage of steroids, medical treatment is usually sufficient to control the disease and surgical interventions are usually not required.