IgG4-related meningeal disease: clinico-pathological features and proposal for diagnostic criteria

A case report of Immunoglobulin-G4-related hypertrophic sclerosing pachymeningitis

IgG4-related diseases (IgG4-RD) are a group of chronic progressive autoimmune diseases of unknown etiology that are increasingly recognized as an important pathophysiological basis for a variety of systemic diseases. It is thought to involve almost any organ of the body, but the involvement of the central nervous system is relatively rare. We report the case of a 56-year-old male patient admitted to the hospital d recurrent dizziness and nausea for more than 3 months. The preoperative imaging was misdiagnosed as a meningioma, with this lesion demonstrated localized inhomogeneous thickening of the meninges in the left parietal region on T2-weighted and T2 fat suppression sequences with localized nodular changes. The patient's final pathologic diagnosis was IgG4-associated sclerosing thick encephalitis. The diagnosis of IgG4-associated hypertrophic pontine meningitis is challenging. Clinically, IgG4-associated sclerosing diseases usually present as mass-like lesions, which can be easily misdiagnosed as neoplastic lesions due to their similar appearance. These fundamentally recognized autoimmune disorders respond well to corticosteroid therapy. Therefore, accurate detection of IgG4-related disease is critical to prevent patients from undergoing unnecessary surgery.

IgG4-related pachyleptomeningitis with inflammatory pseudotumor

•We report the first case of IgG4-related pachyleptomeningitis.•Our case showed also an inflammatory pseudotumor on the side ipsilateral to the pachyleptomeningitis.•The pachyleptomeningitis is probably due to inflammation from the dural pseudotumor spreading along the adjacent meninges.

IgG4-Related Neurological Disease: A Single Center Ambispective Study from South India

IgG4-related disease (IgG4-RD) is an immune-mediated multi-system disorder. The nervous system (IgG4-RND) is rarely affected. We describe a short case series. We performed an ambispective analysis of IgG4-RND patients admitted at our centre between January 2016 and December 2022. Eight patients (M: F-2:6) were included with a mean age at presentation of 40.63 ± 17.88 years and disease duration of 5.16 ± 4.08 years. The common diseased sites were pachymeninges (7), orbits (4), paranasal sinuses (3), frontal lobe (1), hypophysis (1), leptomeninges (1), and middle ear (1). Common symptoms were headache and cranial neuropathy. The common nerves involved were the optic nerve, followed by the third, fifth, sixth, and seventh. Cerebrospinal fluid showed lymphocytic pleocytosis. Histopathology showed lymphoplasmacytic infiltrate (8), fibrosis (5), >10 IgG4 + cells (7), and IgG4/IgG >40% (6). Six had a relapsing course. The rituximab-based treatment regimen showed a favourable response.

Extensive, circumferential, epidural spinal cord compression by IgG4-related pachymeningitis

A rare case of IgG4-related pachymeningitis is presented. The manuscript describes the multidisciplinary treatment of a rare entity in an exceptional location, prompting emergent surgical treatment. However, the correct intraoperative hypothesis led to a minimal surgical approach with fewer risks and good disease control. Finding a balance between maximising treatment outcome and minimising risks is often difficult for clinicians worldwide who encounter the same clinical dilemma. The known cases are summarised, as are radiological characteristics and common treatments.

A selected case series of idiopathic hypertrophic pachymeningitis in a single center: Pathological characteristics and case-oriented review

Hypertrophic pachymeningitis (HP) is a relatively rare disease of the central nervous system characterized by local or diffuse fibrous thickening of the dura mater. At present, there is still insufficient research on the pathogenesis and treatment strategies of this disease. We reported a continuous case series of seven patients with idiopathic HP (IHP), and also details one case of immunoglobulin G4-related HP requiring surgical intervention. Early diagnosis and appropriate surgical intervention for IHP could prevent the progression of permanent neurological damage and spinal cord paraplegia.

Lymphoplasmacyte-Rich Meningioma or IgG4-Related Disease: Walking the Thin Line

Lymphoplasmacyte-rich meningioma (LP meningioma) is a rare form of grade 1 meningioma. It shows dense lymphoplasmacytic infiltrate, mimicking an inflammatory lesion. We present a case of Lymphoplasmacyte-rich (LP) meningioma in the left parasagittal region in a 47-year-old female. On histological examination, it showed dense lymphoplasmacytic infiltrate masking the meningothelial component. There was dense fibrosis and numerous IgG4-positive plasma cells (100-120/hpf), admixed with lymphocytes and few histiocytes. The meningothelial component was highlighted by epithelial membrane antigen (EMA) immunostain. The patient had normal serum IgG4 level. This case highlights the morphological overlap between LP meningioma and IgG4-related disease. The presence of fibrosis and increased IgG4-positive plasma cells as a major inflammatory component in LP meningioma, as demonstrated in the present case and some other previous studies raise suspicion of its association with IgG4-related disease. However, this hypothesis requires further detailed studies for confirmation.

Epiduritis related to IgG4 disease: A very rare cause for spinal cord compression

Background

Inflammatory pseudotumors are rare, and those attributed to immunoglobulin G4 (IgG4) diseases are even less frequently encountered. Here, we reviewed 41 cases from the literature of spinal inflammatory pseudotumors due to IgG4 and have added our single new case.

Case Presentation

A 25-year-old male presented with progressive back pain, bilateral paraparesis, and sphincter dysfunction. His deficit was attributed to MR-documented posterolateral lesion between the T5 and T10 levels for which he levels underwent a T1-T1010 laminectomy. The pathology revealed an immunoglobulin G4-related inflammatory pseudotumor. Postoperatively, the patient additionally required systemic and epidural administration of glucocorticoids.

Conclusion

IgG4-related disease is an emerging clinical condition that rarely involves the central nervous system. Spinal inflammatory pseudotumors, including IgG4 disease, should be more commonly considered among the potential differential diagnoses of lesions compressing the spinal cord.

Hypertrophic pachymeningitis due to IgG4-related disease (RD-IgG4). A case report

INTRODUCTION

Hypertrophic pachymeningitis (HP) is a clinico-radiological entity characterized by a thickening of the dura mater that may be focal or diffuse and manifested by a variety of neurological syndromes. Aetiologically, it is classified as infectious, neoplastic, autoimmune, and idiopathic. Many of these formerly idiopathic cases have been shown to fall into the spectrum of IgG4-related disease.

OBJECTIVE

To describe the case of a patient attended for neurological involvement due to hypertrophic pachymeningitis with initial diagnosis of inflammatory myofibroblastic tumour and final diagnosis of IgG4-related disease.

CASE

A 25-year-old woman with neurological symptoms of 3 years' evolution characterized initially by right hypoacusis, evolving with headache and diplopia. Magnetic resonance imaging (MRI) of the encephalon showed pachymeningeal thickening with involvement of vasculo-nervous structures in the tip of the cerebellum, cavernous sinus, ragged foramen, and optic chiasm. The patient presented for consultation with the result of an incisional biopsy that reported a proliferative lesion combining fibrous elements of fascicular or swirling arrangement with collagenized streaks with dense, lymphoplasmacytic infiltrate and some macrophages, with negative staining for ALK 1, with a diagnosis of inflammatory myofibroblastic tumour. Due to suspicion of IgG4-related disease (IgG4-RD) the biopsy was sent for review and pertinent complementary studies were requested.

BIOPSY REVIEW

Non storiform fibrosis, predominantly lymphoplasmacytic infiltrate, histiocytes, and polymorphonuclear infiltrate in sectors, without granulomas or atypia. Staining for germs negative. Immunohistochemistry with 50-60 IgG4+/HPF cells and range of 15%-20%, CD68⁺ in histiocytes, CD1a^-, S100^-. The patient presented deterioration of visual acuity due to ophthalmic nerve involvement, so glucocorticoid treatment was started in pulses and rituximab with regression of symptoms and imaging improvement of the lesions.

CONCLUSION

HP is a clinical imaging syndrome with variable symptoms and aetiologies that poses a diagnostic challenge. In this case the initial diagnosis was inflammatory myofibroblastic tumour, which is a neoplasm of variable behaviour, locally aggressive, and can metastasize; it is one of the main differential diagnoses of IgG4-related disease because they share anatomopathological features, including storiform fibrosis. IgG4-RD is an immune-mediated condition that can have single or multiple involvement. Its diagnosis is complex when it presents with single organ involvement or in non-typical organs (CNS, meninges) in which data are scarce, as in the case of our patient with single organ involvement of the CNS. Although there are classification criteria to guide non-specialists in the diagnosis, the sum of the clinical picture, imaging, laboratory, pathological anatomy, and immunohistochemistry will always be evaluated together for a definitive diagnosis.

Case report: Clinical highlights and radiological classification of IgG4-related spinal pachymeningitis: A rare case series and updated review of the literature

Purpose

Hypertrophic pachymeningitis associated with immunoglobulin G4-related disease (IgG4-RD) has been rarely reported, and there is little information and no clear consensus on the management of IgG4-related spinal pachymeningitis (IgG4-RSP). The present study described its possible clinical features, including the symptoms, imaging, treatment and prognosis of patients with IgG4-RSP.

Methods

We report three patients who presented with progressive neurological dysfunction due to spinal cord compression. Relevant articles were searched from the PubMed, Web of Science, and Embase databases, and the resulting literature was reviewed.

Results

The literature review provided a summary of 45 available cases, which included three cases from our center. Progressive worsening of neurological impairment was observed in 22 patients (48.9%). The lesions involved the thoracic spine (n=28, 62.2%), cervical spine (n=26, 57.8%), lumbar spine (n=9, 20.0%), and sacral spine (n=1, 2.2%). Furthermore, the lesions were located in the dura mater (n=18, 40.0%), epidural space (n=17, 37.8%), intradural-extramedullary space (n=9, 20.0%), and intramedullary space (n=1, 2.2%). On magnetic resonance imaging (MRI), the lesions generally appeared as striated, fusiform, or less often lobulated oval changes, with homogeneous (n=17,44.7%) and dorsal (n=15,39.5%) patterns being the most common. Thirty-five patients had homogeneous T1 gadolinium enhancement. Early surgical decompression, corticosteroid treatment, and steroid-sparing agents offered significant therapeutic advantages. A good therapeutic response to disease recurrence was observed with the medication.

Conclusion

The number of reported cases of IgG4-RSP remains limited, and patients often have progressive worsening of their neurological symptoms. The features of masses identified on the MRI should be considered. The prognosis was better with decompression surgery combined with immunosuppressive therapy. Long-term corticosteroid treatment and steroid-sparing agent maintenance therapy should be ensured. A systemic examination is recommended to identify the presence of other pathologies.

Angiomatous meningioma associated with rapidly aggravated peritumoral leptomeningitis: A case report

Background

A special type of meningioma is known to have infiltrated inflammatory cells within the tumor, associated with peritumoral inflammation. However, there have been no reports of meningioma with inflammatory response only around the tumor, without inflammatory cells within the tumor itself.

Case Description

A 70-year-old woman presented with transient right hemiparesis due to an extra-axial tumor on the left frontal convexity. The tumor appeared hypointense on T1-weighted magnetic resonance images and hyperintense on T2-weighted images without peritumoral edema, and was homogenously enhanced associated with the peritumoral leptomeningeal enhancement. Cerebrospinal fluid examination showed an increase in the number of inflammatory cells with a predominance of mononuclear cells. During the following 1 month, the tumor size was unchanged, but the peritumoral leptomeningeal enhancement was remarkably enlarged with uncontrolled focal seizures. The tumor was subtotally removed and semisolid substances in the subarachnoid space were biopsied. Pathological examination with immunostaining revealed angiomatous meningioma: the tumor had no inflammatory cell infiltration within it, but was associated with the infiltration of immunoglobulin G4-negative lymphocytes into the border zone between the tumor and the dura mater, as well as numerous neutrophils and fibrinous exudates in the peritumoral subarachnoid space. The tumor removal rapidly improved the leptomeningeal enhancement and inflammatory reactions.

Conclusion

The authors reported the first case of angiomatous meningioma associated with massive peritumoral inflammation without inflammatory infiltrates within the tumor itself.

A unique case of isolated thoracic spinal Rosai-Dorfman disease related to IgG4

Rosai-Dorfman disease (RDD) is a rare benign histiocytosis usually characterized by massive cervical lymphadenopathy and systemic manifestations. Extranodal, especially spinal involvement, is extremely rare. Our case was deemed worthy of presentation because it was the first reported isolated case of spinal RDD related to IgG4 and mimicked meningioma clinically and radiologically. A case with an intradural extramedullary mass causing neurological compression findings in the thoracic spinal region and radiologically mimicking meningioma is presented. In the histomorphological examination of the resection material, polymorphonuclear leukocytes in the dura, histiocytes showing emperipolesis, an increase in collagenized fibrous connective tissue, and intense lymphoplasmacytic cell infiltration accompanied by obliterative phlebitis were observed. Immunohistochemically, the histiocytic cells were found to be S-100 protein, CD68, and CD163 positive and CD1a and langerin negative, and more than half of the plasma cells were immunoglobulin-G4 (IgG4) positive. Although rare, RDD or IgG4-related meningeal disease should be considered in the differential diagnosis of dural-based spinal masses that radiologically suggest meningioma. The pathologist should be aware that these two histopathological entities may coexist. To our knowledge, this is the first case of "isolated spinal RDD related to IgG4" reported in the literature.

The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis)

BACKGROUND & IMPORTANCE

This patient and public-involved systematic review originally focused on arachnoiditis, a supposedly rare "iatrogenic chronic meningitis" causing permanent neurologic damage and intractable pain. We sought to prove disease existence, causation, symptoms, and inform future directions. After 63 terms for the same pathology were found, the study was renamed Diseases of the Leptomeninges (DLMs). We present results that nullify traditional clinical thinking about DLMs, answer study questions, and create a unified path forward.

METHODS

The prospective PRISMA protocol is published at Arcsology.org. We used four platforms, 10 sources, extraction software, and critical review with ≥2 researchers at each phase. All human sources to 12/6/2020 were eligible for qualitative synthesis utilizing R. Weekly updates since cutoff strengthen conclusions.

RESULTS

Included were 887/14286 sources containing 12721 DLMs patients. Pathology involves the subarachnoid space (SAS) and pia. DLMs occurred in all countries as a contributor to the top 10 causes of disability-adjusted life years lost, with communicable diseases (CDs) predominating. In the USA, the ratio of CDs to iatrogenic causes is 2.4:1, contradicting arachnoiditis literature. Spinal fusion surgery comprised 54.7% of the iatrogenic category, with rhBMP-2 resulting in 2.4x more DLMs than no use (p<0.0001). Spinal injections and neuraxial anesthesia procedures cause 1.1%, and 0.2% permanent DLMs, respectively. Syringomyelia, hydrocephalus, and arachnoid cysts are complications caused by blocked CSF flow. CNS neuron death occurs due to insufficient arterial supply from compromised vasculature and nerves traversing the SAS. Contrast MRI is currently the diagnostic test of choice. Lack of radiologist recognition is problematic.

DISCUSSION & CONCLUSION

DLMs are common. The LM clinically functions as an organ with critical CNS-sustaining roles involving the SAS-pia structure, enclosed cells, lymphatics, and biologic pathways. Cases involve all specialties. Causes are numerous, symptoms predictable, and outcomes dependent on time to treatment and extent of residual SAS damage. An international disease classification and possible treatment trials are proposed.

[A case of IgG4-related disease exclusively affecting pia matter and cerebral parenchyma]

A 61-year-old man presented with slowly progressive cognitive decline. Brain MRI revealed left frontal lobe lesions with gadolinium enhancement along pia mater. Brain biopsy was performed and histopathological findings was compatible with the diagnosis of IgG4-related disease (IgG4-RD). Serum IgG4 level was within a normal range, and no other systemic organs were suggested to be involved by clinical symptoms or laboratory findings. Intravenous methylprednisolone therapy followed by oral prednisone induction markedly improved the cognitive functions and MRI findings detected at the initial diagnosis. Our case highlights the importance of including IgG4-RD as one of the differential diagnosis when encountering the patients suffering from isolated cranial lesions even in the absence of normal serum IgG4 level.

Refractory IgG4-related disease complicated with organising pneumonia and hypertrophic pachymeningitis

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) involves multiple organs, including the lungs and central nervous system. Lung lesions are frequently reported as mass lesions or non-specific interstitial pneumonia, whereas organising pneumonia (OP) due to IgG4-RD is rare. Furthermore, limited information is currently available on hypertrophic pachymeningitis (HP). We herein report a case of IgG4-RD complicated with OP and HP. The diagnosis was confirmed based on the serum concentration of IgG4 and the results of salivary gland and transbronchial lung biopsies. HP did not respond to steroid monotherapy and was also resistant to rituximab and intravenous cyclophosphamide; however, the combination therapy of methotrexate and dexamethasone was effective.

Immunoglobulin G4-related disease presenting as an intracranial mass extended from the infratemporal fossa

Background

Neurological manifestations in immunoglobulin G4-related diseases (IgG4-RD) are rare and documented in <2% of cases. It commonly involves pachymeninges forming hypertrophic pachymeningitis and rarely forms tumor-like masses.

Case Description

We present our experience with a biopsy-proven case of IgG4-RD presenting with an intracranial extradural tumor-like mass infiltrating the temporal lobe. The patient was treated with high doses of corticosteroids followed by slow tapering. The neurological manifestations gradually improved and resolved after 2 months with a cerebral MRI showing a significant reduction in the tumoral size.

Conclusion

When it comes to intracranial mass, IgG4-RD neuropathy is one of the rarest differential diagnoses for the central nervous system tumors. Early recognition of IgG4-RD and appropriate establishment of its long-term treatment may avoid unnecessary investigations and morbidity.

The great imposter: A case report of IgG4‐RD hypertrophic pachymeningitis with skull lytic lesion and pulmonary nodules

Immunoglobulin G4‐related disease (Ig4RD) is an inflammatory condition with unique clinical, serological, and pathological features. In this study, we report a challenging diagnostic clinical case of Ig4RD diagnosed based on histopathology. This unique imitating nature reinforces that it is crucial to consider the diagnosis of IgG4‐RD in those presenting with pachymeningitis.

IgG4-related hypertrophic pachymeningitis with tumor-like intracranial and intracerebral lesions

OBJECTIVE

IgG4-related hypertrophic pachymeningitis is a rare fibroinflammatory disorder that may cause localized or diffused thickening of the dura mater. Misinterpretations of the clinical and imaging findings are common. Clinical manifestations depend on the location of the inflammatory lesion and on compression of neural structures leading to functional deficits. A dural biopsy is commonly needed for a definitive diagnosis. Immunomodulatory therapy is considered the therapy of choice.

METHODS

Four patients with IgG4-related hypertrophic pachymeningitis were identified over a 5-year period. Patient-related characteristics including age, preoperative workup, signs and symptoms of patients, and diagnostic procedures were evaluated. Furthermore, the surgical treatment and 5-year follow-up outcomes were analyzed.

RESULTS

There were two adults and two adolescents (mean age 32 years; range 15 to 67 years). Two patients were male, and two were female. No history of disease was known in any of the patients. Clinical symptoms were epilepsy (n = 2), ataxia and nausea (n = 1), and facial nerve palsy (n = 1). MR imaging studies showed contrast enhancing lesions in the temporal region in two patients, and in the cerebellar region in the other two patients. Subtotal resection was performed in two instances and a biopsy via a suboccipital retrosigmoid approach was obtained in the other two patients. Histochemical and immunohistochemical investigations revealed an IgG 4 disease in all of these patients. Immunomodulatorry therapy led to clinical stability during follow-up of 5 years in all four cases.

CONCLUSION

The diagnosis of IgG4-related hypertrophic pachymeningitis is challenging, but is of great relevance as treatment differs significantly from other forms of pachymeningitis and a specific therapeutic approach may avoid long-term neurological complications. Our series contributes to a better clinical characterization of this rare disease.

[Recurrent myelitis in a case of IgG4-related respiratory disease]

We report an 80-year-old man with IgG4-related pleuritis who had been treated with a low dose oral steroid for two years and developed recurrent myelitis. He was admitted to our hospital with gradually worsening numbness in the lower body and difficulty in walking due to mild weakness and loss of proprioception in the legs. T₂-weighted MR images of the spinal cord showed a high signal intensity lesion, located centrally in the spinal cord at the Th2-4 spine levels. Laboratory data revealed an elevated serum IgG4 level and cerebrospinal fluid protein level. Anti-aquaporin 4 antibody, anti-myelin oligodendrocyte glycoprotein antibody and other autoantibodies were negative. He showed a good response to the administration of steroid pulse therapy with almost resolution of the neurological symptoms and MRI findings. He was followed with the maintenance therapy with a low dose oral steroid. After one year, he developed recurrence of myelitis in the lower end of the medulla oblongata and in the central to dorsal area at the C2 spine level. Each lesion of recurrent myelitis was located within 3 vertebral segments length and improved without focal spinal atrophy. Recently, IgG4-related disease (IgG4-RD)-associated inflammation involving brain parenchyma and spinal cord were reported. Further investigations are needed to elucidate the relationship between IgG4-RD and seronegative recurrent myelitis.

Intracranial Tumors Associated With IgG4-Related Disease

IgG4-related disease (IgG4-RD) is an immune-mediated inflammatory condition which is characterized by dense lymphoplasmacytic infiltrations with a predominance of IgG4 plasma cells in the affected tissue. Although pachymeninx and pituitary gland are the most common sites where IgG4-RD infiltrates, the associations with IgG4-RD and a true intracranial tumor have not been yet reported in literature. Herein, we report two cases with intracranial tumors associated with IgG4-RD; a 36-year-old male patient with a huge meningioma and another 54-year old woman with a pituitary macroadenoma. Pathological examination revealed their tumors were substantially infiltrated by IgG4 plasma cells indicating its possible relation with IgG4-RD.

Hypertrophic pachymeningitis in polyarteritis nodosa: a case-based review

Hypertrophic pachymeningitis (HP) is a rare neurological disorder with focal or diffuse thickening of the dura mater, which usually causes headache, cranial neuropathies, seizures, and motor or sensory impairments. The development of HP is attributed to an immune-mediated mechanism, and some autoimmune diseases have been implicated in the development of HP. Herein, we describe the case of a 73-year-old woman with persistent headache ascribable to HP, which developed approximately 3 years after a diagnosis of polyarteritis nodosa (PAN). She was treated with high-dose corticosteroid and cyclophosphamide that resulted in immediate disappearance of headache and improved radiological findings of thickened dura mater. In addition, she was subsequently administered methotrexate, ultimately resulting in maintenance of remission and regular reduction of prednisolone. In our review of published English articles, only two cases of HP in patients with PAN have been reported to date, suggesting that HP is a rare complication in PAN. However, it should be recognized that HP may develop as a neurological involvement related to PAN.

Sellar Tumors

Sellar region lesions include a broad range of benign and malignant neoplastic as well as non-neoplastic entities, many of which are newly described or have recently revised nomenclature. In contrast to other intracranial sites, imaging features are relatively less specific, and the need for histopathological diagnosis is of paramount importance. This review will describe pituitary adenomas, inflammatory lesions, and tumors unique to the region (craniopharyngioma) as well as tumors which may occur in but are not exclusively localized to the sellar location (schwannoma, metastasis, etc.).

IgG4-Related Disease of the Skull and Skull Base-A Systematic Review and Report of Two Cases

OBJECTIVE

IgG4-related disease (IgG4-RD) is an inflammatory process that uncommonly can present in the skull base and calvarium and mimic a tumor but the nature of this condition is not well summarized in the neurosurgical literature.

METHODS

A review was performed of 2 cases of IgG4-RD in the skull base highlighting the diagnostic challenges with assessment of these skull base lesions, and a systematic review of relevant literature was carried out.

RESULTS

A systematic review of the literature conducted in accordance with PRISMA guidelines identified 113 articles, with 184 cases of IgG4-RD in the skull base or calvarium. The most commonly affected locations include the meninges, cavernous sinus, base of the posterior fossa, clivus, and mastoid bone. Headache, visual and auditory disturbances, cranial nerve dysfunction, and seizures were the most common presenting symptoms. Medical treatment was highly successful and most commonly consisted of corticosteroids coadministered with immunosuppressive agents such as rituximab. Prevalence seemed to be equal between sexes, and serum IgG4 levels were increased in 61% of patients. Delayed diagnosis and a need for multiple biopsies were reported in numerous cases. Two cases of skull base IgG4-RD from the authors' institution show the variable presentations of this disease. More invasive surgical biopsies were required in both cases, and corticosteroid treatment led to significant clinical improvement.

CONCLUSIONS

IgG4-RD is an uncommon condition with an increasing body of reported cases that can affect the skull base and calvarium and should be in the differential diagnosis, because delay in diagnosis and treatment may be common.

Meningioma: A Pathology Perspective

Meningiomas are dural-based neoplasms that account for ∼37% of all intracranial tumors in the adult population. They can occur anywhere within the central nervous system and have a predilection for females. The World Health Organization classifies meningiomas into 3 grades based on increased risk of recurrence and associated mortality in grade III tumors. Although most tumors are categorized as low-grade, up to ∼15%-20% demonstrate more aggressive behavior. With the long-recognized association with neurofibromatosis type 2 gene mutation, putative driver mutations can be attributed to ∼80% of tumors. Several germline mutations have also been identified in some cases of familial meningiomatosis such as SMARCE1, SUFU, PTEN, and BAP1. Finally, in addition to genetic data, epigenetic alterations, specifically deoxyribonucleic acid methylation, are being increasingly recognized for their prognostic value, potentially adding objectivity to a currently subjective grading scheme.

The protean manifestations of central nervous system IgG4-related hypertrophic pachymeningitis: a report of two cases

Background

IgG4-related hypertrophic pachymeningitis is a relative newly recognized and rare manifestation of IgG4-related disease, an immune-mediated fibroinflammatory tumefactive disorder. Fewer than 80 patients have been reported in the literature, and it can mimic common neurosurgical conditions. We describe the clinical presentation of two patients that were initially considered to have a subdural collection, tuberculous meningitis, and a cervical spinal meningioma, but were eventually diagnosed with this disease.

Case presentation

Two ethnic Chinese men, 86 and 62 years old, experienced a 4-week history of headache. Both patients had a history of autoimmune disease, namely glomerulonephritis and Grave’s disease, respectively. Magnetic resonance brain imaging revealed diffuse dural thickening with the latter patient exhibiting homogeneous and intense gadolinium-contrast enhancement. Since the 86-year-old patient also had progressive bilateral visual loss, giant cell arteritis was suspected and a 2-week course of glucocorticoid therapy was prescribed, but his symptoms failed to improve. The 62-year-old patient also had accompanying low-grade fever and was treated empirically as having tuberculous meningitis although there were no confirmatory microbiological findings. This patient further developed right hemiparesis, and additional imaging revealed a C4/5 intradural-extramedullary contrast-enhancing lesion resembling a meningioma causing cord compression. Both patients underwent neurosurgical intervention with the former undergoing a dural biopsy and the latter having the cervical lesion resected. The final diagnosis was IgG4-related hypertrophic pachymeningitis with the hallmark histological features of lymphoplasmacytic infiltration of IgG4+ plasma cells, storiform fibrosis, and obliterative phlebitis. In addition, their serum IgG4 levels were elevated (i.e., > 135 mg/dL). Both patients received at least 6 months of glucocorticoid therapy while the latter also had azathioprine. Their symptoms improved significantly and recurrent lesions were not detected on follow-up imaging.

Conclusions

A high index of suspicion for this condition is suggested when a male patient with a history of autoimmune disease and compatible radiological findings, experiences subacute headache that is disproportionate to the degree of dural involvement. Neurosurgeons should consider early meningeal biopsy to establish a definitive histological diagnosis in order for early effective immunosuppressive treatment to be initiated and to avoid unnecessary morbidity.

IgG4-Related Inflammatory Pseudotumor Involving the Clivus: A Case Report and Literature Review

IgG4-related inflammatory pseudotumors are very uncommon and are characterized histologically by the presence of inflammatory swellings with increasing IgG4-positive plasma cells and lymphocytes infiltrating the tissues. As reports of intracranial IgG4-related pseudotumors are very rare, we report a case of an IgG4-related inflammatory pseudotumor involving the clivus mimicking meningioma. A 46-year-old male presented with intermittent headache for 2 years and a sudden onset of dysphagia and dysphonia of 7 days' duration along with lower limb weakness. Enhanced magnetic resonance imaging (MRI) of the skull base revealed an isointense signal on T1- and T2-weighted images from an enhanced mass located at the middle of the upper clivus region, for which a meningioma was highly suspected. Then, an endoscopic transsphenoidal approach was adopted and the lesion was partially resected, as the subdural extra-axial lesion was found to be very tough and firm, exhibiting fibrous scarring attaching to the brain stem and basal artery. After the surgery, brain stem and posterior cranial nerve decompression was achieved, and the patient's symptoms, such as dysphagia, dysphonia and lower limb weakness, improved. Pathological findings showed many IgG4-positive plasma cells and lymphocytes surrounded by collagen-rich fibers. The patient was sent to the rheumatology department for further glucocorticoids after the diagnosis of an IgG4-related inflammatory pseudotumor was made. This case highlights the importance of considering IgG4-related inflammatory pseudotumors as a differential diagnosis in patients with lesions involving the clivus presenting with a sudden onset of symptoms of dysphagia and dysphonia along with lower limb weakness when other more threatening causes have been excluded. IgG4-related inflammatory pseudotumors are etiologically enigmatic and unpredictable, and total resection might not be warranted. Glucocorticoids are usually the first line of treatment after diagnosis.

An Update on Idiopathic Hypertrophic Cranial Pachymeningitis for the Headache Practitioner

PURPOSE OF REVIEW

We aim to review idiopathic hypertrophic cranial pachymeninigitis (IHCP), describe common head pain patterns and features associated with the disorder, suggest potential classification of head pain syndromes based on the recently published International Classification of Headache Disorders-3, explore pathophysiology found to be associated with cases of IHCP, and indicate common treatment for the disorder.

RECENT FINDINGS

It is suggested that a subset of IHCP is an IgG4-related autoimmune disorder. Patients with IHCP were found to have elevated cerebrospinal fluid (CSF) protein and lymphocytic pleocytosis. Corticosteroids are a mainstay of treatment. Other immunosuppressive agents and steroid sparing agents as add-on therapy may have utility in the treatment of cases refractory to corticosteroids alone. Clinical manifestations of IHCP depend upon the location of the inflammatory lesions and compression of the adjacent nervous system structures. Headache and loss of cranial nerve function were the most common presenting features of hypertrophic cranial pachymeninigitis. Several headache diagnoses may result from IHCP. Gadolinium-enhanced MRI is the standard imaging modality for diagnosing. Although the pathophysiology is poorly understood, many cases of hypertrophic pachymeninigitis (HP) are thought to be closely related to inflammatory disorders. Cases of HP previously thought to be idiopathic may have IgG4 pathophysiology. CSF and serological studies are helpful. Treatment involves immunosuppressive agents. Advancement in neuroimaging, assays, tests, and further delineation of inflammatory disorders affecting the nervous system may provide further insight to the etiology of cases of HP previously considered and diagnosed as idiopathic.

Hypertrophic Pachymeningitis in Chinese Patients: Presentation, Radiological Findings, and Clinical Course

Background

Hypertrophic pachymeningitis (HP) is generally regarded as a rare inflammatory disease, which results in a diffuse thickening of the dura mater. We retrospectively collected data from patients with HP.

Methods

A total of 16 patients with HP were included in our study. The clinical features, laboratory evaluation, imaging findings, treatment, and outcome were reviewed.

Results

Of the 16 cases, half were male, with a mean age of 52.6 ± 13.2 years. The mean duration from onset to diagnosis was 8.6 months. The most frequent presenting symptoms in HP cases were a recurrently chronic headache (81.3%) and multiple cranial nerve injury (50%). Antineutrophil cytoplasmic antibody- (ANCA-) related HP was found in 5 cases and IgG4-related HP in 1 case. The intracranial pressure was elevated in 4 cases. The cerebrospinal fluid (CSF) had lymphocytosis in 5 cases and increased protein in 12 cases. Immunoglobulins (IgG, IgA, and IgM) and protein showed linear relationships in the CSF. On magnetic resonance imaging (MRI), localized or diffuse dura maters were thickened in all cases. HP combined with subacute subdural hemorrhage or hypertrophic spinal pachymeningitis was also observed in individual cases. Biopsy of the dura mater in one case showed amounts of inflammatory cells infiltrating, with an increased percentage of IgG4-positive plasma cells. Of all cases referring to glucocorticoid treatment, the symptoms have improved significantly in 10 cases. In other 6 cases, mycophenolate mofetil or azathioprine was added. All patients showed clinical improvement at the follow-up visits.

Conclusion

The clinical characters of HP are chronic onset, recurrently chronic headache, and multiple cranial nerves paralysis. Inflammatory changes in CSF caused by intrathecal synthesis of immunoglobulin, characteristic dural enhancement on MRI, and pathologic biopsy are all helpful for diagnosis. The addition of immunosuppressant, especially mycophenolate mofetil, is a good choice for steroid-resistance HP.

Immunoglobulin G4-Related Hypertrophic Pachymeningitis of the Spine: A Case Report and Systematic Review of the Literature

BACKGROUND

Spinal immunoglobulin G4-related hypertrophic pachymeningitis (IgG4-HP) is a rare disease. Little information is known regarding the diagnosis, management, and prognosis of patients with spinal IgG4-HP.

METHODS

The authors present a case of spinal IgG4-HP with a systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant studies (up to April 2020) that reported patients with spinal IgG4-HP, based on the criteria of Japan College of Rheumatology, were identified from the PubMed and Cochrane Library databases.

RESULTS

This systematic review identified 33 patients, including the present case, of whom 21 were male and 12 were female. The mean value of age was 51.2 (±12.6) years. Eight patients had systemic involvement. In addition, among 33 patients, 13 patients had an elevated serum IgG4. Surgery was performed in 31 patients. Steroid therapy alone and steroid therapy with immunosuppressants were effective in 94% and 100% of the cases, respectively. Furthermore, 31 of 33 patients reported improved outcomes, 1 patient died due to infection, and in 2 patients the data were not available.

CONCLUSIONS

Spinal IgG4-HP is a rare entity. In addition, it should be considered in the differential diagnosis of space-occupying lesions around the spinal cord. Histopathology with immunohistochemistry results provides the most reliable evidence for diagnosis. Steroid therapy is the first line of treatment. Surgical decompression may be required in patients presenting with nerve root and/or spinal cord compression. Long-term follow-up is necessary for patients with spinal IgG4-HP.

IgG4-Related Disease in the Frontal Convexity Concomitant with Smoldering Multiple Myeloma: A Case Report and Review of the Literature Regarding Therapeutic Implications

BACKGROUND

We have reported an extremely rare case of a frontal convexity tumor diagnosed as IgG4-related disease (IgG4-RD) with unique neuroradiological images.

CASE DESCRIPTION

A 64-year-old man with a history of monoclonal gammopathy of undetermined significance and conservative treatment had presented with a left facial spasm. Computed tomography showed a high-density round tumor with perifocal edema in the right frontal convexity. Magnetic resonance imaging demonstrated unique findings, including low signal intensity on T1- and T2-weighted, fluid-attenuated inversion recovery, and diffusion-weighted images, with slight gadolinium enhancement. The tumor was totally removed via right frontal craniotomy. It had been located in the subdural space, was not adherent to the dura, and was less vascular than meningiomas. Histological investigation demonstrated plasma cells that were strongly positive for IgG4 and contained κ and λ light chains at a ratio of 1.5:1. The serum IgG4 level was elevated. The tumor met the diagnostic criteria for IgG4-RD. The patient was followed up for 3 years during postoperative adjuvant steroid therapy. The steroid therapy was discontinued, and during the next 4 years, neither tumor recurrence nor symptoms were observed.

CONCLUSION

Intracranial IgG4-RD with smoldering monoclonal gammopathy of undetermined significance is extremely rare. We reviewed the differential diagnosis of plasma cell granuloma and plasmacytoma, therapeutic implications, and clinical outcomes. Complete resection of a conspicuous and solitary IgG4-RD lesion in the frontal convexity is simple and could provide a cure with less-aggressive adjuvant therapy.

[IgG4-related disease: Diagnostic criteria evolution toward the 2019 ACR/EULAR classification criteria]

The concept of IgG4-related disease (IgG4-RD) has recently been individualized in the early 2000s, but most of the organ involvements are known since more than 100 years. IgG4-RD is a non-malignant fibroinflammatory disorder, characterized by peculiar immunological and pathological abnormalities, which can affect virtually all organs or tissues. Diagnostic criteria have been proposed and have evolved rapidly, with general or organ specific criteria. An international and multidisciplinary group assembled by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) has recently developed and validated a set of classification criteria called 2019 ACR/EULAR classification criteria for IgG4-related disease. The objective of this review is to discuss the evolution from organ specific and general diagnostic criteria toward the 2019 ACR/EULAR classification criteria, as well as respective benefits and limits of these criteria. The use of the 2019 ACR/EULAR classification criteria will help to better define homogeneous group of IgG4-RD patients in future clinical, epidemiological and basic science research studies on the disease.

Clinicopathological differential diagnosis of IgG4-related disease: A historical overview and a proposal of the criteria for excluding mimickers of IgG4-related disease

IgG4-related disease (RD) is a relatively new entity, which was first proposed in 2001. Since then, clinical and pathological characteristics of the disease have been investigated. As IgG4-RD has been studied extensively, the diagnostic criteria for IgG4-RD of each organ and the comprehensive diagnostic criteria for IgG4-RD have also been developed. However, one of the biggest challenges in the field is distinguishing between IgG4-RD and mimickers, which show overlapping features with IgG4-RD. It is now known that some non-IgG4-RDs may meet the diagnostic criteria of IgG4-RD and can be misdiagnosed as IgG4-RD. However, accurate diagnosis is crucial, as the treatments for IgG4-RD and those for other diseases that may be misdiagnosed as IgG4-RD are different. This prompted us to create and propose comprehensive exclusion criteria for IgG4-RD. In this review, we have described the comprehensive exclusion criteria for IgG4-RD, with a historical overview of the disease. These exclusion criteria were recently created by the Research Program for Intractable Disease of the Ministry of Health, Labor, and Welfare of Japan, All Japan IgG4 team, to support correct and accurate diagnosis of IgG4-RD.

Intracranial Multiple Pseudotumor Due to Immunoglobulin G4-Related Disease without Other Lesions: Case Report and Literature Review

BACKGROUND

Immunoglobulin (Ig)G4-related disease (IgG4-RD) was defined only recently and can be found in many organs. As intracranial lesions, hypophysitis and pachymeningitis are well known, whereas intracranial pseudotumor is unusual. This case involved multiple intracranial pseudotumors without extracranial lesions, mimicking multiple meningioma.

CASE DESCRIPTION

A 72-year-old woman was referred to our hospital with an incidental mass lesion at the craniocervical junction on magnetic resonance imaging (MRI). MRI showed diffuse enhanced extra-axial nodules around the medulla and middle cranial fossa. Surgery was performed for the gradually enlarging tumor. Intraoperative findings showed hard nodules around the vertebral artery. We performed subtotal resection. Neuropathological findings showed diffuse lymphoplasmacytic infiltration with lymphoid follicles. Immunohistochemical studies for IgG4 and IgG showed the histological criteria for IgG4-RD were met. Given the high IgG4 serum level, we diagnosed IgG4-RD. Steroid was administered initially but was then tapered, and nodules have since remained small.

CONCLUSIONS

This case demonstrates IgG4-RD mimicking meningioma with multiple masses but without extracranial lesions. This case and previous descriptions suggest the possibility of pseudotumor due to IgG4-RD in the presence of multiple extra-axial lesions at the dura and supplying artery, hard nodules with thickening of the artery, and frozen section findings of lymphoplasmacytes surrounded by rich collagen fibers. In such cases, the pseudotumor due to IgG4-RD should be resected, and total resection might not be warranted.

First Report of IgG4 Related Disease Primary Presenting as Vertebral Bone Marrow Lesions

IgG4-related disease is a fibro-inflammatory disorder characterized by swelling of tissues and affected organs accompanied by the development of scar tissue (fibrosis) and infiltration by IgG4 positive plasma cells. Almost any organ can be affected, including, but rarely, bone marrowinvolvement. Here we present a case of a 76-year-old male with IgG4-related disease presenting primarily with vertebral bone marrow lesions. Histopathology showed the typical features of storiform fibrosis, and increased IgG4 positive plasma cells. Treatment with corticosteroids significantly improved wellbeing and resolved lesion size on MRI.

Rheumatoid Meningitis: Clinical Characteristics, Diagnostic Evaluation, and Treatment

Background and Purpose

Due to the potential for high mortality and neurologic complications of rheumatoid meningitis (RM), awaiting biopsy confirmation may delay vital treatment intervention. Our aim was to describe the clinical presentations of RM in our population and determine whether meningeal biopsy impacted diagnosis, treatment, and outcomes.

Methods

A retrospective chart review was completed for patients at Mayo Clinic with a diagnosis of RM within the last 28 years. Those with identified alternative inflammatory, infectious, or neoplastic causes of pachymeningitis or leptomeningitis were excluded.

Results

Fourteen patients meeting inclusion/exclusion criteria were identified. All patients were positive for rheumatoid factor or cyclic citrullinated peptide. All patients had magnetic resonance imaging abnormalities characterized by pachymeningeal and/or leptomeningeal enhancement. Of the 10 patients who underwent biopsy, nonspecific findings were seen in 74%. All patients except one were treated with corticosteroids with subsequent symptomatic improvement. Radiographic improvement or resolution was seen in 10 (83%) of 12. Patients improved with corticosteroid treatment, including those who were diagnosed with RM on clinical basis without undergoing a biopsy as well.

Conclusions

This retrospective review displays the myriad of clinical presentations of RM. It also suggests that with appropriate exclusion of infectious, neoplastic, and other autoimmune etiologies, biopsy may not be necessary to initiate treatment.

Immunoglobulin G4-related hypertrophic pachymeningitis: A case-oriented review

Objective

Meningeal involvement in Immunoglobulin G (IgG)-4-related disease is rare and only described in case reports and series. Because a review into the disease is lacking, we present 2 cases followed by a literature review of IgG4-related hypertrophic pachymeningitis (IgG4-HP).

Methods

Two IgG4-HP cases were reported, one involving the spinal cord and responding to surgical management and a second involving the brain and responding to Rituximab therapy. We then review clinical cases and case-series of histologically proven IgG4-HP that were published in the PubMed-NCBI database.

Results

Forty-two case reports and 5 case-series were studied (60 patients, 20 women). The median age was 53. Eighteen patients had systemic involvement and 24 had single-organ IgG4-HP. Fifty-five percent of patients had an elevated serum IgG4. Treatment was surgical in 20/53 cases. Steroid therapy and immunosuppressors were effective in 85% and more than 90% of the cases, respectively. The rate of disease relapse was 42.1% after steroid therapy was discontinued.

Discussion/conclusion

IgG4-HP is characterized by the lack of extra-neurologic organ-involvement and systemic signs. Histopathologic studies should be performed as it is crucial for diagnosis because serum markers are rarely informative. 18F-FDG positon tomography can be useful to characterize systemic forms. There is no specific CSF marker for IgG4-HP and the diagnostic value of CSF IgG4 levels needs to be studied with larger samples. We provide a treatment algorithm for IgG4-HP. Such treatment strategies rely on early surgery, steroids, and early immunosuppressive therapy to prevent neurologic complications.

Dural masses: meningiomas and their mimics

Meningiomas are the most common dural tumour. They are regularly being seen as an incidental finding on brain imaging and treated conservatively. However, there are many other dural masses which mimic their appearances, including primary neoplastic processes, metastases, granulomatous diseases and infection. While some of these are rare, others such as metastases and tuberculosis arise relatively frequently in practice. Although not pathognomonic, key features which increase the probability of a lesion being a meningioma include intralesional calcifications, skull hyperostosis, local dural enhancement and increased perfusion. It is important to have an awareness of these entities as well as their main imaging findings, as they have a wide range of prognoses and differing management strategies. This review outlines several of the most important mimics along with their imaging findings on both standard and advanced techniques with key features which may be used to help differentiate them from meningiomas.

IgG4-related disease of the central and peripheral nervous systems

IgG4-related disease can involve nearly any organ system, including the central and peripheral nervous systems. The pathology findings are consistent from organ to organ, but careful clinicopathological correlation is necessary to establish the diagnosis. Many non-neurological and neurological inflammatory conditions, previously regarded as idiopathic in nature, are now recognised to fall within the spectrum of IgG4-related disease. The condition is highly treatable, but probably remains substantially under-recognised. In this Review, we offer an important and timely update on the current and emerging aspects of this neurological disease. Following a short overview of IgG4-related disease, we describe the current understanding of neurological findings, pathophysiology, approaches to diagnosis, and treatment of IgG4-related disease affecting the central and peripheral nervous systems.

Hide and seek

A 51-year-old woman with a previous history of rheumatoid arthritis experienced painless progressive visual loss in the left eye for 3 weeks. Fundus examination revealed optic disk pallor in her left eye. Magnetic resonance imaging of the brain and orbits showed enhancement of the pachymeninges and hypersignal at the left optic nerve. Meningeal biopsy was performed. Immunohistochemical staining for IgG4 revealed several IgG4-positive plasma cells, which in some areas reached the number of 50 cells/high-power field. In this case, the clinical and histopathological features of the patient met diagnostic criteria for rheumatoid arthritis and IgG4-related disease, respectively. Rheumatoid arthritis sometimes occurs with abundant IgG4 plasma cells and fulfills the histological diagnostic criteria for IgG4-related disease. This case demonstrates that overlapping features of IgG4-RD and rheumatoid arthritis may present in a single patient.

Neuro-surgical considerations for treating IgG4-related disease with rare spinal epidural compression

Background:

Immunoglobulin G4-related disease (IgG4-RD) is a group of distinct autoimmune disorders affecting nearly every organ system in the body. Although central nervous system involvement is quite rare, it may present as hypertrophic pachymeningitis more frequently affecting the brain than the spine. In this study, we provide a case of spinal IgG4-RD pseudotumor resulting in cord compression, and a comprehensive review of the literature.

Case Description:

A patient presented with an extradural mass causing spinal cord compression at the L2-L3 level. Pathologically this proved to be an IgG4-RD pseudotumor. The patient was treated with thecal sac decompression and post-operative steroids that resulted in complete resolution of his symptoms.

Conclusion:

IgG4-RD is typically under-recognized and under-reported in the spinal literature. The clinical spinal presentation and non-surgical vs. surgical treatment are relatively straightforward. Although most cases can be managed with a course of steroids, surgical decompression may be required in patients presenting with spinal cord and/or nerve root compression. The differential diagnoses for these spinal tumors or pseudotumors should include IgG4-RD. Early detection and appropriate treatment can lead to satisfactory outcomes.

IgG4-related intracranial disease

IgG4-related disease (IgG4-RD) is a multi-organ chronic inflammatory process caused by infiltration of IgG4-positive plasma cells in one or more organs. Intracranial involvement has only recently become better recognized. Our case series adds to the growing literature on the varying presentations of intracranial IgG4 by describing the clinical and imaging findings of three patients who presented to our institution with intracranial involvement. Our first patient presented with a mass-forming IgG4 pachymeningitis mimicking a sphenoid wing meningioma, which is to our knowledge the largest mass-forming pachymeningitis published in the literature. Our second case depicts another presentation of extensive IgG4 pachymeningitis involving both cavernous sinuses and surrounding Meckel's caves. The third case describes a patient with presumed lymphocytic hypophysitis, which was later determined to be IgG4-related hypophysitis with concomitant pachymeningitis and perineural spread along the optic nerves. The delayed diagnoses in our cases illustrates the diagnostic challenge that clinicians face in differentiating intracranial IgG4-RD from other infiltrative diseases such as sarcoidosis, granulomatous disease, tuberculosis and lymphoma. Earlier consideration of IgG4-related hypophysitis and hypertrophic pachymeningitis in the differential diagnosis can prevent significant morbidity including unnecessary surgical intervention and organ failure secondary to extensive fibrosis.

Clivus Inflammatory Pseudotumor Associated with Immunoglobulin G4-Related Disease

BACKGROUND

Immunoglobulin G4 (IgG4)-related disease is a more recently recognized syndrome. It is characterized by increasing IgG4-positive plasma cells and lymphocyte infiltration. Reports of intracranial pseudotumors associated with IgG4-related disease are very rare. We report a rare case of clivus pseudotumor associated with IgG4-related disease mimicking meningioma.

CASE DESCRIPTION

A 50-year-old man presented with abducens paralysis of the right eye. Brain magnetic resonance imaging revealed a uniformly enhanced mass located in the right upper clivus area, and meningioma was highly suspected. The tumor was totally resected via a retrosigmoid approach craniotomy, which achieved sufficient decompression of the right abducens nerve. Postoperative pathology revealed IgG4-related disease with IgG4 strongly positive on immunohistochemical staining. The patient had no history of autoimmune disease. Postoperative laboratory data revealed no elevation of either IgG (6.94 g/L) or IgG4 (0.131 g/L). Follow-up contrast MRI showed the lesion had disappeared.

CONCLUSIONS

Although several cases of intrasellar hypophysitis have been reported, reports of intracranial pseudotumors associated with IgG4-related disease are rare. Special attention is required when the differential diagnosis includes meningioma. Preoperative diagnosis is very important because inflammatory pseudotumors associated with IgG4-related disease could be treated with steroid therapy, avoiding surgery.

Leptomeningeal form of Immunoglobulin G4-related hypertrophic meningitis with perivascular spread: a case report and review of the literature

Purpose

Immunoglobulin G4 (IgG4)-related disease represents a spectrum of fibro-inflammatory disorders that affects various organ systems, including the central nervous system.

Methods

Here we present the case of lgG4-related hypertrophic meningitis with exclusively leptomeningeal involvement and spread via perivascular spaces.

Results

A 58-year-old male patient presented with complex partial seizures. Initial computed tomography examination showed left frontal sulcal hyperdensity. Subsequent magnetic resonance examination revealed FLAIR hyperintensity in the central sulcus, with post-contrast enhancement in the form of “dotted line.” Physical examination, routine laboratory, and cerebrospinal fluid analyses were unremarkable. Meningeal biopsy confirmed IgG4-related meningitis. After corticosteroid treatment, a complete resolution of imaging findings was observed. Two months later, the patient presented with relapsing neurological symptoms and radiological findings in postcentral, precentral, and temporal sulci, resembling the form of “dotted line” contrast enhancement. In addition, linear intraparenchymal enhancement that followed perivascular spaces was seen in the left parietal lobe. After repeated steroid therapy, all lesions resolved completely.

Conclusion

We reported the first case of isolated IgG4-related leptomeningeal involvement with a “dotted line” enhancement and perivascular intraparenchymal spread. Although IgG4-related meningitis represents a rare disease, both clinicians and radiologists should include this condition in the differential diagnosis of unclear leptomeningeal disease.

IgG4-related Disease - A Systemic Disease that Deserves Attention Regardless of One's Subspecialty

IgG4-related disease (IgG4-RD) is an inflammatory condition characterized by a high serum IgG4 concentration and the abundant infiltration of lymphocytes and IgG4-positive plasma cells in the tissue, as well as spatial (diverse clinical manifestations) and temporal (the possibility of recurrence) multiplicities. Since the initial documentation of IgG4-related disease in patients with autoimmune pancreatitis in 2001, a growing body of evidence has been accumulating to suggest that various-virtually all-organs can be affected by IgG4-RD. In general, steroid therapy is effective and is considered to be the first-line treatment for IgG4-RD. The precise mechanism underlying this systemic disorder has remained unknown. Considering that IgG4-RD was specified as being an intractable disease in 2015, further studies are needed to clarify whether IgG4-RD is indeed a distinct disease entity or a complex of disorders of different etiologies and clinical conditions.