Idiopathic hypertrophic pachymeningitis

Hypertrophic Pachymeningitis: An Unusual Cause of Headache

Hypertrophic pachymeningitis (HP) is a rare condition characterized by inflammation and thickening of the dura mater. It can be idiopathic or secondary to various causes, including infections, tumors, or systemic inflammatory diseases. Diagnosis is challenging due to its rarity and the overlap of symptoms with other conditions. We present the case of a 42-year-old Hispanic woman with diabetes mellitus type 2 and end-stage kidney disease who presented with chest pain, dry cough, mild dyspnea, and chronic occipital headaches. Physical examination revealed cranial VI nerve palsy. Imaging showed pulmonary cavitary lesions and mediastinal lymphadenopathy. Elevated inflammatory markers and positive autoimmune tests, including rheumatoid factor and antineutrophil cytoplasmic antibody (ANCA), led to further investigation. Brain imaging revealed dural thickening, confirming HP. The patient's medical history revealed double ANCA positivity and a lung biopsy confirmed granulomatous pneumonitis. A diagnosis of ANCA-associated vasculitis (granulomatosis with polyangiitis (GPA)) was established, and treatment with rituximab and high-dose corticosteroids led to symptom improvement. GPA rarely involves meningeal inflammation, but severe and persistent headaches are common early symptoms. Inflammatory markers are often elevated, and around two-thirds of HP cases related to GPA have positive serum ANCA. MRI is the primary diagnostic tool, with characteristic findings of dural thickening and contrast enhancement. This case highlights HP as a rare cause of chronic headaches and the importance of a comprehensive medical history in diagnosis. Early recognition and treatment are crucial for improving outcomes in GPA-related HP.

[Idiopathic hypertrophic pachymeningitis]

The article presents a case of idiopathic hypertrophic pachymeningitis of a 61-year-old male patient with severe cephalgia and progressive neuropathy of the oculomotor nerves. The diagnosis was confirmed by MRI with gadolinium, which revealed thickening of the dura mater with accumulation of paramagnetic in the convexital parts of the frontal and temporal regions, as well as on the base of the skull and tentorium. During the use of pulse therapy with glucocorticosteroids (GCS) the symptoms regressed, but when the therapy was stopped, there was a relapse of ptosis and oculomotor abnormalities on the other side followed by a slower effect of GCS therapy. The article also presents a brief review of current knowledge about this pathology.

Quantitative evaluation of the thickened dura mater impacting clinical signs in immune-mediated hypertrophic pachymeningitis

OBJECTIVE

This study evaluated the volume of thickened dura mater lesions and their impact on clinical findings in immune-mediated hypertrophic pachymeningitis (HP).

METHODS

The volume of contrast-enhanced dura mater on magnetic resonance imaging was evaluated using the imaging feature quantification system in 19 patients with immune-mediated HP, including 12 with antineutrophil cytoplasmic antibody-related, 4 with IgG4-related, and 3 with idiopathic HP, as well as 10 with multiple sclerosis (MS) as controls. The implications of HP volume on neurological manifestations and cerebrospinal fluid (CSF) laboratory markers were statistically analyzed in patients with immune-mediated HP.

RESULTS

The volumes of the contrast-enhanced dura mater in the convexity, cranial fossa, and tentorium cerebelli were significantly higher in patients with immune-mediated HP than in those with MS. Among patients with immune-mediated HP, those with cranial nerve (CN) VIII neuropathy had a significantly higher volume of the contrast-enhanced dura mater in the cranial fossa than those without CN VIII neuropathy. The volume of the contrast-enhanced dura mater in the tentorium cerebelli was positively correlated with CSF protein levels.

CONCLUSION

Quantification of the thickened dura mater is useful for elucidating the relationship with the clinical findings in immune-mediated HP. Thickened dura mater lesions in the cranial fossa may be implicated in the development of CN VIII neuropathy. The enlargement of HP lesions in the tentorium cerebelli can increase CSF protein levels.

Idiopathic hypertrophic pachymeningitis in a patient with a history of diffuse large B cell lymphoma

A man in his early 70s with a 4-year history of diffuse large B cell lymphoma (DLBCL) was admitted to our hospital with diplopia and achromatopsia. Neurological examination revealed visual impairment, ocular motility disorder and diplopia on looking to the left. Blood and cerebrospinal fluid investigations showed no significant findings. MRI revealed diffusely thickened dura mater and contrast-enhanced structures in the left apical orbit, consistent with hypertrophic pachymeningitis (HP). We performed an open dural biopsy to distinguish the diagnosis from lymphoma. The pathological diagnosis was idiopathic HP, and DLBCL recurrence was ruled out. Following methylprednisolone pulse and oral prednisolone therapy, his neurological abnormalities gradually receded. Open dural biopsy played an important role not only in diagnosing idiopathic HP but also in relieving the pressure on the optic nerve.

Hypertrophic pachymeningitis in ANCA-associated vasculitis: Clinical and immunopathological features and insights

Hypertrophic pachymeningitis (HP) is an inflammatory disorder characterized by intracranial and spinal thickened dura mater, leading to several neurological manifestations including headaches, cranial neuropathies, seizures, and sensorimotor disorders. Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a crucial disease that is implicated in the development of immune-mediated HP. HP is observed throughout the clinical course of AAV, and 3%-4% of patients with AAV experience HP as the initial clinical episode. However, patients with ANCA-related HP are unclassifiable in the classification criteria of AAV when HP is the only manifestation, suggesting that ANCA-related HP can be identified as a central nervous system-limited type of AAV. Among patients with AAV, those who develop HP have predominantly been classified as having granulomatosis with polyangiitis (GPA). Myeloperoxidase-ANCA positivity has been more frequently demonstrated than proteinase 3-ANCA positivity in patients with ANCA-related HP. The ear, nose, and throat manifestations, such as otitis media, sinusitis, and mastoiditis, as well as mucous membranes/eyes manifestations including sudden visual loss, are robustly associated with HP in AAV. The histology of thickened dura mater tissues includes fibrotic changes and infiltration of several immunocompetent cells, but the typical findings of GPA, such as granulomatous inflammation with necrotizing vasculitis, are not observed in all patients with ANCA-related HP. Corticosteroids are the first-line therapy for ANCA-related HP, while the concomitant use of immunosuppressive agents including cyclophosphamide, methotrexate, and mycophenolate mofetil, is an ideal strategy for achieving remission. Rituximab is a useful agent in refractory ANCA-related HP.

Comparison of the Morphologic and Mechanical Features of Human Cranial Dura and Other Graft Materials Used for Duraplasty

OBJECTIVE

This study aimed to compare the thickness and mechanical properties of the frontal; parietal; temporal; occipital human dura; autogenous grafts (facia lata, temporal fascia, galea aponeurotica); and artificial dura.

METHODS

Sagittal and transverse dura samples were obtained from standard regions of the cranial dura from 30 autopsies for histologic and mechanical property measurements. Identical measurements were made for the autogenous grafts artificial dura, and the results were statistically analyzed.

RESULTS

The thickness of the temporal (0.35 ± 0.11 mm), parietal (0.44 ± 0.13 mm), frontal (0.38 ± 0.12 mm), and occipital (0.46 ± 0.18 mm) dura showed regional variations. The parietal and occipital dura were significantly thicker than the temporal dura. The occipital dura was considerably thicker than the frontal dura. The frontal and temporal dura of males were significantly thicker than females. The sagittal maximum tensile force measurements were significantly greater than transverse, for the frontal, temporal, and occipital dura. The stiffness measurements in sagittal direction were greater than the measurements in transverse direction for the frontal dura. The mechanical properties and thickness of the autogenous and artificial dura were not similar to the human dura.

CONCLUSIONS

The thickness and mechanical properties of the regional cranial dura should be taken into consideration for a better cure and fewer complications. The mechanical properties of sagittal and transverse dura should be kept in mind for the preference of dura material. The present study's data can pave the way to produce artificial regional dura by mimicking the thickness and mechanical properties of the human dura.

A case of idiopathic hypertrophic pachymeningitis with high adenosine deaminase in cerebrospinal fluid

Adenosine deaminase (ADA) in cerebrospinal fluid (CSF) has been reported as useful to diagnose tuberculous meningitis and hypertrophic pachymeningitis (HP). The case of a 59-year-old woman with impaired vision and an auditory disturbance due to massive intracranial HP is presented. Although acid-fast bacillus cultures and polymerase chain reaction tests for Mycobacterium tuberculosis in the CSF were negative, tuberculous HP was diagnosed clinically because of the high ADA in CSF, and anti-tuberculosis drugs were administered with prednisolone because idiopathic HP (IHP) could not be ruled out. Since the impaired vision worsened with prednisolone reduction despite the continuation of anti-tuberculosis drugs, a dural biopsy was performed, and the patient was diagnosed with IHP. ADA is associated with lymphocyte proliferation and differentiation and increased by activation of cell-mediated immunity. Elevated CSF-ADA might be caused by lymphocyte infiltration in the thickened dura mater.

Hypertrophic cranial pachymeningitis and orbital apex syndrome secondary to infection of the eye: illustrative case

BACKGROUND

Hypertrophic cranial pachymeningitis is a rare inflammatory disorder characterized by thickening of the dura mater and multiple cranial neuropathies. Although an infectious etiology may be present, often no specific cause is discovered.

OBSERVATIONS

The authors described a 71-year-old man with progressive right eye vision loss, ptosis, and complete ophthalmoplegia with imaging findings suggestive of hypertrophic cranial pachymeningitis. Extensive studies, including cerebrospinal fluid studies, showed negative results. Blood serum, cell-free evaluation, and paraffin-embedded dural tissue testing had positive results for Pseudomonas aeruginosa, which allowed treatment tailored to the organism and a salutary clinical outcome.

LESSONS

The constellation of neurological and radiological findings may make a diagnosis difficult in an inflammatory setting. The most precise methodology for establishing a diagnosis involves sampling the dura and testing it for infectious pathology. However, if results are inconclusive, further cell-free serum sampling with next-generation sequencing is a viable option for identifying pathogens with infectious concerns. This case highlighted the importance of multimodality studies for identifying a targetable pathogen.

Idiopathic Hypertrophic Pachymeningitis: Does Earlier Treatment Improve Outcome?

Background/goal: Hypertrophic pachymeningitis is a rare chronic inflammatory disorder characterized by marked fibrous thickening of the cerebral and/or spinal dura mater. This condition has largely been reported in adults, but there are very few reports in children. Methods: We describe a 14-year-old boy with idiopathic hypertrophic pachymeningitis, who presented with deteriorating vision on a background of severe headache. We evaluated pediatric cases of hypertrophic pachymeningitis and compared treatments and their relation to outcomes. Results: There are only eleven pediatric cases of hypertrophic pachymeningitis reported in the literature. In the patients treated with steroids either at presentation or subsequent relapses, a good response was reported. In the cases with delayed initiation of steroid treatment, this was often related to an incomplete recovery. In our patient, this delay may have contributed to his poor visual outcome. Conclusions: Early initiation of steroid treatment in children with idiopathic hypertrophic pachymeningitis may improve outcomes.

Hypertrophic Pachymeningitis in a Southern Chinese Population: A Retrospective Study

Aims: To investigate the causes, clinical characteristics, imaging features, and therapeutic implications of hypertrophic pachymeningitis (HP) in a southern Chinese population.

Methods: We retrospectively analyzed 48 patients with HP with different causes from 1 January 2006 to 31 December 2018. Clinical manifestation, laboratory findings, and neuroimaging results were evaluated in all HP patients.

Results: The mean age at onset was 50 ± 12 years. The most common diagnosis was idiopathic HP (67%), followed by antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (15%), tuberculous meningitis (8%), viral meningitis (6%), and bacterial meningitis (4%). Headache was the most common symptom. The most frequently changed laboratory finding was elevated erythrocyte sedimentation rate (ESR). Imaging was characterized by cerebral or spinal dura mater enhancement in MRI scan with contrast. Enhancements were mainly located in the posterior fossa for idiopathic HP; frontal, parietal, and occipital lobes for ANCA-related HP; and posterior fossa for tuberculous-associated HP. Diffuse enhancement was found in most cases, except for tuberculous-associated HP. Glucocorticoid or immunosuppressive treatment was applied in most cases.

Conclusions: The etiology of HP varied among patients, with idiopathic HP being the most common. MRI showed enhancement of the dura mater, which differed according to different etiologies. Glucocorticoid or immunosuppressive agents were the primary drugs for treatment.

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.

Cerebrospinal fluid biomarkers implicated in the pathogenesis of anti-neutrophil cytoplasmic antibody-related hypertrophic pachymeningitis

OBJECTIVE

Hypertrophic pachymeningitis (HP) related to anti-neutrophil cytoplasmic antibody (ANCA) is the most frequently seen immune-mediated HP. We investigated cerebrospinal fluid (CSF) biomarkers related to the pathogenesis of ANCA-related HP (ANCA-HP).

METHODS

The levels of B cell activation factor of the tumor necrosis factor family (BAFF), a proliferation-inducing ligand (APRIL), and transforming growth factor beta 1 (TGF-β1) in the CSF were compared between patients with ANCA-HP (n = 12), other types of immune-mediated HP (other HP; n = 12), multiple sclerosis (MS; n = 14), and non-inflammatory neurological disorders (NIND; n = 10). In addition, we evaluated whether ANCA would be detected in CSF.

RESULTS

CSF levels of BAFF, APRIL, and TGF-β1 were significantly increased in ANCA-HP and other HP. In particular, BAFF and APRIL levels were significantly correlated with the IgG index in ANCA-HP. In other HP, BAFF and APRIL levels were significantly correlated with cell counts and protein levels in CSF. Of 12 patients with ANCA-HP, the CSF of 7 patients (58%) tested positive for myeloperoxidase (MPO)- or proteinase 3 (PR3)-ANCA, while none of the CSF samples from other HP, MS, or NIND patients tested positive.

CONCLUSION

The levels of BAFF, APRIL, and TGF-β1 may serve as useful CSF biomarkers for assessing the disease activity of immune-mediated HP. Moreover, BAFF and APRIL in the CSF may be implicated in the pathogenesis of ANCA-HP via promoting autoreactive B cells, while detecting MPO- or PR3-ANCA in the CSF may be found in some patients with ANCA-HP.Key Points• CSF BAFF, APRIL, and TGF-β1 levels increase significantly in immune-mediated HP.• CSF BAFF and APRIL levels are significantly correlated with IgG index in ANCA-HP.• Detection of MPO- or PR3-ANCA in the CSF is found in some patients with ANCA-HP.• BAFF, APRIL, and ANCA in the CSF may be implicated in the pathogenesis of ANCA-HP.

Distinguishing magnetic resonance imaging features between idiopathic hypertrophic pachymeningitis and secondary hypertrophic pachymeningitis

Background

Hypertrophic pachymeningitis (HP) is a rare chronic inflammatory disorder characterized by marked fibrous thickening of the cerebral and/or spinal dura mater. This condition is caused by infection, inflammation, autoimmune disorder, neoplasms, or idiopathic. Magnetic resonance imaging (MRI) may play an important role in differentiating idiopathic HP from secondary HP, may avoid unnecessarily invasive dural biopsy, and prompt specific treatment.

Objective

To determine the specific MRI findings for differentiation between idiopathic HP and secondary HP.

Method

A total of 34 patients underwent MRI of the brain and cervical spine from January 2003 to December 2015. In all, 23 patients were diagnosed idiopathic HP and 11 patients were secondary HP. Demographic data and imaging findings reveal the following: configuration, thickness, signal intensity on T1-weighted image (T1WI), T2-weighted image (T2WI), and enhancement pattern of the lesions. The data were analyzed by T-test and Fisher’s exact test.

Result

Secondary HP were significantly located at anterior and middle cranial fossa (P = 0.033). There is no significant difference of lesions in configurations, T1 and T2 signal intensity and patterns of enhancement. There was significant and exclusive difference in T2 hypointense/dark intensity and homogeneous enhancement in idiopathic HP (75%, P = 0.044).

Conclusions

MRI may play a complimentarily important role in distinguishing idiopathic HP from secondary HP. Idiopathic HP is probably preferred diagnosis in the lesions with T2-rim pattern and T2 hypointense/dark intensity with homogeneous enhancement.

Pachymeningitis Demonstrated on Gallium SPECT/CT Scan

A 34-year-old woman presented with a 3-month history of right-sided headaches associated with photophobia and pulsatile tinnitus. Investigations including lumbar puncture revealed elevated opening CSF pressure, increased protein, and presence of monocytosis consistent with an inflammatory/infective process. Brain MRI showed an area of thickened enhancing dura around the venous sinus posteriorly. Ga scintigraphy demonstrated focal intracranial uptake in the posterior occipital region, and biopsy confirmed a chronic inflammatory infiltrate with no granulomas.

Hypertrophic cervical spine pachymeningitis due to sarcoidosis: a case report

Hypertrophic pachymeningitis (HP) is a chronic, progressive diffuse inflammatory condition that leads to thickening of the dura mater and can be idiopathic or associated with sarcoidosis among other disorders. In this case report, we present a rare case of cervical spine HP in a 29-year-old woman in the post-partum period, who had a history of pituitary adenoma and juvenile rheumatoid arthritis. Magnetic resonance imaging (MRI) of the spine revealed a soft tissue mass and moderate cord compression. The patient underwent C3-C7 laminectomy. Pathological analysis of the cervical epidural mass demonstrated a reactive inflammatory cell process. Recurrence of symptoms and worsening of pachymeningitis on imaging studies warranted further work-up which revealed mediastinal/hilar lymphadenopathy. Transbronchial biopsy revealed non-caseating granulomatous disease consistent with sarcoidosis. The patient was started on oral steroids and eventually methotrexate with significant clinical and radiographic improvement. Follow-up imaging studies showed minimal dural thickening in the thoracic spine and eventually complete resolution. HP should be considered in a patient with spinal cord compression, myelopathy, and radicular pain of unclear etiology, and sarcoidosis should be considered in idiopathic cases.

Hypertrophic pachymeningitis associated with antineutrophil cytoplasmic antibody-associated vasculitis: a case series of 15 patients

OBJECTIVE

We aimed to describe the clinical characteristics and treatment course of hypertrophic pachymeningitis (HPM) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

METHODS

We retrospectively analysed 15 patients (11 men and four women). HPM was diagnosed based on thickening and enhancing of the brain and/or spinal dura mater on gadolinium-enhanced magnetic resonance imaging (MRI) T1 sequence.

RESULTS

The median age at HPM onset was 60 years. Headache and cranial nerve impairment were observed in 14 and 10 patients, respectively. Otitis media and/or mastoiditis were found as complications of AAV in 11 patients. Fourteen patients were classified as having granulomatosis with polyangiitis (GPA). Single-positive myeloperoxidase-ANCA, single-positive proteinase 3-ANCA, and double-positive ANCA were identified in seven patients, five patients, and one patient, respectively. With MRI, thickening of the dura mater in the cranial fossa and tentorium cerebelli was found in 10 and eight patients, respectively. For remission induction, all patients were treated with corticosteroids, and immunosuppressants were added in 10 patients. Dura mater thickening partially improved in all patients, and cranial neuropathy completely remitted in eight patients. In a median follow-up of 43 months, four patients had HPM relapse and underwent reinduction therapy. All six patients treated with cyclophosphamide at initial therapy did not relapse.

CONCLUSIONS

HPM was mostly associated with patients with GPA with otitis media and/or mastoiditis having either type of ANCA serology. Treatment with corticosteroids with or without immunosuppressants was effective. However, HPM relapse occasionally occurred, especially when cyclophosphamide was not used in initial treatment.

Rapidly progressive fatal idiopathic hypertrophic pachymeningitis with brainstem involvement in a child

BACKGROUND

Hypertrophic pachymeningitis (HP) is a rare disorder characterized by diffuse thickening of the dura mater with resultant neurologic deficits. HP develops secondary to various conditions or idiopathically usually in adults but rarely in children.

CASE REPORT

We describe a 3-year-old female child with idiopathic HP. Her HP involved the entire central nervous system with progression into the brainstem. The lesion responded poorly to pulsed steroids or any immunosuppressants. The brainstem lesion grew rapidly and formed various nodules that ultimately resulted in brain death. This is the first fatal case of HP in a child.

Diplopia With Dural Fibrotic Thickening

Idiopathic hypertrophic pachymeningitis (HP) is a rare disorder of diffuse thickening of the cranial or spinal dura mater without an identifiable cause. Most common in adult males, idiopathic HP typically presents with headache with or without varied associated focal neurologic deficits and findings of dural enhancement on magnetic resonance imaging in a linear, nodular, or combined pattern. As it is felt to be an autoimmune disorder, treatment with high-dose corticosteroids is typically recommended, and without intervention, the course is usually progressive. The disease can commonly progress with a relapsing remitting course requiring other immune modulators such as methotrexate, azathioprine, or cyclophosphamide for control. Here, we describe a unique case of idiopathic HP as it presented in a pediatric patient and resolved without immunomodulatory therapy.

Idiopathic hypertrophic pachymeningitis as a rare cause of cervical compressive myelopathy

The spinal form of idiopathic hypertrophic pachymeningitis (IHP) is a rare condition characterized by a chronic progressive diffuse inflammatory fibrosis of the dura mater, which may evolve to the compression of the spinal cord. We present a case report about IHP focusing on its features in magnetic resonance imaging, which are determined by an intradural extramedullary mass in the cervical spine showing hypointensity on T2-weighted images and peripheral enhancement, causing compression of the spinal cord. Histological analysis showed a nonspecific chronic inflammatory process in dense fibrous tissue. The patient had a good outcome after therapy with steroids.

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.

Rituximab Treatment for Idiopathic Hypertrophic Pachymeningitis

BACKGROUND AND PURPOSE

Hypertrophic pachymeningitis (HP) is a rare disease caused by autoimmunity in the meninx that causes various neurologic symptoms, including headache, seizures, weakness, paresthesia, and cranial nerve palsies. Although the first-line therapy for HP is steroids, many HP cases are refractory to steroids or recur when the steroids are tapered. Here we report three HP cases that were successfully treated with rituximab (RTX).

METHODS

From an institutional cohort recruited from April 2012 to July 2016, three HP cases that were identified to be steroid-refractory were treated with RTX (four weekly doses of 375 mg/m²). Clinical improvement was assessed by the number of relapses of any neurologic symptom and the largest dural thickness in MRI.

RESULTS

All three patients were recurrence-free of neurologic symptoms and exhibited prominent decreases in the dural thickness after RTX treatment. No adverse events were observed in the patients.

CONCLUSIONS

We suggest RTX as a second-line therapy for steroid-refractory HP. Further studies are warranted to confirm this observation in a larger population and to consider RTX as a first-line therapy.

Effective Response of Methotrexate for Recurrent Idiopathic Hypertrophic Spinal Pachymeningitis

Idiopathic hypertrophic spinal pachymeningitis (IHSP) is a chronic progressive and diffuse inflammatory fibrosis of the spinal dura mater. Though treatment of IHSP is surgical decompression with steroid therapy, treatment for recurrent IHSP is controversial. Our patient was diagnosed with IHSP based on magnetic resonance imaging (MRI) and underwent laminectomy for decompression following steroid pulse therapy. Despite maintenance of steroid therapy, the patient experienced 3 recurrences. As an alternative immunosuppressant medication, methotrexate was introduced with low-dose steroid. Fortunately, the symptom was resolved, and a decrease of dura thickening was revealed on MRI. We present the case and suggest that methotrexate might be an effective treatment modality for recurrent IHSP.

Hypertrophic Pachymeningitis as an Early Manifestation of Relapsing Polychondritis: Case Report and Review of the Literature

Neurological involvement in relapsing polychondritis (RP) is relatively rare. We describe the case of an 80-year-old man who presented with hypertrophic pachymeningitis (HP) together with arthritis as the first manifestation of RP. Auricular chondritis, which subsequently determined the diagnosis of RP, occurred a few weeks after the detection of HP. The neurological symptoms, as well as arthritis, were promptly improved by treatment with corticosteroids. It is generally difficult to diagnose RP in the absence of typical cartilaginous involvement; however, the present case suggests that HP may occur as an early clinical manifestation of RP.

‘Eiffel-by-Night’: A New MR Sign Demonstrating Reactivation in Idiopathic Hypertrophic Pachymeningitis

A forty- seven-year-old man presented with chronic headache with lower cranial nerve palsies of ten year duration with recent aggravation of symptoms. MRI revealed hypointensity — predominantly of the posterior falx cerebri and the tentorium cerebelli — on all sequences with intense peripheral contrast enhancement on CE SE T1, which on coronal images mimicked the illuminated Eiffel tower by night.

Hypertrophic pachymeningitis with sarcoidosis: a rare cause of craniocervical compression

We describe a case of a 58-year-old woman with a suspected dural tumour. She presented with progressive pyramidal weakness. MRI confirmed compression of the medulla oblongata and spinal cord at the level of C1-3. The localised dural mass lesion homogenously enhanced on T1 MRI and was considered most likely to be a meningioma. Incidentally, CT scan of the chest revealed peribronchial soft tissue thickening, suggestive of pulmonary sarcoidosis. Owing to the progressive nature of her weakness, she had a posterior occipitocervical decompression with a C1-3 laminectomy and resection of the thickened dura. Histology showed densely collagenous tissue with scanty psammoma bodies and multinucleate giant cells, consistent with hypertrophic pachymeningitis (HP)-a rare, chronic inflammatory condition, characterised by thickening and fibrosis of the dura. This case demonstrates that masses in the craniocervical junction can be varied in pathology and when there is evidence of systemic inflammation, HP should be considered.

Immunoglobulin-G4-related hypertrophic pachymeningitis with antineutrophil cytoplasmatic antibodies effectively treated with rituximab

We describe a 52-year-old man with hypertrophic pachymeningitis (HP) who was both seropositive for antineutrophil cytoplasmatic antibodies (ANCA) against myeloperoxidase, and had an immunoglobulin G4 (IgG4) positive fibroinflammatory response in meningeal biopsy. HP is a chronic inflammatory thickening of the dura mater which typically presents with headache, cranial nerve dysfunction and other neurological deficits. While first-line treatment with corticosteroids is recommended, many patients relapse and need additional immunosuppression. One recently described etiology is IgG4-related disease and in a subgroup of idiopathic patients, evidence suggests a crucial role of ANCA. To our knowledge, the simultaneous occurrence of IgG4-related disease and ANCA has not been reported so far. This man suffered life-threatening disease progression despite the administration of high dose steroids, cyclophosphamide and azathioprine. Treatment with rituximab was initiated which led to disappearance of clinical symptoms and decrease of dural thickening within weeks. This patient presents a possible disease overlap of IgG4-related and ANCA-associated HP and illustrates the effectiveness of rituximab in refractory IgG4-related HP.

Clinico-radiological spectrum and outcome in idiopathic hypertrophic pachymeningitis

OBJECTIVE

To elucidate the clinico-radiological features, treatment response and outcome of a large cohort of patients (n=20) with idiopathic hypertrophic pachymeningitis (IHP) and to examine if any of these features could differentiate between IHP and secondary causes of hypertrophic pachymeningitis (SHP).

METHODS

20 patients with IHP diagnosed between 1998 and 2009 formed the study cohort. We adopted a validated clinical score to quantitatively assess and document their neurological disability and to compare their pre- and post-treatment outcomes. Appropriate statistical analysis was done to look for any clinical and/or radiological features to differentiate IHP from SHP.

RESULTS

Out of the twenty eight consecutive patients with pachymeningitis, 20 were having IHP and 8 were having SHP (Tuberculosis-5, Sarcoidosis-2, Wegener's granulomatosis-1). In IHP, headache and visual symptoms dominated the clinical symptomatology (80% and 75%). In MRI, the peripheral pattern of contrast enhancement was more common with IHP (p=0.03). The posterior falx and tentorium showing a hypointense center ("fibrosis") and enhancing periphery ("active inflammation") together mimicking "Eiffel-by-night" sign was found to be more commonly associated with IHP (60% vs 12.5%, p=0.03). Biopsy was done in 9 patients. At a mean follow-up of 51 months (range 24-144 months), the mean pretreatment clinical score improved from 6.55 to 1.80 in 20 patients with IHP (p<0.001).

CONCLUSIONS

Our data on the largest cohort of patients with IHP would shed light into its clinico-radiological spectrum, treatment and outcome. The prognosis is satisfactory if managed appropriately. We have highlighted the role of MRI in differentiating between IHP and other causes of SHP.

[Optic neuropathy in a case of recurrent idiopathic hypertrophic pachymeningitis unresponsive to steroids and immunosuppressants]

CASE REPORT

A 38-year-old female patient with bilateral papilledema who presented with loss of vision in her left eye. The Magnetic Resonance Imagining (MRI) showed thickening of the dura mater, and the intracranial pressure was elevated. A cancer, infectious, and autoimmune origin was ruled out.

DISCUSSION

The initial response to high doses of corticoids was satisfactory, with disappearance of the optic disc enema, with visual acuity and an improvement in the MRI. However, after one year without treatment she had a new outbreak of the disease. Despite renewed treatment with corticoids and azathioprine, the patient developed a left optic neuropathy and irreversible visual loss.

Idiopathic hypertrophic spinal pachymeningitis with an osteolytic lesion

Idiopathic hypertrophic spinal pachymeningitis (IHSP) is a chronic, progressive, inflammatory disorder characterized by marked fibrosis of the spinal dura mater with unknown etiology. According to the location of the lesion, it might induce neurologic deficits by compression of spinal cord and nerve root. A 58-year old female with a 3-year history of progressive weakness in both lower extremities was referred to our institute. Spinal computed tomography (CT) scan showed an osteolytic lesion involving base of the C6 spinous process with adjacent epidural mass. Magnetic resonance imaging (MRI) revealed an epidural mass involving dorsal aspect of cervical spinal canal from C5 to C7 level, with low signal intensity on T1 and T2 weighted images and non-enhancement on T1 weighted-enhanced images. We decided to undertake surgical exploration. At the operation field, there was yellow colored, thickened fibrous tissue over the dura mater. The lesion was removed totally, and decompression of spinal cord was achieved. Symptoms improved partially after the operation. Histopathologically, fibrotic pachymeninges with scanty inflammatory cells was revealed, which was compatible with diagnosis of idiopathic hypertrophic pachymeningitis. Six months after operation, motor power grade of both lower extremities was normal on physical examination. However, the patient still complained of mild weakness in the right lower extremity. Although the nature of IHSP is generally indolent, decompressive surgery should be considered for the patient with definite or progressive neurologic symptoms in order to prevent further deterioration. In addition, IHSP can present as an osteolytic lesion. Differential diagnosis with neoplastic disease, including giant cell tumor, is important.

Arachnoid involved in idiopathic hypertrophic pachymeningitis

The cerebrospinal fluid (CSF) shows inflammatory changes in patients with idiopathic hypertrophic pachymeningitis (IHP), which is a rare disorder. However, systemic CSF research including immunoglobulins in patients with IHP are substantially lacking. In the study, clinical, laboratory, neuroradiologic and therapeutic data from 9 patients with IHP were retrospectively studied, and CSF changes were analyzed. Intracranial pressure was elevated in 4 patients. Protein levels in CSF were elevated in 5 patients (< 1g/L). IgA was elevated in 7 patients (> 0.5mg/dL), IgG was elevated in 8 patients (> 3.4 mg/dL) and IgM was elevated in 6 patients (>0.13 mg/dL) with IHP. CSF immunoglobulins, including IgA, IgG and IgM, were significantly elevated compared with levels in the control (P = 0.021, 0.018, 0.019). There were no linear correlations between IgG, IgM and protein in CSF, but there was a linear correlation between IgA and protein. In conclusion, CSF in IHP shows inflammatory changes, and protein levels are low to moderately elevated. CSF immunoglobulins, including IgA, IgG and IgM, also increased. The arachnoid is involved in IHP, a proportion of immunoglobulins may originate from the blood because of damage to the blood-CSF barrier at the arachnoid. Other intrathecal synthesis of immunoglobulins may be a secondary change due to alteration in the CSF's content to stabilize the internal environment or may be secreted by activated immune memory cells in the brain, which need further research.

IgG4-related intracranial hypertrophic pachymeningitis with skull hyperostosis: a case report

BACKGROUND

Immunoglobulin G4 (IgG4)-related disease is a systemic syndrome, characterized by sclerosing lesions and usually associated with a raised serum IgG4 level; the pancreas, salivary glands, and lacrimal glands are typically affected. Recently, it has been suggested that IgG4-related sclerosing disease represents a subset of cases previously diagnosed as idiopathic hypertrophic pachymeningitis. This rare inflammatory disorder causes localized or diffused thickening of intracranial dura mater. Headache, cranial nerve palsy, and ataxia are the most common clinical manifestations.Herein, we report the clinical and histopathological features of a rare case of IgG4-related intracranial hypertrophic pachymeningitis involving cranial hyperostosis.

CASE PRESENTATION

A 52-year-old man presented with refractory generalized tonic-clonic seizure. Magnetic resonance imaging revealed thickening of the meninges with enhancement near the superior sagittal sinus; skull bone defect was also noted. Extensive excision of affected skull bone and dura was performed, providing the diagnosis of IgG4-related pachymeningitis. After the surgery, the patient's seizure stopped and he was smoothly tapered off antiepileptic medication.

CONCLUSION

To our knowledge, this is the first reported case of IgG4-related pachymeningitis with concomitant skull hyperostosis.

IgG4-related disease: nomenclature, clinical features, and treatment

Concepts about IgG4-related disease (IgG4-RD) are now emerging swiftly. The condition has been identified in virtually every organ system, and its features are often excellent mimickers of malignancies, infections, and other immune-mediated disorders. Recommendations for nomenclature were proposed by the Organizing Committee of the 2011 International IgG4-related disease Symposium, and guidelines for the pathologic diagnosis of this condition have been published by an international group of experts. Experience with treatment regimens is growing. Glucocorticoids and B-cell depletion strategies both appear to be effective and are the subject of ongoing studies. This article reviews the current thought and understanding of this disease with regard to nomenclature, organ system involvement, and approaches to therapy.

Hypertrophic cranial pachymeningitis and skull base osteomyelitis by pseudomonas aeruginosa: case report and review of the literature

Hypertrophic cranial pachymeningitis (HCP) is an uncommon disorder characterized by localized or diffuse thickening of the dura mater, and it usually presents with multiple cranial neurophaties. It has been associated with a variety of inflammatory, infectious, traumatic, toxic and neoplasic diseases, when no specific cause is found the process is called idiopathic. The infectious cases occur in patients under systemic immunosuppression, which have an evident contiguous source or those who have undergone neurosurgical procedures. We describe a case of a 62-year-old immunosuppressed woman with diabetes and rheumatoid arthritis, which had HCP and osteomyelitis of the skull base caused by pseudomonas aeruginosa, presenting with headache and diplopia. We believe this is the second documented case of pachymeningitis secondary to this microorganism. As a multifactorial disease, it is essencial to determine the specific causative agent of HCP before making treatment decisions, and great care is needed with immunocompromised patients.

The Clinical and Pathological Features of IgG(4)-Related Disease

The rapidly emerging disorder now known as IgG(4)-related disease (IgG(4)-RD) includes a variety of clinical entities once regarded as being entirely separate diseases. Manifestations of IgG(4)-RD have now been reported in essentially all organ systems. Regardless of which organ is involved, tissue biopsies reveal striking histopathological similarities. The hallmark pathology findings are diffuse lymphoplasmacytic infiltrates, abundant IgG(4)-positive plasma cells, modest tissue eosinophilia, and extensive fibrosis. Tumorous swelling and obliterative phlebitis are other frequently observed features. Polyclonal elevations of serum IgG(4) are found in approximately 70% of patients. Many questions pertaining to the etiology, pathophysiology, epidemiology, clinical features, therapy, disease monitoring, and long-term outcomes remain to be addressed. This paper focuses on the clinical and pathological features of IgG(4)-RD.

IgG4-related sclerosing disease, an emerging entity: a review of a multi-system disease

Immunoglobulin G4-related systemic disease (IgG4-RSD) is a recently defined emerging entity characterized by a diffuse or mass forming inflammatory reaction rich in IgG4-positive plasma cells associated with fibrosclerosis and obliterative phlebitis. IgG4-RSD usually affects middle aged and elderly patients, with a male predominance. It is associated with an elevated serum titer of IgG4, which acts as a marker for this recently characterized entity. The prototype is IgG4-related sclerosing pancreatitis or autoimmune pancreatitis (AIP). Other common sites of involvement are the hepatobiliary tract, salivary gland, orbit, and lymph node, however practically any organ can be involved, including upper aerodigestive tract, lung, aorta, mediastinum, retroperitoneum, soft tissue, skin, central nervous system, breast, kidney, and prostate. Fever or constitutional symptoms usually do not comprise part of the clinical picture. Laboratory findings detected include raised serum globulin, IgG and IgG4. An association with autoantibody detection (such as antinuclear antibodies and rheumatoid factor) is seen in some cases. Steroid therapy comprises the mainstay of treatment. Disease progression with involvement of multiple organ-sites may be encountered in a subset of cases and may follow a relapsing-remitting course. The principal histopathologic findings in several extranodal sites include lymphoplasmacytic infiltration, lymphoid follicle formation, sclerosis and obliterative phlebitis, along with atrophy and destruction of tissues. Immunohistochemical staining shows increased IgG4+ cells in the involved tissues (>50 per high-power field, with IgG4/IgG ratio >40%). IgG4-RSD may potentially be rarely associated with the development of lymphoma and carcinoma. However, the nature and pathogenesis of IgG4-RSD are yet to be fully elucidated and provide immense scope for further studies.

Idiopathic hypertrophic cranial pachymeningitis: Three biopsy-proven cases including one case with abdominal pseudotumor and review of the literature

Hypertrophic pachymeningitis (HP) is a rare disorder of diverse etiology. It presents with headaches, cranial neuropathies and ataxia occurring alone or in combination. Dural biopsy is essential to exclude secondary causes of pachymeningitis. There is paucity of data on biopsied cases of HP. We report three biopsy-proven cases of idiopathic hypertrophic cranial pachymeningitis. All our patients had headaches and multiple cranial neuropathies; ataxia was seen in one patient. One patient had recurrent anterior and posterior cranial neuropathies, while one each had recurrent anterior and posterior cranial neuropathies. Two patients had profound irreversible mono-ocular visual loss. All of them showed prominent pachymeningeal thickening on imaging. Infarcts were seen in one patient, which have rarely been documented. All patients showed biopsy evidence of meningeal thickening and nonspecific chronic inflammation of the dura. The disease may have a remitting and relapsing course, and usually responds to steroids. Clinical improvement was excellent in two patients and modest in one on steroid therapy. All our patients required azathioprine during the course of therapy. Early institution and long-term maintenance of steroid therapy prevents neurologic sequelae. Occurrence of abdominal inflammatory pseudotumor in a patient of HP possibly as part of multifocal fibrosclerosis has not been described earlier.

Long-term outcome of idiopathic hypertrophic thoracic pachymeningitis

Idiopathic hypertrophic spinal pachymeningitis (IHSP) is a comparatively rare disease characterized by hypertrophic inflammation of the dura mater and clinical symptoms that progress from local pain to myelopathy. We report a case of IHSP followed up for 20 years in a 46-year-old man. Expansive laminoplasty was performed in 1991, and this case has been previously reported by a co-author. After 17 years, the patient's gait disturbance returned. Physical examination and imaging confirmed IHSP that had developed into syringomyelia at the T2-L1 conus level. This case was diagnosed as adhesive spinal arachnoiditis due to pachymeningitis caused by syringomyelia. T1-T4 laminectomy, a syringo-subarachnoid shunt (S-S shunt), and L2-L3 laminectomy were performed. The patient again developed dysesthesia and gait disturbance 3 years after the second operation. Most reports of IHSP have limited their focus to short-term follow-up after initial treatment with no long-term results. At present, there are only five reports referring to long-term results of greater than 5 years. All but one case needed additional surgery. To the best of our knowledge, this is the first case in which syringomyelia occurred in a patient with IHSP. It is important to note that syringomyelia may be a cause of symptom recrudescence during long-term follow-up in IHSP patients.

Idiopathic hypertrophic spinal pachymeningitis

Spinal idiopathic hypertrophic pachymeningitis (IHP) is a rare, chronic, nonspecific, granulomatous inflammatory disorder of the dura with unknown etiology. It can cause a localized or diffuse thickening of the dura mater with compression of the spinal canal and possible myelopathic symptoms. The authors report 3 consecutive cases of spinal IHP with a review of the literature. The diagnosis of spinal IHP was based on biopsy and pathological confirmation. Typical MR imaging findings suggestive of spinal IHP were noted in all cases. The clinical course may be marked by deterioration despite conservative therapy and may require surgical intervention to prevent irreversible neurological damage. Therefore, prompt diagnosis and institution of proper treatment is critical.

A clinical overview of IgG4-related systemic disease

PURPOSE OF REVIEW

To summarize the existing knowledge of various clinical presentations of IgG4-related systemic disease (IgG4-RSD) and to review the evolving list of organs affected by IgG4-RSD.

RECENT FINDINGS

The term IgG4-RSD encompasses a variety of clinical entities once regarded as being entirely separate diseases. The list of organs associated with this condition is growing steadily. Tissue biopsies reveal striking histopathological similarity, regardless of which organ is involved, although subtle differences across organs exist. Diffuse lymphoplasmacytic infiltrates, presence of abundant IgG4-positive plasma cells and extensive fibrosis are the hallmark pathology findings. Tumorous swelling, eosinophilia, and obliterative phlebitis are other frequently observed features. Polyclonal elevations of serum IgG4 are found in most but not all patients.

SUMMARY

IgG4-RSD is an underrecognized condition about which knowledge is now growing rapidly. Yet there remain many unknowns with regard to its cause, pathogenesis, various clinical presentations, approach to treatment, disease monitoring, and long-term outcomes. A wide variety of organs can be involved in IgG4-RSD. Clinicians should be aware of this entity and consider the diagnosis in the appropriate settings.

Idiopathic Hypertrophic Cranial Pachymeningitis Associated With Intermediate Uveitis

The authors report a case with idiopathic hypertrophic cranial pachymeningitis associated with intermediate uveitis. The patient complained of decreased vision in both eyes, especially the right. Ophthalmic examination revealed right optic disc pallor, bilateral vitritis, and cystoid macular edema. Magnetic resonance imaging revealed marked enhancement of a dural lesion. The macular edema responded well to medical treatment. Intermediate uveitis has not yet been reported in the context of idiopathic hypertrophic cranial pachymeningitis.

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

IgG4-related disease has evolved from originally being recognized as a form of pancreatitis to encompass diseases of numerous organs including the hypophysis and one reported case of dural involvement. A search of the University of Virginia, Division of Neuropathology files for 10 years identified ten cases of unexplained lymphoplasmacytic meningeal inflammation that we then evaluated using immunohistochemical stains for IgG4 and IgG. Ten control cases including sarcoidosis (4), tuberculosis (1), bacterial abscess (2), Langerhans cell histiocytosis (2), and foreign body reaction (1) were also examined. The number of IgG4-positive plasma cells was counted in five high power fields (HPFs) and an average per HPF was calculated. Cases that contained greater than ten IgG4-positive cells/HPF were considered to be IgG4-related. Five of the study cases met these criteria, including one case of leptomeningeal inflammation. All cases exhibited the typical histological features of IgG4-related disease including lymphoplasmacytic inflammation, fibrosis, and phlebitis. The dural-based lesions appear to represent a subset of the cases historically diagnosed as idiopathic hypertrophic pachymeningitis. While the leptomeningeal process most closely resembles non-vasculitic autoimmune inflammatory meningoencephalitis. Given these findings, IgG4-related meningitis should be considered in the differential diagnosis of meningeal inflammatory lesions after stringent clinical and histologic criteria are used to rule out other possible diagnoses.

IgG4-related sclerosing disease: a critical appraisal of an evolving clinicopathologic entity

An elevated serum titer of immunoglobulin G4 (IgG4), the least common (3% to 6%) of the 4 subclasses of IgG, is a surrogate marker for the recently characterized IgG4-related sclerosing disease. The syndrome affects predominantly middle-aged and elderly patients, with male predominance. The patients present with symptoms referable to the involvement of 1 or more sites, usually in the form of mass lesions. The prototype is IgG4-related sclerosing pancreatitis (also known as autoimmune pancreatitis), most commonly presenting as painless obstructive jaundice with or without a pancreatic mass. Other common sites of involvement are the hepatobiliary tract, salivary gland, orbit, and lymph node, but practically any organ-site can be affected, such as retroperitoneum, aorta, mediastinum, soft tissue, skin, central nervous system, breast, kidney, prostate, upper aerodigestive tract, and lung. The patients usually have a good general condition, with no fever or constitutional symptoms. Common laboratory findings include raised serum globulin, IgG, IgG4, and IgE, whereas lactate dehydrogenase is usually not raised. Some patients have low titers of autoantibodies (such as antinuclear antibodies and rheumatoid factor). The disease often shows excellent response to steroid therapy. The natural history is characterized by the development of multiple sites of involvement with time, sometimes after many years. However, the disease can remain localized to 1 site in occasional patients. The main pathologic findings in various extranodal sites include lymphoplasmacytic infiltration, lymphoid follicle formation, sclerosis and obliterative phlebitis, accompanied by atrophy and loss of the specialized structures of the involved tissue (such as secretory acini in pancreas, salivary gland, or lacrimal gland). The relative predominance of the lymphoplasmacytic and sclerotic components results in 3 histologic patterns: pseudolymphomatous, mixed, and sclerosing. Immunostaining shows increased IgG4+ cells in the involved tissues (>50 per high-power field, with IgG4/IgG ratio >40%). The lymph nodes show multicentric Castleman disease-like features, reactive follicular hyperplasia, interfollicular expansion, or progressive transformation of germinal centers, with the unifying feature being an increase in IgG4+ plasma cells on immunostaining. The nature and pathogenesis of IgG4-related sclerosing disease are still elusive. Occasionally, the disease can be complicated by the development of malignant lymphoma and possibly carcinoma.

Idiopathic hypertrophic cranial pachymeningitis misdiagnosed as acute subtentorial hematoma

A case of idiopathic hypertrophic cranial pachymeningitis (IHCP) misdiagnosed as an acute subdural hematoma is reported. A 37-year-old male patient presented with headache following head trauma 2 weeks earlier. Computerized tomography showed a diffuse high-density lesion along the left tentorium and falx cerebri. Initial chest X-rays revealed a small mass in the right upper lobe with right lower pleural thickening, which suggested lung cancer, such as an adenoma or mediastinal metastasis. During conservative treatment under the diagnosis of a subdural hematoma, left cranial nerve palsies were developed (3rd and 6th), followed by scleritis and uveitis involving both eyes. Magnetic resonance imaging (MRI) revealed an unusual tentorium-falx enhancement on gadolinium-enhanced T1-weighted images. Non-specific chronic inflammation of the pachymeninges was noticed on histopathologic examination following an open biopsy. Systemic steroid treatment was initiated, resulting in dramatic improvement of symptoms. A follow-up brain MRI showed total resolution of the lesion 2 months after steroid treatment. IHCP should be included in the differential diagnosis of subtentorial-enhancing lesions.