<h3>Objective:</h3> We present a case-series of patients with intracranial pachymeningitis and outline their management for successful outcomes. <h3>Background:</h3> Hypertrophic pachymeningitis is characterized by focal/diffuse thickening of intracranial and/or intraspinal dura. <h3>Design/Methods:</h3> <h3>Case-1:</h3> 48-year-old-woman with Crohn’s disease, relapsing polychondritis, presented with persistent left-sided headaches. MRI brain revealed left-sided contrast-enhancing pachymeningeal thickening; CSF showed lymphocytic pleocytosis. Glucocorticoids, adalimumab, and methotrexate resulted in clinical and neuroimaging improvement. <h3>Case-2:</h3> 78-year-old-woman presented with intractable headache, bilateral sensorineural-hearing-loss and vision-impairment. MRI brain showed nodular, multifocal dural-thickening at clivus, parasellar region, cavernous-sinuses extension encasing major vessels at skull-base. CSF showed lymphocytic pleocytosis, protein and serology demonstrated IgG4-subclasses, attributing etiology to IgG4-related-disease. Steroids, methotrexate, and later IV-rituximab resulted in equivocal response. Intrathecal rituximab, resulted in clinical and imaging stabilization, from better CNS penetration. <h3>Case-3:</h3> 60-year-old woman, with sarcoidosis presented with severe headaches. MRI demonstrated contrast-enhancing dural thickening in left posterior-temporo-occipital regions. Brain-biopsy showed non-necrotizing granulomas involving dura, parenchyma consistent with sarcoidosis. Steroids and infliximab, lead to clinical and radiological improvement. <h3>Case-4:</h3> 76-year-old man with prior metastatic melanoma, post-chemotherapy (nivolumab+ipilimumab), presented with headaches. MRI showed diffuse intracranial contrast-enhancing pachymeningeal thickening. Chest CT-scan showed circumferential thickening, contrast-enhancing thoracic aorta indicating systemic vasculitis. Serologically, ANA 1:320, +SSA/SSB, ESR/CRP both >100 and ANCA was negative. Meningeal biopsy demonstrated granulomatosis with polyangiitis; etiology considered paraneoplastic. Steroids and methotrexate demonstrated clinical and radiological response. <h3>Case-5:</h3> 56-year-old woman presented with headaches and CN-VII palsy. MRI brain revealed hypertrophic pachymeningitis causing mass-effect on right lateral ventricle. ANCA serological positivity and biopsy demonstrated AFB-stain-negative caseating granulomas, consistent with ANCA-vasculitis. Rituximab led to complete resolution of both pachymeningeal and CN-VII enhancement. <h3>Results:</h3> Clinical resolution and radiological stability was achieved for all 5 patients. <h3>Conclusions:</h3> Intracranial pachymeningitis presents in setting of systemic autoimmune disorders and sarcoidosis. Brain imaging, CSF-analysis, serological immune-markers, and biopsy aid in diagnosis. Immunosuppressive therapies provide for clinical and radiologic stabilization. <b>Disclosure:</b> Dr. Varma-Doyle has nothing to disclose. Dr. Manzano has nothing to disclose. Dr. Venna has nothing to disclose.