Multi-institutional Retrospective Analysis of Hypertrophic Pachymeningitis  
Jiyeon Son1, Rohini Samudralwar2, Joseph Berger2, Giovanna Manzano3, Stacey Clardy4, Ilya Kister1, Spencer Hutto5, Kiran Thakur6, Sarah Wesley6, Andrew Morrison2, Sage Hewitt7, Wesley Peng3, Hannah Kelly3, Trevor Glenn3, Alexandra Balshi3, Yoji Hoshina4, Amanda Zhao1, Gerome Vallejos6, Wen-Yu Lee1, Yidan Shi1, Siddharama Pawate7
1NYU Grossman School of Medicine, 2Perelman School of Medicine at the University of Pennsylvania, 3Massachusetts General Hospital, 4University of Utah School of Medicine, 5Emory School of Medicine, 6Columbia University College of Physicians and Surgeons, 7Vanderbilt University Medical Center
Objective:
To characterize clinical, paraclinical, pathological features of hypertrophic pachymeningitis (HP).
Background:
HP is a rare clinico-radiologic inflammatory syndrome associated with thickening/enhancement of dura mater. HP can be due to various inflammatory, infectious, and neoplastic processes. Dural biopsy remains the gold standard for diagnosis but is frequently non-diagnostic.
Design/Methods:
Patients with HP were identified through comprehensive electrical medical records query. We required that all patients have dural thickening and/or enhancement on MRI. Investigators--neurologists at 7 academic medical centers – abstracted demographic, clinical, radiographic, and histopathologic data. Descriptive statistics are presented.
Results:
Of the 113 patients with HP, 55% were female, most were White (n=78, 69.0%), followed by Black/African American (n=14, 12.4%), and Others (n=8, 7.1%). The most common presenting symptoms were headaches (n=69, 59.3%), visual loss (n=20, 17.7%), other (n=21, 18.6%), and cognitive impairment (n=18, 15.9%). MRI pattern showed diffuse dural enhancement in 69 (61.1%) and focal in 41 (36.3%); smooth enhancement was seen in 82 (72.6%) and nodular in 27 (23.9%); 28 (24.8%) demonstrated leptomeningeal enhancement, and 23 (20.4%) were markedly thickened (>5mm). The most frequent additional sites of involvement were the cranial nerves (n=13, 11.5%), spinal cord (n=13, 11.5%), and orbits (12, 10.6%). 60 (53.1%) underwent dural biopsy. Idiopathic pachymeningitis was the most common working diagnosis (n=68, 60.2%), followed by sarcoidosis (n=16,14.2%), ANCA-associated vasculitis (n=8, 7.1%), rheumatoid arthritis (n=4, 3.5%), other (n=4, 3.5%), IgG4-related disease (n=3, 2.6%), infection (n=3, 2.6%), malignancy (n=3, 2.6%), Sjogren’s syndrome (n=2, 1.7%) and histiocytosis (n=2, 1.7%). 88 patients (80%) received any treatment, with 77 (87.5%) demonstrating clinical and/or radiographic improvement. The most common treatments were IVMP (n=70, 69.3%), IVMP with prednisone taper (n=42, 41.2%), and rituximab (n=26, 25.5%).
Conclusions:
We present a large, multi-institutional dataset on HP with diverse etiologies. Further analysis of etiology-specific characteristics and outcomes will inform future diagnostic and treatment strategies.
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