MPO-ANCA-Positive Hypertrophic Pachymeningitis With Elevated Serum IgG4: A Case Report and Literature Review.

Abstract Background: We report a case of serum myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA)-positive hypertrophic pachymeningitis with elevated serum immunoglobulin G (IgG)4. Case presentation: He was a 67-year-old man who appeared headache and hearing loss 7 years ago. He was treated with methylprednisolone and mycophenolate when he was diagnosed with hypertrophic pachymeningitis 2 years ago. He went to the hospital this time because of fatigue and appetite, the results of his blood tests indicated a progressive increase in creatinine and an increase in MPO and IgG4. His kidney biopsy revealed very few infiltrating IgG4-positive cells. Instead, fibrinoid necrosis of arterioles was observed. Considering the clinical process and these findings, the disease was considered more likely to be ANCA-associated hypertrophic pachymeningitis with elevated serum IgG4 level. Conclusions: Our case highlights the importance of the pathological examination and the medical history. Pathological examination and previous medical history play an essential role in the diagnosis of the disease. Only when the disease is correctly diagnosed can it be further treated effectively and get a better prognosis. Data Sources: Data were collected from the patient’s electronic medical records and the hospital laboratory medicine database.