IgG4関連肥厚性硬膜炎の1例

A Case of IgG4-related Hypertrophic Pachymeningitis

Ⅰ．はじめに

　肥厚性硬膜炎は，脳脊髄硬膜に線維性肥厚を来す慢性炎症性疾患である．近年，その原因の1つとして，IgG4関連の炎症性機序が明らかになってきている^1,5,11)．今回われわれは，びまん性の髄膜肥厚を認める症例に対して硬膜生検を施行し，IgG4関連の肥厚性硬膜炎と診断した症例を経験したため，症例を提示して文献的考察を加える．

　Hypertrophic pachymeningitis is a chronic inflammatory disease, manifesting as a fibrous thickening of the dura mater. Recently, it was reported that IgG4 is related to the etiology of some diseases, such as pancreatitis. Here, we report a case of hypertrophic pachymeningitis related to infiltration of IgG4 positive plasma cells. A 68-year-old man presented at a nearby hospital with a headache and a low-grade fever. A blood test revealed inflammation, as well as elevation of IgG4 level. Magnetic resonance imaging（MRI）revealed diffuse thickening of the dura mater, dominantly in the posterior fossa and cerebellar tentorium. The lesion was enhanced significantly with gadolinium（Gd）. An open biopsy was performed to determine pathological diagnosis. Hematoxylin and eosin staining showed infiltration of inflammatory cells, including plasma cells. The infiltrating cells were positive for the IgG4. Post-operatively, the patient was treated with glucocorticoid, and both the inflammation and patient symptoms were improved. In conclusion, IgG4 is related to the etiology of hypertrophic pachymeningitis and glucocorticoid therapy is effective for this disease.