石灰化慢性硬膜下血腫に合併したextraaxial primary malignant lymphomaの1例

Extraaxial Primary Malignant Lymphoma Associated with Calcified Chronic Subdural Hematoma : a case report

I．はじめに

　中枢神経系原発性悪性リンパ腫は，移植医療に伴う免疫抑制剤の使用や後天性免疫不全症候群の増加など医療背景の変化も影響してその症例数の増加が指摘されている．しかしその報告例のほとんどが脳実質内腫瘍であり^2,6,16），脳実質外に発生するものはきわめて稀である．今回われわれは，石灰化慢性硬膜下血腫の外膜あるいはその直上の硬膜より発生したと思われる原発性悪性リンパ腫を経験したので，文献的考察を加え報告する．

The authors report the case of a 54-year-old male with extraaxial primary malignant lymphoma associ-ated with calcified chronic subdural hematoma. He slowly developed progressive headache accompaniedby a bulge in the left forehead. Skull radiogram showed a large biconvex calcification in the left frontopar-ietal region, with concave change in the overlying bone. Computed tomograms and magnetic resonance im-ages revealed a left frontoparietal chronic subdural hematoma surrounded by a calcified rim, with marginalenhancement in the frontal portion extending upward to the subcutaneous tissue through the underlyingbone. The lesion was suspected to be an infectious calcified hematoma. The patient underwent a cra-niotomy for the removal of the hematoma. It was observed that the tumor was located mainly in the epidu-ral and subdural space. The extent of the tumor corresponded with the enhanced area of the lesion in thepreoperative neuroimages. The histological diagnosis was malignant lymphoma of B cell origin. Generalexamination, which included hone marrow study and Ga scintigraphy, failed to prove systemic lymphoma.Extraaxial primary malignant lymphoma is extremely rare, and this is the first report of a lymphomaassociated with calcified chronic subdural hematoma. The authors review the literature and discuss the cli-nical features and the pathogenesis of the lesion.