頭蓋底原発悪性リンパ腫の1例

A Case of Malignant Lymphoma in the Skull Base

I．はじめに

　最近，脳原発の悪性リンパ腫が増加しているが^7,8），われわれは，海綿静脈洞症候群にて発症した頭蓋底部原発と思われる悪性リンパ腫を経験した．咽頭・副鼻腔からの浸潤例を除くと同部原発の悪性リンパ腫は極めて稀であり^9,13），症例を呈示するとともに，このような症例を含む脳神経外科領域の悪性リンパ腫の治療方針について言及したい．

A case of malignant lymphoma located in the clivus, sella and cavernous sinus is reported. A 46-year-old female was hospitalized with a 3-week history of diplo-pia. Neurological examination showed left oculomotor, trochlear, abducens and hypoglossal nerve palsy. Im-provement of cranial nerve palsy was achieved with the administration of prednisolone but it was only transient. Laboratory studies and endocrinological examination showed almost no abnormal findings. Skull x-ray film re-vealed a widely damaged base. MR studies showed a homogenously enhanced mass lesion in the clivus, sella and bilateral cavernous sinus. Partial removal of the le-sion was performed via the transsphenoidal route. The histopathological diagnosis of the mass was consistent with diffuse, medium sized cell, B-cell type malignant lymphoma. A postoperative systemic evaluation by tumor scan with 67Ga disclosed no abnormal uptake ex-cept in the skull base. Postoperatively, the patient was treated with radiation, a total of 50 Gy, followed by che-motherapy every 3 week consistent of cyclophospha-mide, vincristine, pirarubicin, bleomycin, procarbazine and prednisolone. The cranial nerve symptoms dis-appeared during radiation therapy. The MR studies after three courses of chemotherapy revealed almost complete remission. The patient died of acute progression of pneumonia without any evidence of the recurrence of malignant lymphoma 10 months after the operation. Skull base involvement of malignant lymphoma is un-usual. Five cases of malignant lymphoma invading the skull base have been reported since 1987. In most cases, the lesion originated from paranasal sinuses and was usually accompanied with intradural extensions. In the case we have reported there was no intradural inva-sion of the tumor. Although malignant lymphomas in the central nervous system are usually B-cell type, radiosensitive and of low grade malignancy, the pro-gnosis of the disease is poor. Systemic and planned chemotherapy was recommended for treating neurosurgi-cal malignant lymphomas.