孤立性頭蓋骨腫瘤を形成し硬膜下へ伸展した多発性骨髄腫の1例

Multiple Myeloma Presenting with a Solitary Cranial Tumor with Subdural Extension: A case report

I．はじめに

　多発性骨髄腫が頭蓋骨病変で発症することは稀であり，さらにpunehed out lesionではなく頭蓋骨円蓋部に孤立性の腫瘤を形成することは非常に稀である．そしてそのような腫瘍が硬膜下まで伸展することは極めて稀であり，われわれが検索し得た限り，現在までに1例も報告されていない．今回われわれは孤立性の前頭部腫瘤として発症し，腫瘍が前頭骨を中心に頭皮下から硬膜下腔に伸展していた多発性骨髄腫の1例を経験したので，文献的考察を加え報告する．

We report a case of multiple myeloma presenting with a solitary cranial tumor in the frontal region, extending from subcutaneous tissue to subdural space. To our knowledge, invasion of a tumor beyond the dura mater has never been described in cases of multiple myeloma presenting with a solitary calvarial tumor. In the present case, the subdural extension was clearly visualized by several diagnostic means.

A 53-year-old female patient visited the clinic of our University Hospital, complaining of a left frontal mass in May 1991. The mass grew rapidly, and she was hospital-ized in June. On admission, neurological examination showed nothing abnormal. Laboratory studies showed normocytic normochromic anemia. Protein elec-trophoresis disclosed hypergammaglobulinemia with S-spike, and serum paraprotein was specific to IgA with A light chains by immunoelectrophoresis. Urinary Bence-Jones protein was not detected. An osteolytic lesion visualized in the frontal bone on plain skull radiographs showed destruction of the frontal bone, and an enhanced mass extending from the epidural to subcutaneous space was shown by computed tomography. The mass had compressed the frontal lobe. T1-weighted magnetic reso-nance images of the area showed isointensity signals, homogeneously enhanced with gadolinium-diethylene-triamide pentaacetic acid. Subdural extension in the deep area of the tumor was suggested. At operation, we con-firmed infiltration of the tumor from the dura mater into the subdural space. Postoperative biopsy of bone mar-row of the iliac bone demonstrated myeloma cells. The tumor was histologically diagnosed as plasmacytoma. The patient was highly resistant to postoperative com-bined therapy, and started on a fatal course leading to re-spiratory insufficiency caused by interstitial pneumonia in April 1992.

This valuable case has been discussed and we wish to record it in medical literature as a reference case.