脊髄ダンベル型神経鞘腫と鑑別を要した神経梅毒に伴う多発性脊髄硬膜内外肉芽腫の1例

Multiple Spinal Intradural and Extradural Syphilis Granuloma Mimicking Lumbar Dumbbell Type Neurinoma:A Case Report

Ⅰ．はじめに

　梅毒はTreponema pallidum（Tp）による性感染症の代表的な疾患である．特に神経梅毒は，脳神経，髄膜，中枢神経，末梢神経，血管などあらゆる部位に症状を来す．今回われわれは梅毒に罹患した非HIV患者の脊髄ダンベル型腫瘤に対して脊髄神経鞘腫を疑い摘出術を施行し，術後の髄液検査で神経梅毒による肉芽腫と診断された症例を経験した．本邦では神経梅毒の症例は稀であるが，脊髄病変の鑑別としてその特徴を知ることは重要と思われるため，文献的考察を加えて報告する．

　Spinal intradural and extradural syphilis granuloma is extremely rare. Here, we report a patient with multiple spinal intradural and extradural syphilis granuloma mimicking dumbbell type neurinoma. The patient was a 68-year-old man, who presented with left femoral pain for a month. Magnetic resonance imaging（MRI）revealed a homogeneous enhanced dumbbell-shaped lesion occupying the spinal canal at the level of lumbar 3/4 and developing through the intervertebral foramen. Although initial blood tests revealed that he contracted with the syphilis, we diagnosed dumbbell type neurinoma preoperatively. He underwent partial tumor removal. The tumor adhered tightly to the cauda equina in intraoperative finding. Histopathological diagnosis of the lesion was granulomatous inflammation with the lymphocytic infiltration. Postoperatively, results of the Treponema pallidum hemagglutination（TPHA）test and the rapid plasma regain（RPR）test of cerebrospinal fluid were reactive, so we confirmed syphilis granuloma. He was treated with penicillin G for two weeks from 25 days after surgery. A follow-up MRI of the lumbar spine 51 days after surgery showed a reduction in size of the lumbar spinal tumor compared to the initial findings. Thus, syphilis granuloma should be considered in differential diagnosis of a spinal dumbbell shaped lesion. Penicillin G may be effective for the treatment of syphilis granuloma.