成人発症の単発型眼窩部ランゲルハンス細胞組織球症の1例

A Case of Unifocal Orbital Langerhans Cell Histiocytosis in an Adult

Ⅰ．はじめに

　ランゲルハンス細胞組織球症（Langerhans cell histiocytosis：LCH）は，以前はhistiocytosis X，eosinophilic granuloma，Letterer-Siwe病，Hand-Schüller-Christian病などと呼ばれた疾患の総称である．主に1～3歳に好発し，小児における年間発症率は100万人に5人前後とする報告が多く^2,13)，成人発症例はさらに少ないとされる⁹⁾．病的なランゲルハンス細胞が異常増殖する非腫瘍性の疾患で，全身に病変が生じ得る可能性があるが，骨病変の頻度が最も高く，なかでも頭蓋骨に生じることが多い⁹⁾．現在では，罹患する臓器と病変の数により，単一臓器単発（single-system single-site：SS）型，単一臓器多発（single-system multi-site：SM）型，多臓器病変（multi-system multi-site：MM）型と分類される．

　今回，われわれは成人発症の眼窩に発生したLCHを経験したので報告する．

　A 34-year-old man had a 3-month history of left upper eyelid swelling and pain. Computed tomography showed osteolytic lesion of the left frontal bone. Magnetic resonance imaging (MRI) revealed a mass lesion with heterogeneously gadolinium enhancement and extension to both the lateral orbit and the frontal base. We performed mass resection via left frontotemporal craniotomy to diagnose the lesion. Pathological findings of the specimen were Langerhans cell histiocytosis (LCH). Systemic investigations revealed no sign of the disease elsewhere. The patient was diagnosed with unifocal orbital LCH and received neither chemotherapy nor radiotherapy. Follow-up MRI has shown no recurrences 2 years after surgery. Although orbital LCH rarely occurrs in adults,it should be considered in differential diagnosis of orbital tumor. The patients with unifocal orbital LCH required no treatment in addition to mass resection.