診断が困難であった両側眼窩MALTリンパ腫の1例

A case of orbital MALT lymphoma with diagnostic difficulties

要約　目的：6年の経過中，数回の病理診断で炎性偽腫瘍と診断され，後にMALT（mucosa-associated lymphoid tissue）リンパ腫の診断が確定した両側眼窩腫瘍の1例の報告。症例：70歳女性が2か月前からの両側の眼球突出と視力低下で受診した。43歳のときに下垂体腺腫，3か月前に皮下のリンパ組織過形成の既往がある。画像診断で両側の眼窩内に腫瘤があり，生検で肉芽組織と診断された。経過中2回の視力低下と眼球突出の悪化があり，プレドニゾロン内服で改善した。生検で炎性偽腫瘍と診断されたが，病理組織の再検討で，MALTリンパ腫と診断された。抗CA20抗体療法などで，初診から6年後の現在まで右眼視機能を維持している。結論：MALTリンパ腫とその類縁疾患では，確定診断が困難であることを理解し，臨床経過を慎重に追うことと，入念な組織の検討が重要である。

Abstract.　Purpose：To report a case of mucosa-associated lymphoid tissue（MALT）lymphoma who was repeatedly diagnosed, by biopsy, with inflammatory pseudotumor of orbit. Case and Findings：A 70-year-old female presented with bilateral proptosis and blurring of vision. She had had pituitary tumor at the age of 43 years. She had been diagnosed with hyperplasia of subcutaneous lymphatic tissue 3 months before. Diagnostic imaging showed tumorous mass in both orbit. The tumor was identified as granuloma by biopsy. Two episodes of visual failure and progression of proptosis were controlled by peroral prednisolone. After repeated diagnosis of inflammatory pseudotumor of orbit, review of pathological specimen led to the final diagnosis of MALT lymphoma. She has been doing well by anti-CA 20 treatment during 6 years after her initial visit. Conclusion：MALT lymphoma may pose difficulties in diagnosis. Suspected cases need close clinical follow-up and examination of pathological specimens.