悪性リンパ腫によるparaneoplastic syndromeが疑われた外眼筋炎の1例

A case of ocular myositis as paraneoplastic syndrome due to malignant lymphoma

　悪性リンパ腫の患者に合併した両眼の外眼筋炎の1症例を報告した。症例は60歳女性で悪性リンパ腫で加療中，眼球突出，眼球運動障害が出現した。CTにて両眼の4直筋肥厚を認めたが眼球内や視神経への浸潤は認めなかった。そして，化学療法にて外眼筋の肥厚は消退し，症状も改善した。腫瘍細胞の外眼筋への直接浸潤では，片眼の単独筋への浸潤が多く，両眼へ浸潤している場合は眼窩，視神経，眼球内にも浸潤していることが多い。このため外眼筋の肥厚は悪性リンパ腫による遠隔効果，すなわちparaneoplastic syndromeであることが疑われた。

A 60-year-old female presented with bilateral exophthalmos with restricted ocular movement. She had been under treatment for malignant lymphoma since 3 years before. Computed tomography showed thickening of the four rectus muscles in both eyes and led to the diagnosis of ocular myositis. There were no infiltrations in the eyeball or the optic nerve. Systemic chemotherapy induced resolution of swelling in the rectus muscles and improved ocular movement. Direct infiltration of tumor cells in the extraocular muscles frequently occurs unilaterally. In the case of bilateral infiltration, the orbital tissue, optic nerve and the eyeball are also involved. The selective swelling of extraocular muscles in the present case was therefore interpreted as remote effect of malignant lymphoma, or paraneoplastic syndrome.