좌측 하직근을 침범한 점막연관 림프조직형 림프종 1예

Abstract

Purpose: To report an unusual case of mucosa-associated lymphoid tissue (MALT) lymphoma localized to the left inferior rectusmuscle. Case summary: A 52-year-old male presented with double vision 6 months in duration, which was exacerbated in thedown-gaze. On initial examination, 6 and 30 prism diopters (PDs) of left hypertropia were observed in primary gaze and downgaze, respectively. Prominently limited infraduction was also observed in his left eye. Computed tomography (CT) revealed contrastenhancing mass on the left inferior rectus muscle. He was diagnosed with suspicious orbital pseudotumor and treated withsystemic steroid for 2 months. Double vision and limited infraduction was improved and the mass size was decreased on CT. After 21 months, the patient revisited the clinic with the same symptoms. In the down-gaze, 35 PDs of hypertropia were observedin his left eye along with limited infraduction. CT revealed an enlarged mass and left superior rectus muscle recession along withan incisional biopsy of the left inferior rectus muscle were performed. Infiltration by small lymphoid cells was detected with hematoxylin-eosin and immunohistochemical stainings. Subsequently, the patient was diagnosed with MALT lymphoma localized tothe left inferior rectus muscle. Conclusions: This is the first description of MALT lymphoma with inferior rectus muscle invasion in a Korean patient. In a patientwith strabismus and limited duction, the possibility of extraocular muscle tumor including lymphoma should be considered. Homogenously contrast-enhanced mass on orbit CT can help in to make a diagnosing extraocular muscle lymphoma.