JK Chung, et al. SUDORIFEROUS CYST ACCOMPAINED WITH ESOTROPIA Fig. 1. (A) A round palpable pinkish lump on left upper lid with limitation of eye opening due to the mass. (B) Three dimensional reconstruction of orbit MRI. (C) An orbit ultrasonography shows well circumscribed, round, anechogenic cyst (left) and the left globe is displaced to posterior lateral portion and compressed by the mass (right). (D) Orbit MRI. A 1.4×1.3 ㎝ sized circumscribed, round, cystic mass in medial superior aspect in left orbit. Eye ball is displaced to the inferior posterior portion with intact optic nerve and the mass shows low signal intensity on Gd-DTPA enhancement sagittal T1WI. flattened epithelium, with features identical to the glands of Moll. The innermost cells displayed a granular and distinctly eosinophilic cytoplasm with apical expansions, while the outer wall was composed of a fibrous tissue. The diagnosis of a sudoriferous cyst was thus confirmed (Fig. 2C). The patient underwent a comprehensive ocular examination one week after the operation. Since there appeared to be little fixation or following efforts towards the mother's face or a hand at near distances with the left eye, the patient was prescribed 30 minutes of occlusion by patch per day. Esotropia was then able to be diagnosed. The angle of deviation was 30 prism diopters (PD) by the Krimsky method. Even with intensive occlusion therapy, examination at four months showed no interval change for fixation and an abduction limitation on left eye was found. Seven months after the operation, occlusion therapy was ceased because of a newly developed poor response to visual stimulation on the right eye, probably due to occlusion time in excess of the prescribed treatment. The angle of deviation was then found to be 50 PD by an alternative prism cover test at a near distance. US revealed no abnormal echogenecity in the left orbital area and no movement during scanning on the left eyeball which was deviated medially (Fig. 3A). Nine months after the operation, 30 PD esotropia was determined by the Krimsky method and an abduction limitation was found in both eyes (Fig. 3B). Computed tomography (CT) of the orbits revealed no eyeball deformity with normal extra-ocular muscle structure and normal peri-orbital tissue (Fig. 3C). D iscussio n Sudoriferous cysts, also known as apocrine gland cysts and apocrine hydrocystomas are derived from the sweat glands of Moll. They probably result from the obstruction of excretory ducts with the retention of clear fluid.1,3 They are divided into two types, apocrine and eccrine, and represent 4~5% of all eyelid tumors in adults and 1% in children, but are less common in the orbit itself. Symptoms appears as fluctuant swelling beneath the eyelid or in the canthal area.1,3,4-7 Shields and Shields1 reported that it is probably not possible to differentiate a small cystic lesion without bone involvement from other orbit cysts even with a CT or an MRI. However, Rosen and Li8 reported sudoriferous cysts in adults and associated bony remodeling of the inferior orbit 121