Background The lacrimal ductal cyst (dacryops) is an uncommon clinical entity. It occurs anywhere that lacrimal gland tissue is present but most often appears as an expanding mass in the region of the lacrimal gland. The presence involving the medial part of the orbit is rare, ectopic location can be misleading in the differential diagnosis of orbital masses. The authors report a 53-year-old man who presented with dacryops occurred in an unusual location with significant clinical presentations. Case presentation A 53-year-old man had a painless mass located in the right superomedial orbit accompanied with foreign body sensation and lachrymation for two months, which had rapidly grown within 10 days. Decrease of visual acuity, high intraocular pressure (IOP) and limitation of extraocular movements in the right eye were present. The result of visual evoked potential (VEP) test suggested the impaired function of the optic nerve. Magnetic resonance imaging (MRI) studies revealed the presence of an isolated cystic lesion. The mass was completely removed via a transcutaneous approach, histopathologic findings were consistent with the lacrimal ductal cyst. The ocular motility and high IOP returned to normal. There had been no post-operative complications or signs of recurrence over five months follow-up. Conclusion Lacrimal ductal cysts can present in the medial orbit, clinicians should include this entity in the differential diagnosis of orbital masses and be aware of its variable presentations such as high IOP in this case. We comment on the fact that many reported cases of ectopic dacryops may be an extension of normal lacrimal gland tissue.