Multilobular lacrimal sac diverticulum presenting as a lower eyelid mass

Lacrimal sac diverticulum is a rare condition, and its various symptoms complicate differential diagnosis. We present cases of a peculiar type of lacrimal diverticulum. A 5-year-old girl and a 50-year-old woman presented with a protruding mass inferior to the medial canthus. Each lacrimal system was patent to irrigation. The masses compressed and distorted the lacrimal passage and had no apparent connection with the lacrimal sac in dacryocystography or computed tomography. Surgical exploration and complete excision of the masses were completed. Each patient had an inverted Y- and an inverted V-shaped multilobular cystic mass that was pathologically confirmed as a lacrimal sac diverticulum. Lacrimal sac diverticula may rarely take the form of a multilobular cyst and can present as a lower lid mass. We speculate that an abnormality in lacrimal embryogenesis resulted in multiple blind pouches, a peculiar type of lacrimal sac diverticulum.