Canalicular Cyst.

PURPOSE To report a new entity discovered in the lacrimal drainage system, a congenital canalicular cyst (as opposed to a diverticulum or canaliculops). METHODS Clinical, radiographic, histopathologic and immunohistochemical findings were reviewed. RESULTS A 49-year-old man developed a left upper eyelid cyst seen by CT scanning to be attached to a small boney spicule. No connection to the lacrimal sac or canaliculus was discovered during surgical excision. Histopathologically, the cyst was lined mostly by canalicular epithelium, expressing a cytokeratin profile similar to that of a normal canaliculus and canaliculops. CONCLUSION This case increases ophthalmologists' appreciation of the range of conditions that can affect the lacrimal drainage and canalicular system. The treatment for a diverticulum is marsupialization, whereas that for a canalicular cyst is complete excision.