Radiographic visualization of congenital lacrimal sac mucoceles

The clinical presentation of a congenital mucocele is a blue-gray tense mass located inferior to the medial canthal ligament. The differential diagnosis is that of tumor and encephalocele. Diagnostic modalities such as simple transillumination and ultrasound aid the physician, but dacryocystography confirms the marked lacrimal sac distension. In three infants the sac could not be decompressed by massage, indicating that the canalicular-punctal system as well as the inferior lacrimal system were blocked. When the distended lacrimal sac compresses the two canaliculi and bends them on themselves, there is a functional trapdoor-type block. During the probing of these patients, we felt a snap when the lacrimal syringe was withdrawn from the distended sac. We concluded that this was due to kinking of the canaliculus by the enlarged sac.