[Sonographic diagnosis of congenital dacryocystocele]

Congenital obstruction of the nasolacrimal drainage system occurs quite commonly. The reason is usually an impaired canalization at the distal end of the nasolacrimal duct with a residual membrane between the duct and the nasal cavity. Dacryocystocele is believed to result from a concomitant upper and lower system obstruction, causing fluid accumulation and distension of the lacrimal sac. The patient presents at birth with a tense, blue-grey swelling located just below the medial canthal tendon. The differential diagnosis for dacryocystocele includes haemangioma, encephalocele, glioma, dermoid cysts and malignant processes.

We demonstrate five typical cases to describe the sonographic features of dacryocystocele.

Ultrasound is a simple, straight forward and gentle method to reliably distinguish dacryocystoceles from other pathologies. A sedation of the patient is not necessary. The sonographic appearance of a cystic mass medial and inferior of the orbit communicating with the dilated nasolacrimal duct as well as the typical content of fluid and debris was diagnostic of a nasolacrimal mucocele or dacryocystocele. Other more invasive imaging techniques as CT-scans and MRI are of benefit only if there is any doubt about the diagnosis.