What is the most common pathology of lacrimal sac?
Dacryocystitis due to nasolacrimal duct obstruction.
Cystic distention of left side lacrimal sac and thickening of the wall of the sac, widened left side nasolacrimal duct, eyelids and preseptal soft tissue swelling, and fluid and thick mucosa in left side ethmoid and maxillary sinuses are seen. Note the minimal irregularity of the left orbit upper medial wall which can be due to previous trauma and deformity. Soft tissue swelling of right side preseptal is also seen.