Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
Acute pseudodacryocystitis is inflammation of the lacrimal sac secondary to anterior ethmoidal sinusitis and is unlike acute dacryocystitis, which is inflammation secondary to an obstructed lacrimal system. It is important to differentiate these etiologies, as the surgical treatment of choice for pseudodacryocystitis is anterior ethmoidectomy rather than dacryocystorhinostomy. In our case, plain axial CT shows a low density abnormality consistent with an abscess in the region of the swollen lacrimal sac (A, yellow arrow), with associated sinusitis in the adjacent anterior ethmoidal air cell (A, red arrow). The lacrimal bone on the left side is likely eroded on the bone window settings (B, arrow). Additional sinusitis of the left maxillary antrum is noted.