Diagnostic utility of bony nasolacrimal duct area on computed tomography for differentiating malignant lacrimal tumors.

The malignant tumor group included 12 males and 7 females, and the mean age was 54.7 years.

The benign mass group included 7 males and 7 females, and the mean age was 67.5 years.

The primary acquired nasolacrimal duct obstruction group included 39 males and 142 females, and the mean age was 70.3 years.

Median expansion ratios of the bony nasolacrimal duct (affected side/unaffected side) on axial computed tomography were 167.5% in the malignant tumor group, 123.3% in the benign mass group, and 106.8% in the primary acquired nasolacrimal duct obstruction group.