The abdominal CT slice shows

a grossly distended suprapubic mass, which in this case was from hematometra. The urinary bladder with an indwelling catheter is seen at the right lower aspect of pelvis.

Teaching points-

1. Consider hematometra if you see a suprapubic mass in a menarcheal age group patient.
2. Revisit an initial diagnosis of urinary retention if ‘bladder distension’ persists after successful insertion of an indwelling catheter.