Helmut Lang cotton button down asymmetrical low back shirt

Size P - fits like XS Very bottom button is missing, but there is a spare button attached to the care tag. There are a couple tiny (pin-sized) stains on the back of the shirt at the very bottom (see photo). Approx. measurements laid flat: Pit to pit - 16.5” Length in front - around 23” Length in back - around 33”