VTG Vintage Elan Men's Stretchy Button Up Shirt

This vintage navy blue button down shirt by Elan is stretchy and comfortable! Great for work or any casual to business-casual occasion! There is faded silver Sharpie on the tag, otherwise no flaws or damage. No size tag is on it, but it's 20" across at underarms, so I'd say it's a medium. I have no idea how old this shirt is.