But collecting a bunch of promotional pens wasn't really something Dr. Caren ever set out to do.
Over a decade ago, pharmaceutical companies had a common practice of giving away pens and other branded items to encourage sales of their products. Dr. Caren noticed that each pen was dramatically different in design.
"I decided to make a little fun of the process," he says.
Soon he made it clear to pharmaceutical reps that he wouldn't meet with them unless they brought in a pen. The representatives complied and Dr. Caren soon had to modify the rule—they had to bring in a pen he didn't already have.
"They started scrambling," says Dr. Caren. "They knew they couldn't come in here without a fresh pen."
The writing implements, he proudly notes, are all in mint condition.
"They've never been written with by human hands," he says. "At least not in my custody."
Swag becomes art
The pens' pristine beauty is on permanent exhibit in his office. About 600 pens are in a transparent case affixed to an office pillar.
He and his wife bought the case and devoted a weekend to carefully gluing each pen inside it. Now he can't imagine his office without his pen pillar and jokingly refers to the collection as "industrial art."
In all, Dr. Caren estimates he collected more than 1,200 pens before the pharmaceutical industry stopped distributing the branded items to physicians in 2009.