Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Volcano (VOLC), a medical device maker of products used to diagnose and treat vascular and structural heart diseases, gushed lower by as much as 16% after reporting its fourth-quarter earnings results.

So what: For the quarter, Volcano reported revenue growth of 10% to $102.5 million and a GAAP profit of $0.04, down considerably from the $0.54 in GAAP EPS reported in the year-ago period. Wall Street expectations had been calling for a profit of $0.09 on revenue of $102.1 million. More damaging, however, was Volcano's 2013 guidance, which calls for a profit of $0.08-$0.11 on $406 million to $412 million in revenue. This is considerably lower than the $0.29 in EPS and $423.5 million that the Street had been projecting.

Now what: What's even more bizarre about Volcano's guidance is that the company had to issue a second press release essentially updating its 2013 guidance, because the forecast in its initial earnings release was given on a "constant currency basis." Talk about all the different ways you could anger investors and analysts in a 24-hour period! I'm pretty sure investors have some major questions as to why Volcano's EPS is nowhere near expectations, and I personally have concerns about the potential for product delays if the figures are this far off. I'm perfectly fine adding Volcano to my watchlist, but I'd suggest steering clear until management gets its act together.

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