This is an organic version of a mathematical pattern known as a Voronoi Diagram.  It's a rather complex version of it, obviously created as a solid object for 3d printing.  Even with a sculpting application, the creation of this kind of complex object might be challenging.  I personally feel it would be harder to achieve with a sculpting application, rather than a capable polygonal modeling package.  I know it probably doesn't seem that way at first glance, but Voronoi diagrams have been a favorite area of topological exploration of mine for years.  I used to experiment with them all the time in 3dsmax, using a combination of modifiers, and Maxscript.  I have not had the opportunity or time to pursue shapes like this yet in Blender, but that's certainly on my radar.

That said, it's actually easy to achieve something very similar to this in Blender or any other full-featured modeling package, with the right direction and knowledge of the tools.  Blender Sushi has a wonderful example of how to achieve a very similar structure, using their proprietary Blender format.  Have a look at this page:

http://blendersushi.blogspot.co.uk/2012/07/vfx-voronoi-cage.html

Scroll down a little, and you'll immediately see a cube which very closely resembles the object in your photo, and they achieved it with Blender using the Blender Cell Fracture tool, and Skin Modifier.  They give a detailed, and nicely illustrated example of how to do it.  Keep in mind that Blender Sushi has a much different UI and hotkey setup compared to vanilla Blender, but the tools they use are all available for the standard Blender as well.

Following their guidance on that page should lead you in the right direction to achieving this very beautiful and complex object, and show you how to do the same effect on a variety of different shapes as well.  Good luck!

______________________________________

My Store
My Free Models
My Video Tutorials
My CG Animations
Instagram: @luxxeon3d
Facebook: https://www.facebook.com/luxxeon