Maybe some kind of Jatropha? Has it never bloomed? Probably needs more light.

Possibly an Uncarina, like Uncarina roeoesliana? Many caudiciforms need to be cut back to keep them shapely and continue to grow the caudex. Full sun outside during the summer with lots of water. Dry winter rest. And every few years cut back all the way. The new growth is a perfect opportunity to cut off the tall growth all the way down to the new growth.

you cant take a plant that has been indoors for 10 years and stick it out in full sun ... without properly hardening it off to such ...

but if you were to cut it down to just above where the new shoot is.. then it wont have any leaves to sunburn.... so you might get away with it ...

and since you will have a big piece ... see if you can propagate/root small pieces .. and start new .. and if you do that .. then i would just throw out the old plant ... since you cutting are the old plant .. you arent losing the plant ...

if its not obvious.. it is severely pot bound ... and i wonder if there is actually any potting media in that pot ... which means you probably have watering issues [especially if you put it out in full sun] .. which is probably why the leaves are so off color.. if not for all the accumulated salts in the old media ...

ken

It’s a caudiciform. Value comes from an Old thick basal trunk. You should never throw away the old plant, even if you do root a new one. Uncarina are also notoriously difficult for rooting. It does not look pot bound at all. Caudiciforms usually like to be a bit heavy rooted in their pot. Cut off the top and throw that away. Stick it in full sun and grow the fattest trunk you can.

Thank you to macranthos - you are 100% right! Looking at pictures of the Uncarina roeoesliana, that is exactly my plant, but I have never seen it flower. I'll take your advice and try cutting it back. I'm nervous about it but it seems like the right move. Thanks for the help!