Apparently, splenic haemangiomas are the commonest benign tumours of the spleen, and the majority are asymptomatic, being diagnosed as an incidental finding on investigative procedures
for other disorders so he may be right in terms
of it being the cause
of your episodic retching. I would imagine if it caused any bloating of your spleen and possible rupture, then you might want to have it removed, but of course you need to discuss this with a GI doc. You may want to seek a second opinion.