I was told a few years ago that i have what looks like a calcified hematoma in my spleen. is this dangerous? could it become a blood clot and hurt me

Hematoma=blood clot: The chance to get hurt by what is in your spleen was months to years ago, and likely due to a traumatic impact to your abdomen (but not only way), causing bruising / bleeding / hematoma (all same) within your spleen. You got better, but the blood did not rapidly reabsorb (like most bruises do), so body built a "fence" around it to protect itself...Using calcium. Should be stable.