Will spinal hemangiomas lead to low blood count?

Usually not: Hemangiomas are benign blood vessel tumors. Sometimes, if the tumors are quite large, blood platelets can get activated in these tumors and stick to the blood vessel walls. This can result in a low platelet count. Platelets are necessary for proper blood clotting. This problem is called kasabach merritt phenomenon and is actually quite rare. If it occurs, it could cause a bleening tendency.

Yes: Certain types of hemangiomas in CNS can cause low cell counts due to GI bleeding and anemia fro example blue rubber bleb nevus syndrome.