Superior gluteal artery pseudoaneurysms are uncommon with the main causes being trauma and iatrogenic. They have been treated by coil embolization, open surgery, or thrombin injection. A 36-year-old female with leucocytosis underwent bone marrow biopsy following which she developed pain and left lower limb weakness. Magnetic resonance imaging showed hematoma in the left pyriformis muscles probably compressing the sciatic nerve. A computed tomography angiogram confirmed a left superior gluteal artery partially thrombosed pseudoaneurysm which was subsequently treated by coil embolization. A high degree of suspicion of this complication early imaging and management can prevent significant blood loss and mortality.