Spindle Cell Tumor

My 40 year old girlfriend had a tumor removed a month ago and just found out yesterday it was a spindle cell tumor.  She was told it was not cancerous.  Does anyone know if all Spindle Cell Tumors are cancerous?  (I read online that all spindle cell tumors are cancer). She is scheduled next week for the Dr. to return to the original tumor site (very nearto the clitoris) and remove cells surrounding where the tumor was. 

Additional information:   She also had an ovary removed as a young teen due to early development and a growing cyst.  She also has had many repeat mammograms for abnormal / pre calcifications.  Any info would be greatly appreciated.