Granular cell tumor of the breast: definitive diagnosis by sonographically guided percutaneous biopsy

Granular cell tumor is a rare, benign breast neoplasm that may mimic malignancy both clinically and radiologically. We present 2 cases in which granular cell tumor was initially diagnosed by sonographically guided percutaneous biopsies. Sonographic guidance confirmed needle placement during multiple passes and thereby decreased the likelihood of sampling error. A diagnosis of granular cell tumor prior to definitive resection enables optimal therapeutic planning and allows radical surgery to be avoided.