Granular cell tumour (GCT) is a rare, usually benign neoplasm that can mimic carcinoma on breast imaging. GCT can originate anywhere in the body but is most frequently found in the head and neck region, particularly in the tongue. Of the reported cases, 6% have occurred in the breast, most commonly in the upper inner quadrant. We report a case of GCT of the breast presenting as a spiculated mass infiltrating the greater thoracic muscle on breast screening mammogram.