Imaging features of multimodal ultrasound and dynamic contrast-enhanced MRI in breast granular cell tumor: A case report

Granular cell tumor of the breast (GCTB) is a rare benign lesion that constitutes a well-recognized diagnostic pitfall owing to its potential to simulate malignant breast neoplasms on imaging. We present a 50-year-old woman with a palpable, painless breast mass demonstrating relatively well-defined borders on imaging. Multimodal ultrasound was highly suspicious for malignancy, whereas dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) favored a benign process. Core needle biopsy with immunohistochemistry established the diagnosis of benign GCTB. This case highlights that GCTB may closely mimic breast cancer on ultrasound, which can lead to misdiagnosis and unnecessary overtreatment. For radiologists, recognition of this diagnostic pitfall is critical: ultrasound features suggestive of malignancy do not reliably exclude GCTB. A multimodal imaging approach, supplemented by targeted core needle biopsy and immunohistochemistry, is essential to avoid misinterpretation and establish the correct diagnosis.