Granular cell tumour of the breast in a young female: A case report and literature review.

A granular cell tumour (GCT) of the breast is a relatively uncommon lesion. Often, it mimics carcinoma on clinical and radiological examinations. The striking feature of GCT is the presence of abundant granular eosinophilic cytoplasm, which can easily lead to a misdiagnosis of apocrine carcinoma or a metastatic lesion and may result in unnecessary surgery. To obtain a correct diagnosis, immunohistochemistry with S100 is required. We present a case of a GCT of the breast in a 19-year-old female who presented with a firm mass in the upper inner quadrant of the left breast, which was reported on a mammogram as the Breast Imaging Reporting and Data System (BIRADS) Category 4C. This report is of interest due to the young age of the patient and the rarity of the lesion. To our knowledge, this is the second reported case in all of Saudi Arabia and the first from the Madinah region.