Abstract
BACKGROUND: Tumor deposits are irregular clusters of tumor cells in adipose tissue, discontinuous from the primary tumor. While their prognostic relevance has been well established in colorectal and gastric cancers, their significance in breast cancer remains poorly understood. This case highlights the presence of tumor deposits in breast cancer, with focus on their potential prognostic implications as well as the need for clearer diagnostic criteria. CASE PRESENTATION: We report the case of a 58-year-old Tunisian woman who presented with a 2-cm breast nodule. Clinically, the lesion was staged as T4bN0Mx, and imaging classified it as American College of Radiology category 5. Fine needle biopsy revealed an invasive grade III breast carcinoma according to the Scarff-Bloom-Richardson grading scale. The patient received hormone therapy, radiotherapy, and neoadjuvant chemotherapy followed by mastectomy with axillary dissection. Histopathological examination of axillary adipose revealed 14 tumor deposits and five metastatic lymph nodes with extracapsular extension. The pathological response to chemotherapy was poor, with more than 50% residual tumor. The patient is currently in good condition and is receiving hormone therapy. CONCLUSION: Although tumor deposits are correlated with poor prognosis in other cancers, particularly in colorectal and gastric cancer, limited data are available for breast cancer. Owing to the unclear diagnostic criteria, they are often considered as lymph node metastases. To address this issue, we recommend reporting tumor deposits, and we encourage further studies on larger cohorts to better define their prognostic value and eventually, discuss their inclusion in the tumor, node, metastasis staging system.