Gou ZC, et al. - Experts assessed the clinicopathological characteristics and prognostic features of carcinoma of the axillary tail of Spence (CATS) (a poorly studied type of breast cancer). They identified patients diagnosed with upper outer quadrant breast cancer (UOBC) or CATS using the Surveillance, Epidemiology, and End Results database. Distinct clinicopathological characteristics were demonstrated in CATS and there was a greater likeliness of it being associated with lymph node (LN) metastasis. Adverse impacts of CATS were seen on breast cancer-specific survival (BCSS) vs upper outer quadrant breast cancer (UOBC).