The peau d'orange appearance in advanced breast carcinoma is caused by lymphatic obstruction due to tumor infiltration in the dermal lymphatics. This leads to edema of the skin and tethering of hair follicles, resulting in a characteristic orange peel texture. It is a hallmark sign of locally advanced breast cancer and indicates extensive lymphatic involvement. Early detection of this feature is crucial as it suggests a poor prognosis and the need for more aggressive treatment. Other options like Virchow’s node enlargement are related to metastatic spread but not a direct characteristic of the advanced primary tumor skin changes.

Reference: Bailey & Love’s Short Practice of Surgery, 27th Edition.