Epidermotropic metastases with trans-epidermal elimination from breast carcinoma.

Sir, Epidermotropic metastasis is an uncommon histopathological feature characterized by pagetoid spread of neoplastic cells in the epidermis. This special type of metastasis has been reported in several types of metastatic neoplasms, including malignant melanoma (1), eccrine porocarcinoma (2), squamous cell carcinoma (3), colon adenocarcinoma (4) and breast carcinoma (4, 5). On the other hand, trans-epidermal elimination, first described by Mehregan (6) in elastosis perforans serpignosa, is a specific mechanism whereby foreign constituents can be eliminated through the epidermis. This phenomenon has been observed in various benign or malignant cutaneous tumours, such as melanocytic nevus (7), eccrine poroma (8), malignant melanoma (9) and metastatic carcinoma (4, 5). We describe here a rare case of epidermotropic metastases with trans-epidermal elimination from breast carcinoma mimicking mammary Paget’s disease and discuss the mechanism of this phenomenon. In addition, we report a specific clinical appearance of the areas where the trans-epidermal elimination of the tumour cells occurred. To our knowledge, such clinical and histopathological features in cutaneous metastasis from breast carcinoma are exceptionally rare (5).