Successful Neoadjuvant Treatment Using Trastuzumab Emtansine (Kadcyla) for Locally Advanced and Metastatic Lacrimal Gland Adenocarcinoma.

A 25-year-old man presented with a locally advanced lacrimal gland adenocarcinoma with parotid metastasis. The lesion was strongly HER-2 positive (3+) on immunohistochemistry. The patient was treated with neoadjuvant trastuzumab emtansine, an antibody-drug conjugate targeting HER-2. The patient had an excellent response to neoadjuvant therapy trastuzumab emtansine, with a significant decrease in the size of the lacrimal gland carcinoma, making eye-sparing surgery a viable option for the patient. Furthermore, there was nearly complete resolution of the parotid metastasis; thus, radical neck dissection and parotidectomy were avoided.