Trastuzumab for Her2/neu-positive metastatic salivary gland carcinoma: Case report and review of the literature
We are reporting a 62-year-old Caucasian male with a history of resected benign parotid gland tumor on 1985. After 22 years of resection, he presented with right kidney mass which was suspicious for renal cell carcinoma. He underwent right nephrectomy with a pathological diagnosis of renal cell carcinoma of unclassified histology. Afterward, the patient was enrolled in the adjuvant Econ 2805 study in the placebo arm; subsequently, he relapsed with retroperitoneal lymphadenopathy. Following this, the patient was started on sunitinib therapy, a receptor tyrosine kinase inhibitor, in 2009 for metastatic renal cell carcinoma, though patient's tumor continued to progress. He was sent to be evaluated for a phase-I trial; during the evaluation, multiple pathologists evaluated his renal tumor histopathology studies and core biopsies of the salivary gland resection were compared to his nephrectomy ones. They concluded that the renal tumor is a metastasis from the salivary gland carcinoma with adenocarcinoma features.\nSubsequently, the patient developed severe right upper quadrant abdominal pain. Follow-up diagnostic studies with positron emission tomography (PET) scan showed disease progression with multiple bilateral hepatic lesions and retroperitoneal lymphadenopathy [], with elevated liver enzymes. The tumor was tested for Her2/neu, which was strongly positive, +3 by IHC. Then, the patient was started on weekly trastuzumab (4 mg/kg loading dose, then 2 mg/kg maintenance) and paclitaxel 80 mg/m2.[]\nThe abdominal pain he was having and the elevated liver enzymes resolved after the first dose of trastuzumab and paclitaxel. After 6 weeks of treatment, diagnostic studies of the abdomen showed decreased size of the metastatic disease in the liver and retroperitoneal lymph nodes. The patient was continued on a maintenance weekly trastuzumab. Three months later, repeated scanning showed continuous response to therapy. Follow-up PET-scanning 1 year later revealed complete resolution of the previously seen liver lesions []. To date, the patient is alive, stable, and receiving weekly Trastuzumab.