Breast Cancer Recurrence in the Parotid Gland Eight Years Later

What happened, in summary

A 59-year-old woman sought evaluation for a painless lump behind the left angle of her jaw that had been present for eight weeks. Eight years earlier, she had been treated for a right-breast tumor consisting of a 33 mm grade III invasive ductal carcinoma with extensive ductal carcinoma in situ. The original cancer was staged T2N0M0, with negative sentinel nodes and clear surgical margins. It was estrogen-receptor positive and HER2-positive.

Her initial treatment included right mastectomy, six cycles of FEC-75 chemotherapy, chest-wall radiation to 50 Gy in 25 fractions, 18 cycles of trastuzumab over 12 months, and long-term anastrozole. Annual mammograms had not shown metastatic disease. The new parotid lump was first thought to be a benign pleomorphic adenoma and was excised. Pathology instead identified metastatic breast cancer. The parotid tumor was ER-positive, PR-negative, and HER2-positive, matching the breast-cancer history. Staging CT found no other distant disease.

Because the first excision had positive margins, she underwent a left parotidectomy with selective posterolateral neck dissection while preserving the facial nerve. All 32 removed lymph nodes were free of metastasis. Her endocrine therapy was changed from anastrozole to exemestane. Additional chemotherapy, radiation, and trastuzumab were not advised after complete removal of the isolated lesion. She recovered with normal facial function; a small salivary fistula and cheek numbness were managed conservatively. PET-CT one month later showed no significant abnormality.