A woman in her 60s presented to her primary care physician with a right-sided lower motor neuron facial nerve palsy. This resolved with oral steroids and antiviral drugs consistent with a presumed diagnosis of idiopathic facial nerve (Bell) palsy. Six months later the patient developed discomfort around her right ear, prompting a referral to the local otolaryngology service. Her medical history was significant for localized invasive ductal carcinoma of the right breast treated with wide local excision 13 years previously. At presentation she was considered disease-free. Findings from the clinical examination, including otoscopy, were unremarkable. A magnetic resonance imaging (MRI) scan revealed an 8-mm lesion within the right parotid gland with a spiculated border and ill-defined surrounding enhancement extending close to the stylomastoid foramen (Figure, A). This was of low T2 signal with no perineural spread evident. A fine-needle aspirate and core biopsy were obtained under ultrasonographic guidance. The cytologic findings showed loosely cohesive groups of atypical epithelial cells. Histologic examination of the core biopsy revealed an infiltrative lesion composed of cords and nests of medium-sized cells surrounded by a densely hyalinized stroma (Figure, B). The cells contained hyperchromatic vesicular nuclei with moderate amounts of eosinophilic cytoplasm (Figure, C). Immunohistochemical analysis showed the cells were diffusely positive for cytokeratin 7 (CK7), estrogen receptor (ER), progesterone receptor (PR), and androgen receptor (Figure, D).
Burgess CA, Foden NM, Winter SC. A Lesion in the Parotid Gland. JAMA Otolaryngol Head Neck Surg. 2015;141(9):845-846. doi:10.1001/jamaoto.2015.1412