Pathology Quiz Case 1

A 44-YEAR-OLD MAN PRESENTED WITH A 6-month history of a slow-growing, tender mass anterior to his left ear. His medical history was remarkable for hypertension and hyperlipidemia. He also had a 7 pack-year smoking history. He denied any previous infections, trauma, otalgia, fevers, chills, night sweats, unexpected weight loss, or other constitutional symptoms. The findings of the physical examination were normal with the exception of a 0.5-cm, firm, mobile, tender, superficial mass anterior to the left tragus. Facial movement was symmetrical bilaterally. There was no evidence of adenopathy. An ultrasonogram showed a 1 1-cm oval mass within the substance of the left parotid gland. After completion of a 2-week course of amoxicillin-clavulanate, without improvement, fine-needle aspiration (FNA) was performed, the results of which were nondiagnostic. Computed tomography of the neck with contrast revealed a 1-cm hyperdense nodule within the left parotid substance and fatty replacement of the left parotid gland (Figure 1). A superficial parotidectomy, which was performed through a facelift incision, demonstrated a wellcircumscribed, soft, pink-tan nodule, measuring 1.3 cm in greatest dimension. Hematoxylin-eosin (H&E)stained sections exhibited a nodular circumscribed lesion composed of variably sized cystic spaces with associated sclerotic collagenous tissue with normalappearing salivary gland tissue along the periphery (Figure 2). A high-power H&E-stained section revealed cells with classic apocrine metaplasia demonstrating decapitation secretion (Figure 3). Brightly staining eosinophilic zymogen granules of variable sizes were evident at the center of this H&E-stained section (Figure 4). What is your diagnosis?