A rare case of retroauricular Warthin's tumor in a 46-year-old man

A 46-year-old Taiwanese man presented with a 4-month history of a slow-growing mass in the right retroauricular area (Figure 1). The asymptomatic, ill-defined, movable, soft, skin-colored subcutaneous nodule had a mild central depression. Apart from a 20year habit of smoking 20 cigarettes/day, his medical historywas unremarkable. An incisional biopsy under the clinical impression of an epidermal cyst was performed to confirm tumor diagnosis because of the large size of the mass. Results of a histopathological examination revealed hyperkeratosis, acanthosis with marked dermal and subcutaneous fibrosis with a small upper portion of a cystic tumor at the deep surgical margin. The cystic tumor was lined by oncocytic epithelial cells with lymphoid and plasma cells in the stroma (Figure 2). The epithelial wall was composed partly of squamous epithelial cells and partly of columnar epithelial cells with mucinous cells. The patient was then referred to the Otolaryngology department where a computed tomography scan without contrast was arranged. A 28-mm solitary mass lesion with interior cystic changes and mild heterogeneous enhancement was found in the inferior, superficial portion of the right parotid gland (Figure 3, arrow). A right partial parotidectomy with facial nerve dissection was performed. The cut surface of the 2.5-cm well-circumscribed nodule showed white firm cystic change. No recurrence was noted at 3year follow-up. The histopathological findings confirmed the diagnosis of a Warthin’s tumor (WT, which is descriptively referred to as papillary cystadenoma lymphomatosum). The WT was first described by Aldred Scott Warthin in 1929.1 The descriptive term for WT is papillary cystadenoma lymphomatosum. The WT is the second most common benign salivary gland tumor representing approximately 2–15% of all parotid tumors after pleomorphic adenomas. A WT is usually unilateral and almost exclusively originates in the parotid gland, which is wrapped around the mandibular ramus. Only approximately 10% of such tumors are bilateral.2 Although cases of WT arising outside the ordinary region of parotid gland are rare, there have been reports of WT originating in the submandibular gland, larynx, lower lip, palate, and even in the buccal fold.3 Most of these tumors occur in patients between the 5th and 7th decades of life, and there appears to be a predilection in males. Smoking has been strongly associated with the tumor with smokers having eight times more risk of developing the tumor than nonsmokers. Although its pathogenesis remains unknown, many