Acinic cell carcinoma with lymphoid stroma mistaken for a metastatic intraparotid lymph node at frozen section analysis

Acinic cell carcinoma is a rare salivary gland tumor. The variant with lymphoid stroma is even rarer and has distinct histological features. We describe the case of a forty three year-old woman who presented with a left retroauricular mass of 5 years duration; magnetic resonance imaging revealed a well-circumscribed mass of 1.5 cm suggestive of pleomorphic adenoma. The patient underwent inferior polar parotidectomy. Frozen section analysis was performed and the interpretation of the sample suggested a metastatic intraparotid lymph node. The definitive final diagnosis of acinic cell carcinoma with lymphoid stroma was made on the basis of histological and histochemical findings, after a review of the literature.