Polymorphous low-grade adenocarcinoma of the upper lip with metachronous myoepithelioma of the buccal mucosa

Abstract

Examples of multiple minor salivary gland tumors, synchronous or metachronous, are uncommon. We report a patient who initially presented with polymorphous low-grade adenocarcinoma (PLGA) and subsequently with myoepithelioma. A 91-year-old white woman presented in 2009 with a 1-cm, firm, nontender, well-circumscribed nodule of the left side of the upper lip extending to the anterior buccal mucosa. Excisional biopsy revealed PLGA. While the margins were positive, further treatment was not recommended due to the patient's age. In 2011, the patient returned with a 1.5-cm, asymptomatic mass of the left buccal vestibule. Excision of the lesion revealed a circumscribed proliferation of epithelioid and plasmacytoid cells arranged in spherical or whorl-like islands and immersed in a mucinous stroma, consistent with myoepithelioma. The PLGA recurred 3 years after initial diagnosis. Excision was again associated with positive margins, and again no further treatment was recommended. A few months later, at a scheduled follow-up appointment, she presented with a painless nodule of the left upper lip, consistent with recurrent PLGA. One month later, the patient died of unrelated causes. We also present a literature review of multiple minor salivary gland tumors.