Primary Parotid Gland Lymphomas

Objectives: 1) Describe our experience in the diagnosis and management of the parotid gland lymphomas. 2) Present a rare case of synchronous MALT lymphoma of the parotid and high- grade non-Hodgkin lymphoma of the breast (DLBCL). Primary lymphomas of the salivary glands are rare, consisting less than 5% of all cases of extranodal lymphomas and about 2%-5% of salivary gland neoplasms. The most common subtype in the parotid is marginal zone B-cell mucosa-associated lymphoid tissue type lymphoma (MALT). Methods: We retrospectively reviewed the histopathologic reports of 251 parotidectomies that were performed in our department during the last decade. All patients presented with parotid gland swelling and had no previous diagnosis or symptoms of lymphoma. Management included computed tomography and/or magnetic resonance imaging scan and fine-needle aspiration (FNA). Results: Of the 251 patients, 10 were diagnosed with non- Hodgkin lymphoma (3.98%). Among them, 3 were identified as MALT subtype (30% of parotid lymphomas, 1.2% of all parotid neoplasms). FNA accuracy was 100% for the7 non-Hodgkin lymphomas, but only 33.3% (1 in 3 cases) regarding the MALT subtype. Interestingly, in these two patients, Warthin’s tumor was diagnosed by FNA. In one of the 3 cases of MALT lymphoma we came across a synchronous MALT lymphoma of the left parotid and high-grade non-Hodgkin lymphoma of the right breast (DLBCL). Conclusion: Our data suggest that MALT lymphoma of the parotid gland is rare and could be difficult to diagnose with FNA, probably due to similar underlying cytologic features to benign tumors.