Salivary gland lymphoproliferative disorders: a Canadian tertiary center experience.

Salivary gland lymphoproliferative disorders (SGLD) are very rare tumors and clinicopathological data is sparse. In a Canadian series of 30 cases, extracted from the surgical pathology files of The Ottawa Hospital between 1990 and 2010, a clinical, histopathological, and immunophenotypic analysis was conducted. Tumors were staged using the Ann Arbor staging and classified using the World Health Organization 2008 classification. There were 15 salivary gland (SG) primary lymphomas with localized disease, predominantly mucosa associated lymphoid tissue type marginal zone lymphoma (MALT-L), but with a significant incidence of low grade follicular lymphoma (FL) and diffuse large B cell phenotype as well. There were 7 systemic SG lymphomas and 5 patients were diagnosed with lymphoproliferative disorders originating from intra-parotid lymph nodes. Finally, the remaining 3 cases represented reactive sialadenitis. A literature review was conducted and our primary lymphoma group was compared to those from other countries. SGLDs are predominantly B cell lymphomas that develop in older adults. Primary tumors, which have MALT-L and low grade FL characteristics, have a favorable survival, however MALT-L have a high rate of relapse. A minority of SG lesions are excised secondary to lymphomas that definitely arose from intra-parotid lymph nodes.