Primary lymphoma in the salivary glands: report of five cases and review of the literature.

The finding of a lymphoma in a major salivary gland could mean one of two things: either it is part of a disseminated process, or it is the first clinicopathologic evidence of lymphoma. In the latter instance, whether the disease originated in the glandular stroma itself or in a paraglandular lymph node and then invaded the stroma, the lymphoma is defined as primary, as long as there is no detectable disease outside the salivary gland. Five cases of primary salivary gland lymphomas are described. All had a complete clinical staging including chest x-ray, bilateral bone marrow biopsy, liver-spleen scan, bilateral pedal lymphangiography and/or abdominal CT scan. There was no evidence of lymphoma outside the gland in any of the patients described; hence, these can be labeled as primary lymphomas of the salivary gland. Review of the literature suggests that this presentation of the disease is extremely rare. Although 324 cases of salivary gland lymphomas have been described in the literature, only six may be considered primary by our criteria. The remaining patients were either not adequately staged or had documented evidence of disease elsewhere at the time of diagnosis. The diagnosis of primary salivary gland lymphoma should not be made unless complete staging is performed.