NK-Cell Lymphoma Involving the Parotid Gland: A Rare Case

Malignancies arising from putative natural killer (NK) cells are recently recognized distinct lymphoma subtype. Clinically, these lymphomas present most commonly as destructive lesions in the nasal cavity and other midline facial structures. Lymphomas of putative NK cells occur primarily in nonnasal areas including skin, gastrointestinal tract, salivary gland, testis and muscle. The molecular mechanisms leading to malignant transformation of NK cells remain undefined but one of the pathogenetic association is EBV infection. Lymphoma infiltration is seen with prominent necrosis and vascular destruction. Although the clinicopathological features of NK cell lymphomas are well defined, the optimal therapy and treatment outcomes are unclear. Unfortunately, the treatment of NK cell lymphoma has been unsatisfactory. Conventional chemotheraphy treatment regimens have resulted in very poor complete remission rates and long-term survival. Here we presented an unusual case of NK cell lymphoma involving the parotid gland.