Abstract: Objective: To summarize the CT manifestations of malignant lymphoma in parotid region and analyze the CT imaging characteristics of different pathological types. Methods: Twenty cases of parotid malignant lymphoma in our hospital were collected, and the clinical characteristics, CT manifestations, histopathology, and immunohistochemical results were reviewed. CT manifestations included the number, size, boundary, density, and regional lymph node involvement of lesions. Pathological classification was performed combining histopathological observations and immunohistochemistry analysis, and tumor cell proliferation analysis was performed by immunohistochemistry analysis of Ki-67. Results: All 20 cases of malignant lymphoma were non-Hodgkin's lymphoma (NHL), 9 cases were mucosal associated lymphoid tissue lymphoma (MALT), 8 cases were diffuse large B cell lymphoma (DLBCL), 2 cases were follicular lymphoma (FL), 1 case was angioimmunoblastic T-cell lymphoma (AITL). Of 9 MALTs, 7 cases manifested unclear boundaries, 6 cases were plasticized along the parotid contour, and 8 cases manifested uneven density. Of 8 DLBCLs, 7 cases manifested clear boundary, 4 were single nodules and 4 were multiple nodules, 4 presented uniform density, and 4 presented uneven density. 14 of the 20 cases had lymph node involvement. Ki-67(+) was distributed in 20%~90%, and 4 DLBCLs had Ki-67(+) higher than 50%. Conclusion: Most of parotid malignant lymphoma is MALT or DLBCL, both of them have some radiographic manifestations in spiral CT images.

Key words: parotid malignant lymphoma, diffuse large B cell lymphoma, mucosal associated lymphoid tissue lymphoma, spiral computed tomography