To report management of a series of patients with primary malignant lacrimal sac tumors and to compare these results to the previously published literature.A total of 27 patients with pathologically confirmed primary malignant lacrimal sac lesions were enrolled into this study. Pathological classifications, clinical characteristics, various treatment modalities and follow-up time, including tumor recurrence, were documented. The outcome measures included overall survival, progression-free survival, and median survival time.Among 27 eligible cases, 33.33% (9/27) of the tumor was non-Hodgkin B-cell lymphoma, and 33.33% (9/27) was squamous cell carcinoma; both were the most common tumor in this series, followed by adenocarcinoma 18.52% (5/27), then melanoma 7.41% (2/27). Treatment modalities included surgery, radiotherapy, and/or chemotherapy, the overall survival rate of 27 patients was 70.37%, with a median follow-up of 45 months (range: 7 mo-16 y), 8 patients had died from metastatic disease, but 13 patients remained without evidence of recurrent tumor. The 5-year overall survival and progression-free survival for all cases were 73.33% and 66.67%, respectively. The median survival time for 5 deceased patients with interstitial brachytherapy was 98 months, and 5-year survival rate was 60%.In this series, among primary malignant lacrimal sac tumors, the proportion of lymphoma had increased when compared with the previously published literature, and multidisciplinary therapy may lead to a good prognosis in the majority of patients with the tumors and patients may benefit more from interstitial brachytherapy than external beam radiotherapy.Copyright © 2022 by Mutaz B. Habal, MD.