Lacrimal sac lymphoma: A series of Japanese patients.

To present cases of primary lacrimal sac lymphoma in a Japanese population. In this retrospective case series, five cases (two males and three females; mean age: 49.8 years; age range: 38-62 years) were included. Clinical features, diagnostic findings, and treatment outcomes were collected and reviewed. Most patients presented with a swelling or mass in the medial canthal area. Only one patient presented with epiphora, while another patient also complained of pain which was due to inflammation. Imaging studies revealed a lacrimal sac mass with involvement of the nasolacrimal duct and variable involvement of the nasal cavity. Histopathological findings revealed three cases of diffuse large B-cell lymphoma, one case of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue, and one case of follicular lymphoma. Four cases were treated with a combination of chemotherapy and immunotherapy, with one case necessitating additional radiotherapy. One case was treated with immunotherapy alone. The mean follow-up was 23 (range: 3-50) months. Four cases showed complete remission, while the remaining patient is still ongoing treatment. Diffuse large B-cell lymphoma is the most common type of lacrimal sac lymphoma in this series. Lacrimal sac tumors should be ruled out in the presence of epiphora, dacryocystitis, or a mass in the medial canthus, even in the absence of pain or bleeding. Combined chemotherapy and immunotherapy is an effective treatment for these cases.