Primary Lacrimal Sac Diffuse Large B-cell Lymphoma Treated With Local Radiotherapy Alone: A Case With No Relapse After 21 Years of Follow-Up.

Primary lacrimal sac lymphoma is rare and diagnosed as diffuse large B-cell lymphoma in a predominant histopathological type. Systemic chemotherapy would be the standard of care, but local radiotherapy may be a treatment option toward a localized lesion. The present patient is a 54-year-old otherwise healthy woman with a right lacrimal sac mass, which was proven by excisional biopsy to be diffuse large B-cell lymphoma. Since she did not have any other systemic lesions on gallium scintigraphy and neck-to-abdominal computed tomography scans, which were the standard procedure at that time, she underwent local radiotherapy at 40 Gy. Two years later, at the age of 56 years, she developed radiation retinopathy with macular edema in the right eye and had spotty laser photocoagulation in the nasal half of the fundus. At the age of 57 years, she developed radiation cataract and underwent cataract surgery with intraocular lens implantation in the right eye. At the age of 58 years, the macular edema in the right eye became worse and remained active, resulting in poor visual acuity of 0.1. She thus underwent 25-gauge vitrectomy in the right eye to peel off the adhering posterior vitreous surface, together with the internal limiting membrane, as the standard procedure at that time. The visual acuity in the right eye was elevated to 0.6. She maintained the visual acuity afterward and had no relapse of lymphoma in 21 years from the diagnosis of primary right lacrimal sac diffuse large B-cell lymphoma. Local radiotherapy would still be a treatment option for localized lymphoma lesions such as primary lacrimal sac lymphoma.