Primary diffuse large B-cell lymphoma of the lacrimal sac with involvement of maxillary sinus: a case report and review of literature.

Primary lacrimal sac lymphoma is a rare condition, often presenting with nasolacrimal duct obstruction. Herein, we present a unique case of diffuse large B-cell lymphoma (DLBCL) involving the lacrimal sac, maxillary sinus, and infraorbital nerve. Prompt diagnosis via biopsy is essential for timely treatment and the prevention of tumor progression. A 66-year-old female presented with intractable epiphora, infraorbital nerve hypesthesia, and medial canthal swelling. Imaging revealed a soft tissue mass in the right maxillary sinus extending into the right inferior orbit and nasal cavity. A biopsy confirmed DLBCL, prompting systemic chemotherapy. Residual disease prompted high-dose involved-site radiation, resulting in tumor regression. To our knowledge, this is the first case of primary DLBCL of the lacrimal sac with concurrent involvement of the maxillary sinus and infraorbital nerve. This case underscores the significance of lacrimal sac biopsy in refractory dacryocystitis or unilateral sinus disease and the effectiveness of multimodal treatment approaches in managing DLBCL.