B-cell lymphoblastic lymphoma masquerading as primary dacryocystitis: A case report.

Primary B-cell lymphoblastic lymphoma (B-LBL) of the lacrimal drainage system is exceptionally rare and diagnostically challenging. A 45-year-old man presented with left eyelid swelling, epiphora, medial canthal erythema, and a palpable mass in the lacrimal sac area. Imaging revealed an invasive mass with bone erosion and focal hypermetabolism (SUVmax 5.0). Although the initial clinical impression favored a chronic inflammatory process, the aggressive radiographic features raised suspicion of malignancy, prompting complete surgical resection of the involved lacrimal drainage system. The diagnosis of B-LBL was subsequently confirmed by histopathological examination and lymphocyte gene rearrangement studies. This case highlights a unique presentation of B-LBL in the lacrimal drainage system and demonstrates that B-LBL can mimic inflammatory conditions such as dacryocystitis. It underscores the importance of considering this malignancy in the differential diagnosis of atypical lacrimal masses.