Clinico-radiologic characteristics of lacrimal sac area swellings misdiagnosed as dacryocystocele or mucocele

Purpose Several non-lacrimal lesions can present with lacrimal sac area swelling mimicking a dacryocystocele or mucocele with a possibility of misdiagnosis. This study investigates the clinic-radiologic characteristics of the mimicking conditions compared to true lacrimal sac distension. Design Retrospective, comparative, interventional case series Participants Patients referred by primary care ophthalmologists between January 2015 and October 2021 with a misdiagnosis of dacryocystocele or lacrimal sac mucocele (n = 39) and an age-matched group of proven true lacrimal sac swelling (TLS group, n = 44). Methods Data collected included demographics, presenting features, investigations, management, histopathology, and outcomes. Both groups were statistically compared for several clinical and radiological variables. Results Final diagnoses in the mimicking group were skin/subcutaneous swellings (14/39, 35.9%), vascular malformations (10/39, 25.6%), inferomedial anterior orbital cysts (7/39, 17.9%), sino-orbital masses (5/39, 12.8%). Female gender (<0.001), epiphora (p = 0.001), and discharge (p < 0.001) were significantly more frequent in the TLS group. The mimicking group was more likely to be associated with a longer swelling duration (p < 0.001), a swelling extending beyond the lacrimal sac area (p <0.001), orbital signs (p <0.001), and periorbital abnormality. Non-patent lacrimal irrigation (p < 0.001) was significantly more frequent in the TLS group. On imaging, all swellings in the mimicking group were separate from the lacrimal pathway and 94.9% (37/39) extended beyond the lacrimal sac fossa. Conclusion Various cutaneous, subcutaneous, vascular, inferomedial orbital cystic, and sinonasal pathologies can present with lacrimal sac area swelling and mimic a TLS. A high index of suspicion, a thorough clinical evaluation and proper imaging are essential to avoid a misdiagnosis.