A Rare Metastatic Squamous Cell Carcinoma of the Lacrimal Sac Originating from Nasopharyngeal Carcinoma: A Case Report.

Background and Clinical Significance: Metastatic carcinoma of the lacrimal sac originating from primary nasopharyngeal carcinoma (NPC) is a rare entity, usually presenting with chronic, unilateral epiphora. Case Presentation: A 55-year-old male patient presented with symptoms of chronic persistent dacryocystitis of the left eye for a year. His history revealed a non-keratinizing NPC diagnosed 5 years earlier, which was treated with combined radiotherapy (RT) and chemotherapy (CMT). Following CT and MRI scans, a mass was identified at the left lacrimal sac suggestive of a neoplasm in that region. The patient underwent endoscopic dacryocystorhinostomy (DCR), with tissue samples taken for biopsy. The histopathological diagnosis revealed a metastatic carcinoma of the lacrimal sac originating from the nasopharynx. The postoperative course was uneventful. However, a follow-up positron emission tomography-computed tomography (PET-CT) scan showed a hypermetabolic lesion in the left orbital cavity, infiltration of the lacrimal sac, hypermetabolic lateral cervical lymph nodes (IIA-IIB), and a hypermetabolic parotid lymph node. The patient is currently receiving combined CMT and immunotherapy (IMT) and is scheduled to receive RT thereafter. Conclusions: The non-specific symptomatology of the disease might be a reason for delayed diagnosis. Early recognition requires a high index of suspicion, while therapy mainly focuses on RT, CMT, IMT, and rarely on surgical approaches. A multidisciplinary approach and coordination are indispensable for the best possible treatment outcome.