Lacrimal Sac Mucoepidermoid Carcinoma with Metastases to the Cavernous Sinus Following Dacryocystorhinostomy Treated with Stereotactic Radiotherapy

PURPOSE: We report a very good outcome in a 44-year-old woman in whom cancer was missed as the cause of nasolacrimal duct obstruction and dacryocystitis and which was deemed inoperable after spreading to the cavernous sinus. CASE REPORT: The patient was referred to our unit 12 months following uneventful right dacryocystorhinostomy for nasolacrimal duct obstruction. This had been complicated by the formation of a significant canthal swelling 6 months later, which had been excised at that time. The symptom of nasolacrimal duct obstruction and scar recurrence prompted the referral to our unit. Examination and biopsy confirmed a malignancy. Despite extensive surgery, including concurrent radical neck dissection and parotidectomy, within 6 months, her mucoepidermoid carcinoma was found to have spread to the cavernous sinus, restricting blood flow from the carotid and causing an abducens nerve palsy. Though deemed inoperable at first, Gamma Knife stereotactic radiosurgery was sought as treatment for her disease, resulting in a good outcome 4 years after surgery. CONCLUSION: Experience from this case suggests the importance of considering malignancy as a cause in young patients when presenting with nasolacrimal duct obstruction. In such cases, and perhaps for all patients, biopsy specimens should be submitted as many tumours are found incidentally at the time of dacryocystorhinostomy. Whilst the external approach to dacryocystorhinostomy may identify abnormal anatomy intraoperatively, prompting biopsy, this is less likely with an endonasal approach where osteotomy precedes sac visualisation. The endonasal approach may therefore be less appropriate in such cases where malignancy is suspected as osteotomy may aid in the spread.