LAUSR

To the Editor: In 2018, Curragh et al. presented a 58-year-old female who underwent neoadjuvant radiotherapy and nasolacrimal duct excision via prelacrimal approach for a right lacrimal sac squamous cell carcinoma (SCC) in-situ. The excision confirmed clear margins and tested positive for human papillomavirus (HPV). We provide follow-up information of her subsequent diagnosis with contralateral left lacrimal sac SCC and discuss various issues related to her management. The patient had remained clinically disease-free since 2017. However, she presented in late 2020 with a fourmonth history of a rapidly growing, fixed, firm nodule overlying her left medial canthus. Magnetic resonance imaging (MRI) indicated a contrast-enhancing, left lacrimal sac mass (Figure 1) and biopsy confirmed noninvasive SCC in-situ. Bilateral lacrimal sac tumors are rarely reported, with postulated mechanisms including infectious aetiologies (e.g. HPV) as seen in our patient, independent de novo origins, SCC seeding from eye rubbing, contralateral metastases, or malignant transformation of benign lesions. Treatment usually involves surgical resection, and if necessary, a reduced dose of adjuvant radiotherapy and/ or chemotherapy. More recently, high-dose neoadjuvant radiotherapy, as previously used for her right-sided tumor (Figure 1), has been shown to facilitate resection and reconstruction for improved tumor clearance, cosmesis and functional outcome. The risk of radiation-induced side-effects, dependent on total and fractional dose, can be reduced with careful planning, conservative dosage, and globe-sparing techniques. On balance, and after extensive multidisciplinary discussion, the patient accepted our recommendation to pursue neoadjuvant radiotherapy (46.8 gy over 26 fractions) and surgery for her latest tumour.