JH Jang, et al. A SCHNEIDERIAN PAPILLOMA OF THE LACRIMAL SAC geneous enhancing mass, approximately 18×9 mm, in the right lacrimal sac and upper nasolacrimal duct. The mass lesion extended anteriorly to the facial soft tissue, but no bony destruction was observed. Histological examination of excised tissue is essential to confirm diagnosis. As presented by Ryan and Font,3 lacrimal papillomas can be subdivided by growth pattern into exophytic, inverted, or mixed in architecture. Another classification, reported by Ashton et al.11 defines transitional cell papillomas, intermediate types, and transitional cell carcinomas. In this case, the Schneiderian papilloma had an exophytic growth pattern. The lesion was a transitional cell papilloma, with stratified columnar epithelium and scattered goblet cells, with partial severe dysplasia. The possibility of malignant change must always be con- sidered. In the cases studied by Ryan and Font,3 7 out of the 12 inverted or mixed-type papillomas presented either as carcinomatous lesions or progressed to invasive carcinoma; none of six exophytic papillomas developed into carcinomas, however. This patient had an exophytic Schneiderian papilloma with moderate to severe dysplasia, which may precede the development of a malignancy. An exophytic type papilloma does notrule out malignant potential. Recurrence is a major clinical problem in the treatment of Schneiderian papillomas. Hyams,12 reported on papillomas of the sinonasal tract, and found a recurrence rate of 40-60% for all papillomas, regardless of type. All recurrences occurred at essentially the same anatomical site as the previous surgically removed tumor. We concluded that this case was a recurrent Schneiderian papilloma caused by incomplete removal of the lacrimal sac papilloma. The therapeutic approach to this type of tumor has to be planned carefully. Sham et al.13 recommended that guidelines for the surgical treatment of Schneiderian papillomas include the following: 1) the papilloma should not be managed as a completely benign lesion; 2) the best opportunity for successful control of the papilloma is the first surgical procedure and; 3) the more open the approach, the better the accessibility, the more complete the resection, and the lower the chance of recurrence. In conclusion, a Schneiderian papilloma of the lacrimal sac is a locally aggressive benign epithelial tumor with malig- nant potential. Incomplete tumor excision causes higher recurrence rates with spreading into the other nasolacrimal system. Therefore, a Schneiderian papilloma of the lacrimal sac must be accurately diagnosed by histopathological exami- nation, and completely removed by surgical excision. References 1. Batsakis JG. Suarez P. Schneiderian papillomas and carcinomas: A review. Adv Anat Pathol 2001;8:53-64. 2. Batsakis JG. Nasal (Schneiderian) papillomas. Ann Otol Rhinol Laryngol 1981;90:190-1. 3. Ryan SJ, Font RL. Primary epithelial neoplasms of the lacrimal sac. Am J Ophthalmol 1973;76:73-88. 4. Ridolfi RL, Lieberman PH, Erlandson RA, Moore OS. Schnei- derian papillomas: a clinicopathologic study of 30 cases. Am J Surg Pathol 1977;1:43-53. 5. Choi KH, Yoon BJ. A case of squamous cell papilloma of the lower canaliculus. J Korean Ophthalmol Soc 1982;23:179-81. 6. Lee JB, Huh K, Lee TS. A case of squamous cell papilloma of the lacrimal sac. J Korean Ophthalmol Soc 1991;32:89-94. 7. Valenzuela AA, McNab AA, Selva D, et al. Clinical features and management of tumor affecting the lacrimal drainage apparatus. Ophthal Plast Reconstr Surg 2006;22:96-101. 8. Flanagan JC, Stokes DP. Lacrimal sac tumors. Ophthalmology 1978;85:1282-7. 9. Veirs ER. The lacrimal system First International Symposium. St. Louis: C.V. Mosby Co, 1971:81. 10. Parmar DN, Rose GE. Management of lacrimal sac tumours. Eye 2003;17:599-606. 11. Ashton N, Choyce DP, Fison LG. Carcinoma of the lacrimal sac. Br J Ophthalmol 1951;35:366-76. 12. Hyams VJ. Papillomas of the nasal cavity and paranasal sinuses. A clinicopathological study of 315 cases. Ann Otol Rhinol Laryngol 1971;80:192-206. 13. Shan CL, Woo JK, vanHasselt CA. Endoscopic resection of inverted papilloma of nose and paranasal sinuses. J Laryngol Otol 1998;112:758-64. 103