Korean J Ophthalmol Vol.23, No.2, 2009 Fig. 4. Histological examination reveals a fungiform mass with projecting finger-like proliferation of the epithelium. The tumor has an exophytic growth pattern with branching fibrovascular stalks covered by an epithelial layer (Hematoxylin-eosin stain, ×40). Fig. 5. Transitional- type epithelial lining containing goblet cells (thick arrow). Occasionally, a single layer of columnar ciliated respiratory epithelial cells (thin arrow) is seen to line the surface of the hyperplastic transitional cells (Hematoxylin-eosin stain, ×200). tional cell papilloma. The epithelial lining was a transitional type and contained goblet cells. Occasionally, a single layer of columnar ciliated respiratory epithelial cells lined the surface of the hyperplastic transitional cells (Fig. 5). The papilloma had a partial severe dysplasia (Fig. 6). Pathologic examination confirmed the diagnosis of an exophytic Sch- neiderian papilloma with moderate to severe dysplasia. D iscussio n The nasolacrimal drainage system shares its epithelial origin with that of the sinonasal tract. The mucosal epithelium that lines the nasal cavity, paranasal sinuses, and lacrimal apparatus is unique in its embryogenesis, in that it is ectodermal 102 Fig. 6. A partial severe dysplasia in the papilloma (Hematoxylin- eosin stain ×600). in origin.1,2 A common synonym for this ectodermally derived mucosa and papilloma is the “Schneiderian mucosa” or “ Sch- neiderian papilloma”.4 The Schneiderian papilloma is an uncommon neoplasm. The lateral nasal wall is the most common site of origin.2 The lacrimal system is one of the most unusual primary locations,3 having been reported in Korea in only two cases reported.5,6 This case is a recurrent Schneiderian papilloma of the lacrimal sac that eventually invaded the nasal cavity through the nasolacrimal duct after mass excision of the lacrimal sac tumor. There is no prior report of recurrence and invasion of the nasolacrimal duct by an exophytic papilloma originating in the lacrimal sac. Valenzuela et al.7 reported the clinical presentation of lacrimal drainage apparatus tumors in 37 patients. Symptoms included epiphora, a palpable mass, dacryocysitis, discharge, a visible lesion, bloody discharge or tears, epistaxis, and non- axial globe displacement. This patient had chronic epiphora and a small palpable mass at the nasal canthal area. Irrigation of the lacrimal system revealed bloody discharge. Bloodstained discharge from the puncta should always be regarded as a significant finding whether spontaneous, secondary to pressure on the sac, or after irrigation.8 When found, surgical inter- vention is usually recommended, because it is suggestive of a lacrimal sac tumor. Radiographic examination of all masses that develop at the medial canthus is essential. Dacryocystography allows the identification of space-occupying tumors in the lacrimal sac. A characteristic dacryocystogram, as described by Veirs,9 shows a distended sac shadow, uneven or mottled density of the contrast media, and patency with residual media present 30 minutes after injection. Orbit and sinus CT scan, and MRI provide the most useful information about the extent of tumors and their relationship with surrounding bony structures and soft tissues.10 In this case, dacryocystography showed uneven contrast media at the right lacrimal sac, and evidence of a soft tissue mass. MRI of the orbit revealed a hetero-