1. Mee Kum Kim 1,2, Kyoung Min Lee 1,2, Young Eun Lee 1,2, Won Ryang Wee 1,2 1 Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea Seoul National University Hospital, Seoul, Korea The authors have no financial interest in the subject matter of this poster 2 Laboratory of corneal regenerative medicine and ocular immunology, Seoul Artificial Eye Center, Seoul National University Hospital Clinical Research Institute, Seoul, Korea

4. Visual acuity (0.5 / 1.0) Ant. Seg - L) 2 conjunctival masses - R) PSC, L) PCL in situ Fundus - B) normal posterior pole Orbit CT - No other mass lesion

5. Assessment - L) conjunctival masses R/O L) xanthogranuloma R/O L) atypical lymphoma L) Excisional biopsy and cryotherapy cryotherapy - 4.5 mm(H) x 3.0mm (V) - 2.0mm (H) x 1.0mm (V) ※ Adhesion between the sclera and masses POD 2 month Injection had persisted 3 months after operation

6. x 100 X 400 x 200 Tuoton cell (multi-nucleated giant cell) Dense infiltration of histiocytes

7. Histiocyte marker CD 68 (brown) Nucleus (blue) x 100 x 200 X 400

8. x100X200 x400 Langerhans cell marker CD 1a(brown) - absent Nucleus (blue)

9. x 100 x 200 x 400 Langerhans cell marker S-100 (brown) Nucleus (blue)

10. CD 3 stain CD 3 stain T-cell marker CD 20 stain CD 20 stain B-cell marker x 100x200x 400 x 100x 200x 400

11. H&E stain - Histiocytes nfiltration - Tuoton cells Histiocytosis R/O Xanthogranuloma R/O Langerhans cell histiocytosis Positive : CD 68: Histiocytes Partial positive : CD3: T-cell : CD20: B-cell Negative S-100, CD1a : : Langerhans cells Xanthogranuloma

12. Unique features of this case - Adult onset juvenile xanthogranuloma - Pure conjunctival mass - Infiltrative nature Conjunctiva linfiltrative mass in adult - Juvenile xanthogranuloma should be considered as differential diagnosis - Immunophenotyping is helpful.