COMMENT

    Diffusely infiltrating retinoblastoma accounts for approximately 1% to 2% of retinoblastoma cases[3]. This subgroup is considered atypical in that it proliferates diffusely within the retina, rather than growing exophytically or endophytically. As a result, it may produce a pseudoinflammatory process and mimic retinitis, vitritis, uveitis, or endophthalmitis[4ª²6]. Therefore, intraocular malignancy should be included in the differential diagnosis of intraocular inflammation in children. From a large series of 900 patients with retinoblastoma, only one case presented as endophthalmitis, without a wellª²defined tumor, before undergoing vitrectomy[6].

    In addition, calcification is rare and a mass is usually not present in diffusely infiltrating retinoblastoma. Therefore, CT and Bª²scan ultrasonography are of less diagnostic value. Since the lesion destroys the sensory retina, enucleation is the treatment of choice. Due to this tumor¬ðs unusual infiltrative growth pattern, systemic chemotherapy and orbital radiotherapy may be useful adjuvant agents to prevent metastasis.

    In this case, the child presented with older age and the clinical picture of endophthalmitis, absent calcifications or

    Figure 1  A: Bª²scan ultrasonography demonstrated vitreous organization, stranding, and posterior vitreous separation, without evidence of solid mass or calcification;B: Bª²scan ultrasonography one day after silicone oil removal with more opacification than seen in Figure 1A, there was interval development of vitreous opacification and discrete nodular areas of calcification; C: Computed tomography scan demonstrated calcification at the pars plana without a discrete retina mass

    Figure 2  A: Very densely aggregated small round cells are intermingled with poorly stained areas. These small round cells stained deeply. (Hematoxylinª²eosin, original magnification¡Á40)£»B: In kytoplasm, brown deposits are visualized supporting the diagnosis of retinoblastoma. (Synaptophysin stain, original magnification ¡Á40)

    identifiable mass. The index of suspicion for retinoblastoma was low and vitrectomy was performed. Fortunately, no adverse effects of vitrectomy were identified[7].

    In summary, diffusely infiltrating retinoblastoma may present later in life with atypical features such as vitreous inflammaª²tion. Before planning for vitrectomy, the possibility of underlying retinoblastoma should be excluded. The absence of pain, conjunctival hyperemia, synechiae, cataract and vitreous fibrosis, active infection or history of trauma should alert the clinician to suspect retinoblastoma rather than inflammation.

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  1 Abramson DH, Schefler AC. Update on retinoblastoma. Retina 2004(6);24:828ª²848

2 Shields CL, Shields JA, Shah P. Retinoblastoma in older childª²ren. Ophthalmology 1991;98(3):395ª²399

3 Bhatnagar R, Vine AK. Diffuse infiltrating retinoblastoma. Ophthalmology 1991;98(11):1657ª²1661

4 Materin MA, Shields CL, Shields JA, Eagle RC Jr. Diffuse infiltrating retinoblastoma simulating uveitis in a 7ª²yearª²old boy. Arch Ophthalmol 2000;118(3):442ª² 443

5 Shields JA, Shields CL, Eagle RC, Blair CJ. Spontaneous pseudohyª²popyon secondary to diffuse infiltrating retinoblastoma. Arch Ophthalmol 1988;106(9):1301ª²1302

6 Shields CL, Honavar S, Shields JA, Demirci H, Meadows AT. Vitrectomy in eyes with unsuspected retinoblastoma. Ophthalmology 2000;107(12):2250ª²2255

7 Moshfeghi DM, Wilson MW, Grizzard S ,Haik BG. Intraocular surgery after treatment of germline retinoblastoma. Arch Ophthalmol 2005;123(7):1008ª²1012

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