Classification of Vitreous Seeds in Retinoblastoma

Abstract

Purpose To evaluate the patient, disease and tumor characteristics of the three morphologically distinct groups of vitreous seeds in retinoblastoma presenting for treatment with ophthalmic artery chemosurgery: dust (class 1), spheres (class 2) and clouds (class 3) in primary and recurrent vitreous seeds. Design Retrospective cohort study of patients treated for vitreous seeds at Memorial Sloan Kettering Cancer Center between May 2006 and March 2015. Participants 135 eyes with active vitreous seeds, presenting for either primary treatment with ophthalmic artery chemosurgery, or with recurrent vitreous disease. Methods Vitreous seeds were classified into three groups: dust, spheres and clouds. Indirect ophthalmoscopy, fundus photography, ultrasonography and ultrasonic biomicroscopy were used to locate and evaluate the extent of retinal and vitreous disease. Patient and disease characteristics (age, laterality of disease, treatment status) were compared between classification groups. A two-tailed Fisher's exact test and paired Student's t-test were used for statistical analysis. Main Outcome Measures Age of patient, laterality of disease, location of retinal disease, extent of vitreous disease and treatment status. Results Primary treated disease: Patients with eyes containing class 3 (cloud) vitreous seeds were significantly older compared to patients with class 1 or 2 (p<0.05) seeds: median age for class 1, 2 and 3 was 11, 15.5 and 32 mos, respectively. Eyes containing class 3 seeds were significantly more likely to occur in the equator-ora region of the fundus (p<0.0001), in a diffuse pattern (p<0.0001), and in patients with unilateral disease (p<0.05), compared to class 1 and 2 seeds. Recurrent disease: Recurrent vitreous seeds were significantly more common to class 2 (p<0.05), occurring in a diffuse pattern (p=0.01) and in patients with bilateral disease (p<0.001). Conclusion The three classes of vitreous seeds have distinct clinical characteristics associated with age of patient, laterality of disease, extent and location of tumor-producing seeds. Furthermore, recurrent vitreous seeds appear to have a unique clinical profile compared to seeds receiving primary treatment.

Integrated Treatment during the Intravitreal Melphalan Era: Concurrent Intravitreal Melphalan and Systemic Chemoreduction

“…Eyes were classified according to the International Intraocular Retinoblastoma Classification (IIRC) System outlined by Linn Murphree [17] and the seeding classification outlined by Munier [14] and Francis et al [7, 18]. …”

Vitreous Disease in Retinoblastoma

“…This classification system is useful as a clinical descriptor and allows for comparisons between eyes in the literature. (Table 1) Furthermore, as has recently been discovered, the classification system can be associated with distinct patient and tumor characteristics along with response to treatment(2,4). …”

“…One belief is that they originate from tumor cell displacement into the vitreous(3). They typically occur in children of the youngest age (median 11 months) compared to spheres and clouds(4). They can originate in all locations of the fundus and do not have preponderance between unilateral and bilateral disease(4).…”

“…They typically occur in children of the youngest age (median 11 months) compared to spheres and clouds(4). They can originate in all locations of the fundus and do not have preponderance between unilateral and bilateral disease(4). Characteristically, they are found in a localized distribution, typically overlying a retinal tumor(4).…”

“…Some posit that spheres are the result of clonal expansion of tumor cells that have translocated into the vitreous(3,5). They typically occur in children who are not as young as those with dust, and not as old as children with clouds(4). Spheres predominantly originate from the macula-equator region of the fundus and equally between children with unilateral and bilateral disease(4).…”