Abstract
Purpose: :
To evaluate the incidence and clinical, histopathologic, and genetic features of retinoblastoma (RB) in children over age 5 years.
Methods: :
Retrospective chart review of 130 consecutive patients with RB who presented to the Retina Service of the Massachusetts Eye and Ear Infirmary.
Results: :
Seven patients (5.3%) had initial diagnosis after 5 years of age (range 6 to 11 years, mean 8 years). There were 2 boys and 3 girls with unilateral active tumors (3.8% of all cases) and 2 children with inactive tumors (retinoma). Genetic testing for RB1 mutations was performed in four cases. Family history was negative in all cases. Four presented with unilateral decrease in vision. Three were referred with diagnoses of Coats disease with total exudative retinal detachment (RD), vascular dilatation and telangiectasia but on further examination had white plaques, subretinal tumor, and vessels going in and out of the tumor. Two cases had extensive, large vitreous spheres. Only two eyes had calcification on imaging (CT and US). One patient was referred with intractable uveitis with hypopyon, white iris nodules, vitreous cells, and a negative laboratory work-up. Neither examination nor imaging revealed a retinal mass, but a vitreous biopsy was positive for RB. All five patients underwent enucleation. The case that underwent vitreous biopsy received systemic chemotherapy and orbital proton radiotherapy (PRT). Histologic examination revealed retinal infiltration (diffuse infiltrative pattern) in all five cases. Discreet tumors were also present in all Coats-like eyes and one uveitis-like eye. Extrascleral extension was found in a single case (11 year old), and the patient was treated with chemotherapy and PRT. One case had a peripheral retinoma next to the RB. RB1 analysis found a homozygous non-sense mutation in codon 251 of exon 8 in the tumor of one patient. Mutation search is still pending in the other four cases. No recurrence was seen in follow-up of 16 to 66 months.
Conclusions: :
The presentation of RB in older children can mimic Coats disease and uveitis creating the potential for inaccurate or delayed diagnosis. Retinal infiltration and lower malignant potential appear to be common features of these tumors. Further genetic analysis may reveal whether this subset of RB is genetically distinct from the tumors found in younger children.
Keywords: retinoblastoma • tumors • pathology: human