The Final Diagnosis: Retinoblastoma or Pseudoretinoblastoma.

Purpose: To review the authors' experience in the diagnosis of retinoblastoma and to explore the frequency of intraocular conditions that mimic this malignancy according to patient age at presentation.

Methods: This was a retrospective observational study including 549 patients (769 eyes) who were referred for confirmation and/or management of retinoblastoma between October 1998 and June 2019 at a single tertiary center. A detailed ocular examination was done by the same ocular oncologist under general anesthesia for every patient.

Results: Of 549 patients referred for diagnostic confirmation or management of retinoblastoma, 393 (71.6%) patients were found to have retinoblastoma and 156 (28.4%) patients received the diagnosis of pseudoretinoblastoma. The mean patient age at presentation was 52.1 months, ranging from 1 to 276 months. The most common diagnoses among patients with pseudoretinoblastoma younger than 1 year were persistent fetal vasculature (PFV) (n = 19; 28.8%), Coats disease (n = 7; 10.6%), chorioretinal coloboma (n = 4; 6.1%), retinal dysplasia (n = 4; 6.1%), and retinal detachment (n = 4; 6.1%). In patients with pseudoretinoblastoma who were 1 to 5 years old, the most common diagnoses were Coats disease (n = 10; 25.6%), PFV (n = 7; 17.9%), and optic disc hypoplasia (n = 3; 7.7%). Patients older than 5 years were most likely to have Coats disease (n = 8; 15.7%), optic disc drusen (n = 5; 9.8%), retinopathy of prematurity (n = 4; 7.8%), and combined hamartoma (n = 4; 7.8%).

Conclusions: This study shows that 28.4% of patients referred for suspicion or management of retinoblastoma were classified as having pseudoretinoblastoma. The most common conditions causing diagnostic confusion with retinoblastoma included PFV and Coats disease, similar to previous publications from both high-and low-income countries. .