[Metachronous bilateral retinoblastoma: a case report].

The patient is a 2-year-old male. The family consulted the Department of Ophthalmology, Shanghai Ninth People's Hospital, after noticing a white reflection in the pupil area of the child's right eye for 6 days. Following a thorough ocular and systemic examination, the patient was diagnosed with retinoblastoma (Group E, cT2bN0M0) of the right eye. The right eye was enucleated and classified as pathological stage pT3cN0M0. Postoperatively, systemic intravenous chemotherapy with the VEC regimen was administered. Genetic testing revealed a germline mutation in the RB1 gene: c.874 (exon9) delT (p.Tyr292fsTer9), necessitating close monitoring of the socket during follow-up visits. Three months after the operation, fundus examination revealed yellow-white lesions in the left eye, and bilateral retinoblastoma was diagnosed (Group E in the right eye, Group C in the left eye). Based on the ICRB and pTNM stages, the patient underwent six rounds of systemic intravenous chemotherapy and three rounds of cryotherapy in the left eye. No recurrence was detected with a 4-year follow-up. The patient was initially diagnosed with unilateral retinoblastoma, but later developed the disease in the contralateral eye during treatment, which was a case of metachronous bilateral retinoblastoma.