A rare case of bilateral retinoblastoma metastasizing into the forearm

Abstract

<br>We present a case of an 8-year-old boy who had undergone chemotherapy with transpupillary thermotherapy for bilateral retinoblastoma (RB) at the age of 6 months. The patient had left forearm pain at the present visit. Bilateral ocular examination did not reveal any signs of RB reactivation. However, bone scan with technetium 99m-methyl diphosphonate (99mTc–MDP) and magnetic resonance imaging (MRI) showed the presence of metastasis in the proximal end of the ulnar bone, which was confirmed on bone marrow biopsy. Based on PCR study and molecular analysis, Ewing's sarcoma was ruled out and the patient was confirmed to have metastatic RB. Subsequently, he underwent chemotherapy along with wide excision of left proximal ulna + extracorporeal radiation therapy (ECRT) + plate reconstruction. At 15-month follow-up, the patient was stable with absence of recurrence of RB. This case highlights the need for long-term follow-up of patients with RB and the need for timely detection and management of metastasis.<br>