A 14-month-old boy developed left eye strabismus following sustentacular systemic vinblastine, cyclophosphamide, and local radiotherapy for an alveolar RMS (
PAX3-FOXO1 positive) of the right buttock diagnosed elsewhere at the age of 5 months. Previous treatments included systemic polychemotherapy (carboplatin, doxorubicin, vincristine, ifosfamide, etoposide and actinomycin) (CWS-2009 protocol), five cycles given prior, and four after incomplete surgical resection of the tumor. Ophthalmic evaluation revealed bilateral rb, that was also present in the younger asymptomatic monozygotic fellow twin. Fundus examination of the 3-year older brother and the parents was normal. Both twins were referred to Lausanne for further treatment. Examination under anesthesia of the elder one revealed three partially regressed tumors in the right eye (OD) and two relapsing tumors in the left eye (OS) associated with diffuse subretinal seeding, consistent with International Intraocular Retinoblastoma Classification (IIRC) Group B in OD and group D in OS (Fig.
1). Intraocular tumor regression was achieved with one intra-arterial melphalan (3.7 mg) in OS and bilateral focal treatments (5 sessions of cryotherapy and/or thermotherapy given over 5 months). However, about a year following the diagnosis of rb, the child unfortunately developed refractory multifocal metastatic RMS involving both lower extremities (Fig.
2A), the lungs, and the brain confirmed on histopathology and immunostaining (Fig.
2B, C), and succumbed to his disease. The fellow twin had rb IIRC group B in OD and group D in OS treated with one cycle of systemic chemotherapy followed by three intra-arterial melphalan in OS together with bilateral focal treatments and remained tumor-free at 6 years follow-up.