Co-occurrence of retinoblastoma and oculocutaneous albinism in a Mexican patient: a case report

Introduction Retinoblastoma (RB) and oculocutaneous albinism (OCA) are genetically independent disorders whose coexistence is exceptionally rare, with an estimated theoretical frequency of 1 in 800 million births.Methods We report a 5-month-old Hispanic male with OCA who developed unilateral multifocal RB. Next-generation sequencing identified a de novo heterozygous pathogenic RB1 nonsense variant (c.1411C > T, p. Gln471*) and homozygous pathogenic OCA2 missense variant (c.2228C > T, p. Pro743Leu).Results The profound retinal hypopigmentation characteristic of OCA precluded standard pigment-dependent focal therapies. Following systematic vincristine, carboplatin and etoposide chemotherapy, pigment-independent cryotherapy was successfully employed to target the tumor via freeze-thaw injury. Complete tumor regression was achieved, with no recurrence over 7 years of follow-up.Results Discussion: This case demonstrates that RB can be successfully treated with cryotherapy and chemotherapy in children with severe fundus hypopigmentation. It highlights the clinically-relevant role of molecular genetic testing in establishing dual diagnoses and underscores the necessity of lifelong multidisciplinary surveillance due to the cumulative oncogenic risks associated with both germline conditions.