The most common secondary malignancy in a patient having retinoblastoma is

Ref Robbins 9/e p293 Retinoblastoma is the most common primary intraocular malignancy of children . involvement of both eyes with pineal gland gland is called as trilateral retinoblastoma The pinealoblastoma in association with retinoblastoma is a primary tumor In approximately 40% of cases, retinoblastoma occurs in individuals who inherit a germ line mutation of one RB alleles .This variant of retinoblastoma is inherited as an autosomal dominant trait and is associated with osteosarcoma . Osteosarcoma is therefore the commonest secondary malignancy associated with retinoblastoma