Pilomatrixoma in a patient with bilateral retinoblastoma.

A 3-year-old girl with a history of bilateral retinoblastoma presented with a new right lower periorbital mass that showed calcifications on ultrasound. She had previously undergone systemic and intra-arterial chemotherapy for retinoblastoma but had no evidence of active disease for at least 6 months previously. Her family and oncologists feared that this mass was an extraocular metastasis of her retinoblastoma. On excision, it was diagnosed as a pilomatrixoma, an uncommon benign neoplasm that originates from the matrix of the hair root. This is the first reported case of pilomatrixoma in a patient with retinoblastoma.