Metastasis of retinoblastoma to the parotid gland: Diagnosis by fine needle aspiration cytology

Retinoblastoma is the most common malignant tumor of the eye in childhood, with an incidence of about 1:15,000 live births, depending on the population studied. It usually presents with leukocoria, but it may manifest as strabismus, vitreous hemorrhage, hyphema, glaucoma, proptosis, or red eye.(1) Common sites of metastasis, either at initial presentation or at recurrence, include the bones, bone marrow, and meninges. However, metastasis to the salivary glands is very rare, with only 4 previously reported cases, all to the parotid gland.(2-4) Characteristic histopathologic features of retinoblastoma are of a "small cell" tumor exhibiting Flexner-Wintersteiner rosettes, with varying degrees of suppressor gene RB1, either as a familial trait or as a de novo mutation.(1) The management of retinoblastoma includes enucleation of eyes with little hope of vision, irradiation, brachytherapy, cryotherapy, photocoagulation, and chemotherapy (for eyes in which there is the chance to salvage some vision).