Retinoblastoma with Isolated Parotid Gland Metastasis: A Report of 2 Cases with Review of Literature.

Abstract

Retinoblastoma, the most common primary intraocular malignant neoplasm in young children, show frequent metastasis to lymph nodes, central nervous system and bones. However, retinoblastoma metastasizing to parotid gland is very rare. We here present 2 cases of isolated parotid gland metastasis in two children with unilateral retinoblastoma. Case 1 was a one-year-old child presenting with left globe lesion which was diagnosed as Retinoblastoma. Post chemotherapy, enucleation was done which on histopathology examination showed retinoblastoma with scleral invasion and anterior chamber seeding. On 3 month follow up, patient presented with left parotid swelling. He underwent Fine needle aspiration cytology (FNAC) and Core needle biopsy which confirmed retinoblastoma metastasizing to parotid following which superficial parotidectomy was done as it was a solitary hotspot on PET-CT followed by localized radiotherapy and chemotherapy. While case 2, a 6-year-old child presented with left parotid swelling with a history of undergoing enucleation 3 months earlier in an outside hospital; Enucleation slides were reviewed in addition to patient undergoing FNAC and Biopsy from parotid swelling, all of which were consistent with Retinoblastoma metastasizing to parotid; This patient was lost to follow up; Although rare with only a few case reports in literature, both the pathologist and the clinician should be aware of retinoblastoma metastasizing to parotid, which when diagnosed and treated promptly has overall better prognosis in the cases reported so far.