A child with bilateral hereditary retinoblastoma is later found to have a midline intracranial tumor arising in the pineal gland, histologically identical to the retinal tumor. This combination is termed:

• A Metastatic retinoblastoma via the optic nerve
• B Quadrilateral retinoblastoma
• C Trilateral retinoblastoma ✓
• D Medulloepithelioma of the pineal region

Explanation

Trilateral retinoblastoma is the association of bilateral hereditary retinoblastoma with a pineoblastoma, reflecting the common neuroectodermal origin of retinal cells and pineocytes, both expressing the RB1-suppressed pathway. It occurs in a small percentage of germline RB1 mutation carriers and carries a poor prognosis. Spread through the optic nerve would produce orbital or CNS metastasis rather than a primary pineal neoplasm, and medulloepithelioma is a separate rare tumor not linked to RB1 mutations.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.