Etiology, Genetics, Pathogenesis, Pathology, Sequelae, and Complications of Retinoblastoma

Etiology of Retinoblastoma

Retinoblastoma is a rare malignant tumor of the retina primarily affecting children. The etiology involves genetic mutations and environmental factors that contribute to tumor development.

Genetic Mutations

The most critical genetic mutation linked to retinoblastoma occurs in the RB1 gene located on chromosome 13. This gene is responsible for tumor suppression. Inactivation of both alleles leads to uncontrolled cell proliferation and malignancy.

• Hereditary Retinoblastoma: Occurs due to a germline mutation in RB1, often bilateral.
• Sporadic Retinoblastoma: Results from somatic mutations, usually unilateral.

Environmental Factors

Although genetic mutations play a primary role, environmental factors such as radiation exposure, parental age, and certain infections may influence tumor development.

Pathogenesis of Retinoblastoma

Retinoblastoma originates in the immature retinal cells due to loss of function in the RB1 gene. The disrupted tumor suppression mechanisms result in uncontrolled cell proliferation, leading to tumor formation.

Pathology of Retinoblastoma

Histologically, retinoblastoma presents as small, round, blue-cell tumors with characteristic Flexner-Wintersteiner rosettes. The tumor can spread locally into the optic nerve or metastasize via hematogenous or lymphatic routes.

Sequelae and Complications

Untreated or advanced retinoblastoma can lead to several complications:

• Visual Impairment or Blindness
• Ocular Atrophy
• Orbital Extension
• Metastasis to the Brain and Bone Marrow

Early detection and intervention are crucial to improving prognosis and preserving vision.