Retinoblastoma

Aka: Retinoblastoma

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II. Definitions

  1. Retinoblastoma
    1. Childhood intraocular tumor

III. Epidemiology

  1. Rare malignant tumor of Retina
    1. Represents 2% of Childhood Cancers (seventh most common childhood malignancy)
    2. Most common intraocular malignancy
  2. Incidence: 1 in 20,000 live births
  3. Average age of diagnosis: 12-18 months old
  4. Possible hereditary etiology

IV. Pathophysiology

  1. Retinal germ cell tumor (neuroblastic tumor)
  2. Tumor invades vitreous or grows beneath Retina
  3. Disease occurs when RB Protein gene inactivated
    1. Retinoblastoma (RB) Protein is tumor suppressor
      1. Coded on Chromosome 13, region 14
      2. Protein absent if both Alleles inactivated
    2. Mutation inherited in 40% of cases
      1. Spontaneous onset in 60%

V. Signs: Screen at every well child check in first 3 years

  1. Pupillary Light Reflex by direct ophthalmoscope
    1. White (Leukokoria) replaces Red Reflex (60% of cases)
  2. Strabismus
  3. Other findings
    1. Eye irritation (redness or tearing)
    2. Glaucoma
    3. Hyphema
    4. Corneal Opacification

VI. Imaging

  1. Ultrasound of orbits is preferred imaging modality
  2. Ultrasound demonstrates calcification in Retinoblastoma

VII. Differential Diagnosis

  1. See Leukokoria

VIII. Management

  1. Small tumors without vitreous seeding
    1. Laser photocoagulation
    2. Cryotherapy (esp. anterior tumors)
  2. Large tumors
    1. Radiation (Plaques or external beam)
    2. Enucleation (>50% intraocular volume or extension)
  3. Metastases
    1. Systemic Chemotherapy

IX. Associated Conditions

  1. Strabismus (25%)

X. Complications

  1. Blindness in one or both eyes
  2. Mortality
  3. Second malignancy before age 50 years
    1. Perform Genetic Testing
    2. Risk if 50% if Retinoblastoma from germline mutation
    3. Higher risk if Radiation Therapy (esp. age <1 year)
    4. Associated tumors
      1. Sarcoma
      2. Osteogenic Sarcoma
      3. Melanoma

XI. Prognosis

  1. Uniformly fatal without treatment
  2. Survival of primary tumor with treatment: 90%
  3. High risk of secondary tumor (Osteogenic Sarcoma)
  4. Survival increases if diagnosed before age 2 years

XII. Prevention: Screening

  1. General population of children under age 3
    1. Red Reflex Exam at delivery and each well child exam
  2. Family History of Retinoblastoma
    1. Genetic Counseling for parents prior to conception
      1. Consider Retinoblastoma gene testing
    2. Red Reflex
      1. Monthly for first year
      2. Every other month for ages 2-3 years

XIII. References

  1. Berson (1987) Ophthalmology Study Guide, AAO, p. 95-110
  2. Abramson (1998) J Pediatr 132:5.5-8 [PubMed]
  3. Essman (1992) Am Fam Physician 46(4):1243-52 [PubMed]
  4. Melamud (2006) Am Fam Physician 73:1039-44 [PubMed]
  5. Mills (1999) Am Fam Physician 60(3):907-16 [PubMed]
  6. Shields (1999) J Pediatr Ophthalmol Strabismus 36:8-18 [PubMed]
  7. Simon (2001) Am Fam Physician 64(4):623-8 [PubMed]

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