Retinoblastoma

Retinoblastoma is a malignant tumour the of the eye.

Retinoblastoma
Diagnosis in short
Retinoblastoma. (WC)
LM	small round cell tumour, Flexner-Wintersteiner rosettes, +/-Homer-Wright rosettes, mitoses (common), +/-necrosis, +/-calcifications
LM DDx	retinocytoma, other small round cell tumours
Gross	white, solid, friable
Site	eye
Prevalence	rare

General

• Rare.
• Malignant.
• May be familial.

Gross

• White, solid.
• Patterns:
  • Endophytic - grow into the vitreous cavity.
  • Exophytic - grow toward choroid.
  • Mixed - components of endophytic and exophytic.

Note:

• Tumour is extremely friable.

Image

• Retinoblastoma (radiopaedia.org/AFIP).

Microscopic

Features:

• Small round cell tumour:
  • Scant cytoplasm.
• Flexner-Wintersteiner rosette - key feature.
  • Rosette with empty centre (donut hole).
• +/-Homer-Wright rosette.
  • Circular rosette with neuropil at the centre.
• Mitoses - common.
• +/-Necrosis.
• +/-Calcification.

DDx:

• Retinocytoma (retinoma) - benign counterpart of retinoblastoma.

Notes:

• DDx of Flexner-Wintersteiner rosette includes:
  • Pineoblastoma.
  • Medulloepithelioma.

Images

• 

  Retinoblastoma. (WC)

www

• Retinoblastoma (ouhsc.edu).
• Retinoblastoma (pathpedia.com).

See also

• Eye.
• Small round cell tumours.