Retinoblastoma showing the pathological finding of Homer-Wright rosettes (without a lumen) is classified as:

• A Flexner-Wintersteiner rosettes indicating good photoreceptor differentiation
• B A feature of poor differentiation (undifferentiated retinoblastoma)
• C Fleurettes indicating full photoreceptor differentiation
• D Homer-Wright rosettes indicating neuroblastic differentiation ✓

Explanation

Retinoblastoma histology shows three types of rosettes: Flexner-Wintersteiner rosettes (ring of cells around a central lumen representing photoreceptor differentiation, most specific for retinoblastoma); Homer-Wright rosettes (cells around fibrillary processes without a true lumen, seen in neuroblastic tumours including retinoblastoma and medulloblastoma, indicating neuroblastic but not specifically photoreceptor differentiation); and fleurettes (bouquet-like structures with full photoreceptor differentiation, seen in retinocytoma/retinoma). Homer-Wright rosettes are not specific to retinoblastoma but indicate neuroblastic differentiation.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.