Table 1.

Biopsy approach techniques.

Surgical Approach	Biopsy Type	Gauge Needle	Main Advantages	Main Disadvantages	Sample Use
Transscleral	Excisional biopsy	NA	Large sample	Risk of seeding when performed before irradiation Surgically demanding Ocular complications	histopathology and genetics
	Fine-Needle Aspiration biopsy	25 G–30 G	Cheap; Simple technique	Relatively small amount of tissue Not indicated in small tumors Not indicated in post-equatorial tumors	cytopathology and genetics
Transvitreal	Fine-Needle Aspiration biopsy	25 G–27 G	Cheap	Relatively small amount of tissue Risk of retinal complication and vitreous hemorrhages	cytopathology and genetics
	Vitrectomy-based biopsy	25 G–27 G	Relatively large amount of tissue	Expensive Risk of retinal complication and vitreous hemorrhages Requires vitrectomy expertise	cytopathology and genetics
	Essen forceps biopsy	23 G	Relatively large amount of tissue	Risk of seeding? Risk of retinal complication and vitreous hemorrhages	cytopathology and genetics
	Incisional biopsy	NA	Large sample	High risk of retinal complication and vitreous hemorrhages	histopathology and genetics
	Vitrectomy-based endoresection	25 G–27 G	Large sample	High risk of retinal complication and vitreous hemorrhages Surgically demanding Risk of seeding if performed before irradiation	histopathology and genetics

NA = Not applicable; G = Gauge; Table modified from Bagger MM et al. Acta Ophthalmol. 2018, 96 Suppl A112, 1–28.