Table 3.

Guidelines of histological evaluation system of place of implantation – tissue response

Histologic feature	Score
	0	1	2	3	4
Inflammatory cell type/response — Polymorphonuclear cells — Lymphocytes	0	Rare, 1 to 5/hpf a	Rare,5 to 10/hpf a	Moderate infiltrate	Marked infiltrate
Plasma cells
Macrophages/gitter cells
Multinucleated giant cells MGC)	0	Rare, 1 to 2/hpf	Rare, 3 to 5/hpf
Necrosis	0	Minimal	Mild	Moderate infiltrate	Marked
Neovascularization	0	Minimal capillary proliferation, focal, 1 to 3 buds	Groups of 4 to 7 capillaries with supporting fibroblastic structures	Broad band of capillaries with supporting fibroblastic structures	Extensive band of capillaries with supporting fibroblastic structures
Fibrosis	0	Narrow band	Moderately thick band	Thick band	Extensive band
Astrocytosis/fatty infiltration

^a hpf = high-powered (400x) field