Table 2. Definitions of Histologic Features Evaluated in Muscular Biopsies.

Features	Definition	Cutoff value
Smooth muscle
Atrophy	Thin and small smooth muscle fibers	Presence or absence
Hypertrophy	Thick and large smooth muscle fibers	Presence or absence
Calcification	Purple amorphous deposition in the tissue	Presence or absence
Interstitial fibrosis	Increased collagen fiber	Presence or absence
Myenteric plexus
Ganglion cells	Neuron	Presence or absence
Ganglionitis	Lymphocytic infiltration into ganglion cell cytoplasm	Presence or absence
Neuritis	Inflammation within or immediately around myenteric nerves	Presence or absence
Inflammation
Intramuscular eosinophil	Eosinophilic infiltration in smooth muscle fibers	Presence or absence
Intramuscular lymphocytes	Lymphocytic infiltration in smooth muscle fibers	Presence or absence
Perivascular inflammation	Inflammatory cells in the perivascular spaces	Presence or absence
Intravascular margination of inflammatory cells	Inflammatory cells in the vascular spaces	Presence or absence