Endoscopy (Figure 1) | Erythema, vesiculation, erosion, ulceration | Hyperemia, ulceration, inflammatory pseudopolyps | Normal to atrophic mucosa | Creamy mucosal patches, ulceration, mycotic abscesses | Mucosal and submucosal mass lesions |
Histopathology (Figure 2) | Viral cytopathic effects, inflammatory infiltrates, necrotizing vasculitis | Mucosal epithelial degeneration, loss of intestinal microvilli, cytologic atypia, epithelial fissures, inflammatory infiltrates, abundant foamy macrophages (MAI) | Mucosal atrophy, inflammatory infiltrates, eosinophilia (Isospora), histiocytosis in lamina propria (Leishmania) | Cell necrosis, pseudomembranes, hyphae penetrating intact mucosa and vasculature | KS: spindle cell neoplasms with irregular slit-like spaces; NHL: dense proliferation of uniform, small, round, cells |