Diagnostic clues in patients with clinical malabsorption and pathological small intestinal villous atrophy: Immune-mediated type and beyond

Table 4 Histopathological staging of immunoproliferative small intestinal disease

Stage	Small intestine involvement	Lymph nodal involvement (mesenteric, other abdominal and retroperitoneal, etc.)
Stage A (benign)	Infiltration of the lamina propria, predominantly by mature lymphocytes and plasma cells, accompanied by variable degrees of villous atrophy	Mature plasmocytic infiltration, with limited disruption of the lymph node architecture
Stage B (intermediate)	Infiltration extending beyond the mucosa, spreading into the submucosa, characterized by atypical lymphoplasmacytic cells and immunoblastic-like cells, often associated with total or subtotal villous atrophy	Atypical plasmocytic and immunoblastic infiltration, leading to total or subtotal architectural disruption of the lymph nodes
Stage C (malignant)	Proliferation of histiocytes (Hodgkin sarcoma) affecting all layers of the intestinal wall. Large masses are formed and transformed into malignant lymphoma	Sarcomatous proliferation, extensively disrupting the entire lymph node architecture

Histopathological staging of immunoproliferative small intestinal disease by Evangelista-Leite et al[104] and Galian et al[124].