Classification of Tumors of Small Intestine

Tumors of small intestine may be classified, based on histology, into:

1.    Epithelial tumors:

a.    Adenoma
i.    Tubular
ii.    Villous
iii.    Tubulovillous

b.    Intraepithelial neoplasia (dysplasia) associated with chronic inflammatory diseases
i.    Low-grade glandular intraepithelial neoplasia
ii.    High-grade glandular intraepithelial neoplasia

c.    Carcinoma:
i.    Adenocarcinoma
ii.   Mucinous carcinoma
iii.  Signet-ring cell carcinoma
iv.   Small cell carcinoma
v.    Squamous cell carcinoma
vi.   Adenonsquamous carcinoma
vii.  Medullary carcinoma
viii. Undifferentiated carcinoma

d.    Carcinoid tumor (Well differentiated endocrine neoplasm)
i.    Gastrin cell tumour, functioning (gastrinoma) or nonfunctioning
ii.    Somatostatin cell tumour
iii.    EC (Enterochromafin) cell, serotonin-producing neoplasm
iv.    L-cell, glucagon like peptide and PP (Pancreatic  polypeptide)/PYY (Polypeptide YY)-producing tumour

e.    Mixed carcinoid-adenocarcinoma

f.    Gangliocytic paraganglioma

g.    Others

2.    Non-Epithelial tumors:

a.    Lipoma
b.    Leiomyoma
c.    Gastrointestinal stromal tumour
d.    Leiomyosarcoma
e.    Angiosarcoma
f.    Kaposi sarcoma
g.    Others

3.    Malignant Lymphomas:

a.    Immunoproliferative small intestinal disease (includes alpha-heavy chain disease)
b.    Western type B-cell lymphoma of MALT
c.    Mantle cell lymphoma
d.    Diffuse large B-cell lymphoma
e.    Burkitt’s lymphoma
f.    Burkitt like or atypical Burkitt’s lymphoma
g.    T-cell lymphoma

• Enteropathy associated
• Unspecified

h.    Others

4.    Secondary Tumors

5.    Polyps:

a.    Hyperplastic (metaplastic)
b.    Peutz-Jeghers
c.    Juvenile