Internal Medicine

0521779407-19 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:21

Small Bowel Tumors 1357

■Malignant neoplasms:

➣Adenocarcinoma

accounts for 25–50% of small bowel malignancies

incidence decreases from duodenum to jejunum

60% periampullary

Crohn’s disease, predominantly involves ileum

tendency to metastasize early to regional lymph nodes

■Carcinoid tumors

➣see chapter on carcinoid tumor

■Lymphoma

➣small bowel often involved (most common extranodal site)

➣mostly non-Hodgkin’s lymphomas

➣all types, including B-cell, large cell, immunoblastic, T-cell, inter-

mediate or high grade

➣most common in the ileum

➣typical symptoms are fatigue, weight loss, pain

■Sarcomas

➣rare (1% of small bowel malignancies)

➣most common in jejunum, ileum, and Meckel’s diverticula most

common type is leiomyosarcoma

➣symptoms include obstruction, bleeding, or pain

➣criteria for malignancy: number of mitoses, nuclear atypia, pres-

ence of necrosis, cellularity

➣local or hematogenous spread

■Metastatic tumors

➣predominantly melanoma; also breast, lung, kidney, colon, cer-

vical, ovarian

➣may cause symptoms of obstruction, bleeding and pain

■Neuroendocrine tumors

➣gastrinoma, somatostatinoma, schwannoma, paraganglionoma

➣present with hormone-specific symptoms or as a mass le-

sion

tests

Basic Studies: Blood

■Early disease: usually normal

■Advanced disease: variable by tumor; microcytic anemia with GI

bleeding; elevated alkaline phosphatase and bilirubin with biliary

obstruction; elevated CEA with metastatic adenocarcinoma; ele-

vated beta- 2 -microglobulin, LDH, or monoclonal gammopathy with

lymphoma