Pathology of GIT- Neoplastic diseases of Stomach

Pathology of GITNeoplastic Diseases of The Stomach

Prof. Dr. Faeza Aftan Dept of Pathology Col of Med Aliraqia University
Oct. 7 2015

GASTRIC TUMORS

BENIGN:POLYPS (HYPERPLASTIC vs. ADENOMATOUS)LEIOMYOMAS (Same gross and micro as sm. muscle)LIPOMAS (Same gross and micro as adipose tissue)MALIGNANT(ADENO)CarcinomaLYMPHOMAPOTENTIALLY MALIGNANTG.I.S.T. (Gastro-Intestinal “Stromal” Tumor)CARCINOID (NEUROENDOCRINE)

WHO GASTRIC NEOPLASMS

Epithelial Tumors: Adenomatous polyps, Adenocarcinoma, (> 90%) Carcinoid (neuroendocrine) Nonepithelial Tumors: Leiomyo(sarc)oma, GIST. Malignant Lymphomas: (5%)

Gastric Polyps

Inflammatory and Hyperplastic Polyps Form 75% of all gastric polyps Chronic, H. pylori gastritis Multiple < 1cm Dysplasia, Size (> 1.5cm) & No. Gastric adenoma 10% of gastric polyp +ve Dysplasia (Low or high grade) Chronic, atrophic gastritis & Intest metaplasia.

LEIOMYOMAS

Gastric AdenocarcinomaPathogenesis
H. Pylori EBV Mutation in CDH1.

Chronic Inflammation and Cancer

Ch. inflammation result in production of cytokines, (IL-1β) &(TNF). which stimulate the growth of transformed cells. Ch. inflammation result in production of Reactive Oxygen Species (ROS), which promote genomic instability in cells. thus predisposing to malignant transformation.Ch. Inflammation increase the pool of stem cells, which become subject to the effect of mutagens.

Gastric AdenocarcinomaRISK FACTORS

Gastric Adenocarcinoma
Early gastric cancer ; Tumor limited to Mucosa & Submucosa. Mass endoscopic screening programs. 5 years survival > 90% Invasive gastric adenoca. 5 years survival < 20%.

Gastric AdenocarcinomaGrowth pattern

Exophytic mass Ulcer Diffuse thickening, diffuse infiltration of gastric wall (Linitis plastica).

Gastric AdenocarcinomaGrowth pattern

linitis plastica

Chronic gastric ulcer Malignant gastric ulcer

Gastric adenocarcinomaLINITIS PLASTICADiffuse type.
LEATHER BOTTLE


Gastric adenocarcinoma
Clinical presentation: Early symptoms resemble those of ch. gastritis, (dyspepsia, dysphagia, & nausea). Advanced stages manifestations weight loss, anorexia, altered bowel habits, anemia, and hemorrhage.


Lauren Classification: A. Intestinal or glandular type gastric carcinoma: glandsB. Diffuse type; signet ring cells
A
B
Gastric adenocarcinoma

Signet ring cell

Gastric Lymphoma; Extranodal lymphomas arise in any tissue, most in GIT, most in stomach. MALT 5% of all gastric malignancies. B-Cell lymphoma.


Carcinoid Tumor;Arise from neuroendocrine organs, NE cells (G – cells).Majority are found in the GIT , > 40% in S. Intest.Tracheobronchial & lung.called “carcinoid” because they are slower growing than carcinomasWHO classification; low- or intermediate grade NE tumors

Carcinoid Tumor

Prognostic factors Site. (Malignant in Jeujenum, Benign in appendix). Size Depth of invasion. Mitosis. Necrosis Neuroendocrine carcinoma; High-grade NE tumors, shows necrosis, most common in the jejunum

The most important prognostic factor for GIT carcinoid tumors is location:

• Foregut carcinoid tumors, (stomach, duodenum & esophagus) , rarely metastasize and generally are cured by resection. • Midgut carcinoid tumors (jejunum & ileum), often are multiple and tend to be aggressive. • Hindgut carcinoids (appendix & colorectum) typically are discovered incidentally. In the appendix are almost uniformly benign. Rectal carcinoid tend to produce polypeptide hormones, they only occasionally metastasize

Carcinoid syndrome

The carcinoid syndrome is caused by vasoactive substances secreted by the tumor. Thus, carcinoid syndrome occurs in less than 10% of patients and is strongly associated with metastatic disease.


Intramural or Submucosal yellow tumor. and with intense desmoplastic reaction that may cause kinking of the bowel and obstruction.
Carcinoid Tumor

G.I.S.T. TUMORS

Can behave and/or look benign or malignantUsually look like smooth muscle, i.e., “stroma”Are POSITIVE for c-KIT (CD117)the tumor cells are derived from the interstitial cells, of Cajal, a “neural” type of cell.