Gastric cancer is one of the most deadly cancers worldwide, especially in areas where
H. pylori infection rates are high.
4 types:
- Adenocarcinoma, which is the most common gastric cancer, arises from epithelial cells of the stomach mucosa.
- Lymphomas, which arise from lymphocytes: MALT (mucosa-associated lymphoid tissue) lymphoma is associated with H. pylori infection. Diffuse large B-cell lymphomas are aggressive and fast-growing.
- GI stromal tumors are mesenchymal tumors with variable morphology, including spindle and epithelioid cells.
- Carcinoid tumors arise from neuroendocrine cells; Type 1 is the most common type, and is characterized by elevated gastrin with parietal cell atrophy; it is associated with H. pylori infection. We can treat it with somatostatin analogs.
By far the most common type of gastric cancer.
Arises in the
stomach lining.
Gastric adenocarcinoma is further categorized as: Intestinal type (aka, well-differentiated) and diffuse (aka, undifferentiated) type.
Intestinal type
Intestinal type accounts for approximately 95% of gastric adenocarcinoma, and is associated with
H. pylori infection.
As its name suggests, its morphology is similar to intestinal adenocarcinoma, with abundant tubular and glandular elements.
On gross inspection we see a large, nodular mass arising from the stomach mucosa.
Diffuse adenocarcinoma
Can be hereditary, and is characterized histologically by discontinuous signet ring cells – note how the mucin-filled vacuole pushes the nuclei towards the edges of the cells.
Diffuse adenocarcinoma can lead to "linitis plastica" – we show that the lining of the stomach is thick and leathery ("linitis plastica" is also known as "leather bottle stomach").
Diffuse adenocarcinoma is associated with younger age of onset and has a worse prognosis than the intestinal type.
Risk factors:
Diets high in salt and processed meats and low in fruits and vegetables.
Cigarette smoking and heavy alcohol use.
Other gastric disorders, especially
H. pylori infection, gastritis, and Ménétrier disease (Ménétrier disease is characterized by overgrown mucosal folds, reduced acid secretion, and hypoalbuminemia).
Signs and symptoms:
Often present late in the course of disease, which contributes to poor prognosis.
The gastric tumor can push on the stomach contents, leading to some of the signs and symptoms associated with cancer, which include:
Early satiety and weight loss, dyspepsia, abdominal pain, nausea and potentially bloody vomiting, tarry stool, dysphagia, and odynophagia.
Diagnosis:
Often starts with blood and stool samples, but endoscopy and biopsy are necessary for confirmation; we can use abdominal imaging and endoscopic ultrasound to determine tumor size and metastasis.
Treatment:
Surgical resection and lymphadenectomy; some authors also recommend chemotherapy, radiation, or immunotherapy.
Clinical signs associated with gastric cancer - be aware that these examples are not specific to gastric cancer.
Troisier's sign occurs when cancer cells metastasize via the thoracic duct to Virchow's node (the left supraclavicular node); this can contribute to vascular thoracic outlet syndrome and neurogenic thoracic outlet syndrome.
Krukenberg tumors are ovarian tumors from metastasized gastric adenocarcinoma; tumors are typically bilateral and comprise mucin-secreting signet ring cells.
Sister Mary Joseph nodule refers to metastasis and formation of a subcutaneous periumbilical nodule.
Blumer shelf refers to a mass or thickening felt during a digital rectal exam, and is suggestive of metastasis to the rectouterine/rectovesicular pouch.
References in Full Tutorial.
