What are the other Names for this Condition? (Also known as/Synonyms)

• Undifferentiated Carcinoma of Stomach

What is Gastric Undifferentiated Carcinoma? (Definition/Background Information)

• Gastric Undifferentiated Carcinoma is an extremely rare and highly malignant epithelial tumor that develops in the stomach
• When a pathologist observes the tumor sample under the microscope, it is composed of anaplastic cells (undifferentiated) with no cytological or architectural differentiation
• The following subtypes of Gastric Undifferentiated Carcinoma are noted:
• Rhabdoid carcinoma
• Sarcomatoid carcinoma
• Carcinoma with osteoclast-like giant cells 
• Pleomorphic giant cell carcinoma 

Incidence:

• Gastric Undifferentiated Carcinoma is typically observed in adults
• Both males and females are affected
• It occurs worldwide and all races and ethnic groups are affected

Risk factors and Cause:

• The cause of Gastric Undifferentiated Carcinoma is currently unknown
• An association with loss of SMARCB1 (INI1), SMARCA4, and ARID1A genes has been documented

Signs and symptoms:

• The signs and symptoms vary from one individual to another 
• Most patients present with a necrotic fungating mass or as an ulcerated lesion seen on endoscopy

Diagnosis:

• Radiology - CT/MRI scan can be useful for staging of tumor
• Tissue biopsy of the mass is essential for definitive diagnosis
  • Pathology microscopic features: Pathological examination of the tissue may reveal diffuse sheets of anaplastic, large to medium-sized polygonal cells, with frequent pleomorphic tumor giant cells
  • ERBB2 (HER2) immunohistochemistry is recommended in all gastric carcinomas for which treatment is appropriate

Complications:

• Undifferentiated Carcinoma of Stomach can metastasize commonly to the liver
• Gastric obstruction can occur if the tumor is large 

Treatment:

• Surgical resection of tumor with lymph node resection is the mainstay of treatment
• Endoscopic mucosal resection can be done during the early stages

Prevention: Presently, it is not possible to prevent the formation of Gastric Undifferentiated Carcinoma.

Prognosis: 

• The prognosis of the tumor depends on the stage of the malignancy
• However, the prognosis is generally unfavorable, and most patients are known to die of the condition within a year
• Due to rarity of tumors and its highly-aggressive nature, the relevant prognostic factors are yet to be identified