GIST and Lymphoma

Gastrointestinal Stromal Tumors (GISTs)

Overview

• Definition: GISTs are rare tumors that arise from interstitial cells of Cajal or precursor cells in the GI tract. They are part of a group known as soft tissue sarcomas.
• Location: Most commonly found in the stomach (about 60%) or small intestine (about 30%), but they can occur in other parts of the GI tract or even outside the GI tract.
• Behavior: GISTs can be benign or malignant. Malignant GISTs are more likely to metastasize (spread) to other parts of the body, typically the liver and peritoneum.

Symptoms

• Abdominal pain or discomfort
• Gastrointestinal bleeding (e.g., blood in stool or vomit)
• Unexplained weight loss
• Palpable mass or swelling in the abdomen

Diagnosis

• Imaging Tests: CT scan, MRI, or PET scan to locate and evaluate the extent of the tumor.
• Endoscopy: May be used to visualize the tumor if it is accessible.
• Biopsy: A sample of the tumor tissue is taken and examined microscopically. GISTs are often diagnosed based on specific genetic mutations, such as in the KIT or PDGFRA genes.
• Immunohistochemistry: Tests for specific markers like CD117 (c-KIT) on the tumor cells.

Treatment

• Surgery: The primary treatment for localized GISTs is surgical removal. The goal is to remove the tumor and any affected surrounding tissue.
• Targeted Therapy: Drugs such as imatinib (Gleevec) and sunitinib (Sutent) are used for malignant or unresectable GISTs. These drugs target specific proteins involved in tumor growth.
• Radiation and Chemotherapy: Generally less effective for GISTs compared to other cancers.

Lymphoma

Overview

• Definition: Lymphoma is a type of cancer that originates in the lymphatic system, which is part of the body’s immune system. There are two main types:
  • Hodgkin Lymphoma (HL): Characterized by the presence of Reed-Sternberg cells.
  • Non-Hodgkin Lymphoma (NHL): A diverse group of lymphomas that do not have Reed-Sternberg cells. This group includes several subtypes such as diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, and mantle cell lymphoma.

Symptoms

• Swollen lymph nodes (usually painless)
• Unexplained fever
• Night sweats
• Weight loss
• Abdominal pain or fullness (if lymphoma involves the abdomen)
• Itchy skin

Diagnosis

• Imaging Tests: CT scans, PET scans, and MRI to identify and stage the lymphoma.
• Biopsy: A lymph node or other affected tissue is sampled to confirm the diagnosis and subtype of lymphoma.
• Blood Tests: To evaluate overall health and organ function.
• Bone Marrow Biopsy: To check if the lymphoma has spread to the bone marrow.

Treatment

• Chemotherapy: The primary treatment for many types of lymphoma, used to kill or inhibit the growth of cancer cells throughout the body.
• Radiation Therapy: Often used for localized lymphoma or as an adjunct to chemotherapy.
• Targeted Therapy: Drugs designed to target specific molecules involved in lymphoma growth (e.g., rituximab for B-cell lymphomas).
• Immunotherapy: Uses the body’s own immune system to fight cancer, including checkpoint inhibitors and CAR-T cell therapy.
• Stem Cell Transplant: May be considered for certain types of lymphoma, especially if they are resistant to other treatments.

Key Differences

• Origin: GISTs originate from connective tissue cells in the GI tract, while lymphomas originate from lymphocytes, a type of white blood cell.
• Treatment Approaches: GISTs often require surgery and targeted therapy, while lymphomas are primarily treated with chemotherapy, radiation, and increasingly with targeted and immunotherapies.