Middle Eastern intestinal lymphoma: a morphological and immunohistochemical study.

Area of Science:

• Gastroenterology
• Oncology
• Immunology

Background:

• Gastrointestinal lymphomas in the Middle East present unique histological and immunohistochemical characteristics.
• Understanding these variations is crucial for accurate diagnosis and treatment strategies.

Purpose of the Study:

• To classify Middle Eastern gastrointestinal lymphomas based on histology and immunoperoxidase staining.
• To compare the immunophenotypes of these lymphomas with their European counterparts.
• To elucidate the cellular origin of Mediterranean lymphoma (MTL).

Main Methods:

• Analysis of 31 Middle Eastern gastrointestinal lymphoma cases using conventional histology.
• Immunoperoxidase staining with anti-immunoglobulin (Ig) and anti-J chain antisera on paraffin sections.
• Categorization into Burkitt type, follicle center cell (FCC) lymphoma, and Mediterranean lymphoma (MTL).

Main Results:

• Three histological categories were identified: Burkitt type (8 cases), FCC lymphoma (15 cases), and MTL (3 cases).
• FCC lymphomas showed distinct immunophenotypic differences from European cases, with isolated light chain or J chain detection.
• Mediterranean lymphoma cases exhibited a plasma cell infiltrate positive for alpha and J chains, while invasive FCC-like cells were negative.
• Intracellular alpha chain inclusions were noted in two FCC cases.

Conclusions:

• The three identified histological categories represent the primary types of gastrointestinal lymphoma in the Middle East.
• Mediterranean lymphoma appears to be of follicle center cell origin, despite its distinct presentation.
• Immunohistochemical analysis reveals significant variations in immunoglobulin expression within Middle Eastern lymphomas compared to European ones.