A Single Neoplastic Clone in Sequential Biopsy Specimens from a Patient with Primary Gastric-Mucosa-Associated Lymphoid-Tissue Lymphoma and Sjogren's Syndrome

Abstract

Low-grade B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) that occur in the stomach, small intestine, salivary gland, lung, and thyroid are indolent neoplasms characterized by a prolonged clinical course and persistent disease at the site of origin¹. The mechanism by which the neoplastic cells remain committed to a single site, the presence or absence of neoplastic-cell traffic or homing, and the specific dissemination of MALT lymphomas to other mucosal sites² are all properties of these lymphomas that are poorly understood. Investigation of these features has been hampered by the absence of a tumor-cell-specific marker with which to examine the progression of the tumor in sequential biopsy specimens. The presence of a neoplastic clonal population of B lymphocytes can be inferred from the detection of the restriction of kappa or lambda immunoglobulin light chains in tissue sections³. However, this technique cannot easily detect small neoplastic clones in a reactive lymphoid population, nor can it establish a clonal relation between neoplastic cells in serial biopsy specimens. Recent success in using the polymerase chain reaction (PCR) to demonstrate clonal immunoglobulin-gene rearrangement has made it possible to detect small monoclonal B-cell populations in paraffin-embedded tissue⁴. This has provided a marker with which to follow the progress of a neoplastic B-cell clone in serial archival biopsy specimens. In this study we used PCR to analyze sequential formalin-fixed, paraffin-embedded specimens from the stomach, lip, and bone marrow of a patient with a primary low-grade gastric B-cell MALT lymphoma and Sjogren's syndrome.