What to do when you suspect gastrointestinal lymphoma: a pathologist's perspective.

Although primary gastrointestinal (GI) lymphomas are an infrequent occurrence and represent 1%-4% of the malignant tumors of the GI tract, secondary involvement of the GI tract by lymphoma is not uncommon. Several controversies remain about the prognostic stratification and the optimal treatment modalities for these lymphomas. A crucial component of answering these questions is an accurate and complete characterization of the tumor. The currently used World Health Organization classification of hematologic malignancies requires integration of morphologic, immunophenotypic, and genotypic features to define a disease type. Through the use of a representative case we highlight how this information is used for the appropriate diagnosis of a GI lymphoma. We also discuss the clinical features, including radiologic and endoscopic findings in patients presenting with a GI lymphoma. The review is a pathologist's perspective on what to do when suspecting a lymphoma of the GI tract.