Primary Gastrointestinal Lymphoma

Abstract

The gastrointestinal tract (GIT) is the most common (30–40%) extranodal site involved in lymphoma. Although primary gastrointestinal lymphoma (PGIL) is a rare disease, comprising only 1–4% of gastrointestinal (GI) malignant tumors, its incidence is increasing. Different regions of the GIT are involved in different subtypes of PGIL with a various frequency that reflects the diversity of the causative agents and predisposing factors for each site and subtype of PGIL. Even though these malignant diseases are categorized under the common term of “lymphoma” they represent a heterogeneous group of malignant neoplasms which are different entities in terms of etiologic factors, predisposing conditions, pathogenesis, immunohistochemical profile, treatment strategy and prognosis. In this chapter the epidemiology of all subtypes of PGIL, factors and disorders contributing to the development of them, non-inherited and inherited conditions associated with a higher risk of them, diagnostic difficulties and pitfalls, and novel treatment strategies were comprehensively and concisely illuminated.

`Diagnostic Pitfalls in the Interpretation of Extranodal Lymphomas – a Case Series

“…In our study, Case 1 was a low-grade ENNHL with nodal high-grade transformation presenting as ulceroproliferative jejunal mass, misdiagnosed as adenocarcinoma, and surgically treated without repeating the previous inconclusive biopsy. This insists the importance of keeping low-grade ENNHL in differential diagnosis and also substantiates the opinion of repeat endoscopy biopsy if the findings are inconclusive [4]. Few indicators for high-grade transformation are high LDH, B symptoms, rapidly enlarging regional lymph node and PET scan that can pick high-grade lesions specifically [3,[5][6][7].…”

“…The symptoms should be specific pertaining to the extranodal site and be the dominant lesion during staging [3]. Dawson's 5-point criteria define primary gastrointestinal lymphoma [4]. GIT is the most common site for ENNHL, with stomach followed by intestine as the most common sites.…”

“…GIT is the most common site for ENNHL, with stomach followed by intestine as the most common sites. DLBCL and MZL of MALT are the most common high-grade and low-grade type, respectively [3,4]. The diagnosis of ENNHL usually has a high probability of misdiagnosis and diagnostic pitfalls both to the clinicians and pathologists.…”

“…The diagnosis of ENNHL usually has a high probability of misdiagnosis and diagnostic pitfalls both to the clinicians and pathologists. ENNHL patients usually are asymptomatic, do not have B symptoms, or may present with vague GI symptoms [4] Endoscopy also mostly shows non-specific findings such as gastritis and ulcer, few may show ulceroproliferative and nodular lesions similar to carcinoma [3,4]. Under these circumstances, usually, the clinicians do not consider the possibility of lymphoma, and even if any features of malignancy were observed, they usually point toward an epithelial malignancy, thereby needing histopathology for a definitive opinion.…”

“…Unless the pathologist is aware enough about the possibility of lymphoma and proceeds with IHC, the diagnosis would be missed. In this scenario, many GI lymphomas are subjected to surgical management on the assumption of carcinoma only to be diagnosed incidentally as lymphoma [4].…”