Gastrointestinal lymphomas: Pattern of distribution and histological subtypes: 10 years experience in a tertiary centre in South India.

Background and Aim: Gastrointestinal tract (GIT) is one of the major sites of extra-nodal lymphomas constituting 10-15% of all non-Hodgkin's lymphoma cases and about 30-40% of extra-nodal lymphomas. Considerable variation exists in the literature with respect to incidence of the various histological subtypes and sites of involvement. This study was undertaken to ascertain the anatomic distribution, histological subtypes and sites of all GIT lymphomas presenting to a tertiary referral hospital in southern India. Materials and Methods: The histological material of 361 patients over a period of 10 years (2001-2010), with histopathological diagnosis of lymphoma involving the GIT (both primary and secondary), was analyzed retrospectively. All lymphomas were reclassified according to the World Health Organization 2008 classification. Results: These 361 cases include 336 primary and 25 cases of lymphomas, where the involvement was secondary. Primary lymphomas consisted of 267 males (79.64%) and 68 females (20.24%) with a male:female ratio of 3.93:1. The mean age was 45 years (range 3-88). Diffuse large B-cell lymphoma (DLBCL) was the commonest subtype (222 cases; 66.71%), followed by low-grade marginal zone lymphoma of the mucosa associated lymphoid tissue (MALT) type (34 cases; 10.12%) and Burkitt's lymphoma (35 cases; 10.48%). The commonest site was stomach (180 cases; 53.57%), followed by small intestine (79 cases; 23.51%) and large intestine (68 cases; 20.23%), respectively. There were some uncommon types of GIT lymphomas documented during the study. Conclusion: In this largest retrospective single centre study from India, we establish that the pattern of distribution of primary GIT lymphomas (PGLs) in India is similar to the western literature in that the stomach is the commonest site of PGL and DLBCL is the commonest histological subtype. Immunoproliferative small intestinal disease cases were seen in this study, which is uncommon in the west.

Gastrointestinal stromal tumors: A 7-year experience from a tertiary care hospital.

Background: Gastrointestinal stromal tumor (GIST), now the most common mesenchymal tumor of the gastrointestinal tract (GIT), has been frequently studied, especially with regard to its successful targeted therapy using imatinib mesylate. Aim: Our aim was to describe the clinicopathological features of a large number of cases from a tertiary care hospital in India and report on the follow-up after treatment of some of the cases, comparing them with series described in the west. Design: This is a retrospective study of cases encountered over a 7-year period (1999-2005). Results: Ninety-two cases of GIST were studied, which made up the largest group (52.8%) of mesenchymal tumors of the GIT, with smooth muscle tumors comprising 38.1%, the next large group. GISTs were almost equally prevalent in the stomach and the small intestine, unlike in most studies where stomach is the most common site. GIST may be considered as a cause of bleeding when upper and lower GI endoscopy is normal. Ninety-five percent of the GISTs were positive for CD117 (KIT), as is known. A majority of them (70.4%) were of the high-risk malignant category, unlike most studies where high-risk tumors make up 30-45%. Histologically, the majority had a pure spindle cell morphology and skenoid fibers were rare. Follow-up of 11 cases, the majority with high-risk tumor, treated with adjuvant imatinib for 6 months after surgical resection showed stable disease for periods from 2 to 5 years. However, 11 cases treated with imatinib for longer than 6 months had a poorer outcome due to recurrent, metastatic, or inoperable disease. Conclusion: In our study of a large number of GISTs, which were equally prevalent in the stomach and small intestine, the majority were of the high-risk malignant category and of pure spindle cell morphology. Limited numbers had follow-up after imatinib therapy, which showed in one group treated for 6 months, after resection of high-risk GIST, stable disease for periods ranging from 2 to 5 years. Molecular studies and larger numbers are required for meaningful conclusions to be drawn.