Primary gastric lymphoma: A report of 16 pediatric cases treated at a single institute and review of the literature.

Gastrointestinal tract is the most common extranodal site for childhood non-Hodgkin lymphomas (NHLs). However, primary gastric lymphoma (PGL) is very rare. We report our experience with PGL. Between 1972 and 2019, patients with PGL among 1696 NHL cases were evaluated retrospectively. Patient characteristics, treatments, and survival rates were recorded. We also reviewed the cases reported in literature. There were 16 PGL (11 males, five females) cases with a median age of 10 years. Most frequent complaints, similarly to the literature, were pain and vomiting. Hematemesis/melena and anemia were present in 20% of patients. Most common tumor location was antrum. Histopathological subtypes were Burkitt and non-Burkitt B-cell lymphoma in 43.75% and marginal zone lymphoma (MZL) in 6.25% of cases while mucosa-associated lymphoid tissue (MALT) and low-grade lymphomas constitute 15.3% of cases reported in the literature. In our series, Helicobacter pylori (H. pylori) was analyzed in only the case with MZL and found to be positive. However, H. pylori positivity was reported in 75% of the cases in the literature. H. pylori eradication, chemotherapy, and radiotherapy were applied in one, 14, and five patients. Subtotal gastrectomy with gastroduodenostomy/jejunostomy was performed in three patients. Gastrojejunostomy was done without tumor resection in two patients. Nine patients lived without disease for a median of 59 (12-252) months. Five-year EFS and OS were 69.6% and 64.3%, respectively. PGL constitutes 0.94% of our NHL cases. Interestingly, most of the cases in the literature were from Turkey. While adult PGL is mostly MALT lymphoma, most pediatric cases had high-grade histopathology. Although surgery and radiotherapy were applied earlier, chemotherapy alone is sufficient.