A 21-year-old man was referred to our hospital for further examination of an abdominal tumor. He had a two-month history of abdominal fullness and lower abdominal pain, and was found to have a large abdominal tumor which was palpable and was confirmed by computed tomography (CT). Additional imaging examinations such as ultrasonography and magnetic resonance imaging revealed that the mass grew from the omentum and consisted of many small cysts and a solid component. From these findings it was diagnosed as lymphangioma and surgical resection of the tumor was conducted. The abdominal cavity was occupied by a large polycystic tumor which originated from the greater omentum and adhered to the stomach, spleen and pancreas. The greatest diameter of the tumor was 39cm and the section was cavernous, containing reddish-brown serous fluid. It was diagnosed histopathologically as cavernous lymphangioma without malignancy. Although omental lymphangioma is relatively rare, especially in adults, it should be considered as a possible cause of a rapidly growing abdominal mass.
We report 5 cases of non-Hodgkin lymphoma of the small intestine (S-NHL) treated with emergency operation. These cases showed three reasons for emergency operation :  massive hemorrhage with shock before diagnosis of S-NHL (Case 1),  obstruction of the small intestine before and during chemotherapeutic treatment for S-NHL (Cases 2 and 3), and  spontaneous perforation with peritonitis before diagnosis of SNHL or iatrogenic perforation following chemotherapy (Cases 4 and 5). For tumor discovery, double-balloon endoscopy of the small intestine was employed in 3 cases. Three tumors were histologically diagnosed before treatment, while 2 were histopathologically diagnosed using the resected specimens after emergency operation. An advanced stage of NHL was frequently observed. No surgical mortality accurred. We always consider the possibility of emergency operation before, during, and after the diagnosis and treatment of patients with SNHL.