Lymphangiomatosis which is a benign tumor consisting of a cluster of dilated lymphatic channels, is very unusual. It is most often found in the neck and head. Less than 5% of cases are diagnosed intraabdominally. Herein a case in the abdomen in a 22-year-old man is reported. The clinical picture was with 7 days progression with constipation and abdominal pain associated with meals. An acute abdomen suggestive of perforated appendicitis was considered. In abdominal exploration, massive purulent fluid which consists of gastric content, pus and also fibrin process was seen among the intestinal loops. An active ulcer on the second part of duodenum and perforated ulcer anterior of this location were determined. There were disseminated multiple nodularities along the small bowel wall and mesenterium, and also different number and sized cauliflower-like polipoid masses from the ileo-caecal valve. Histopathological examination was reported as cavernous type lymphangiomatosis plus acute inflammatory reaction. Lymphangioma is difficult to be considered in the differential diagnosis because of the silent clinical course and lack of awareness of the clinical and morphological features. Our case report and review of the literature suggest that lymphangiomatosis is a very rare entity which could be seen with acute abdomen.