Mesenteric cysts are rare and occur in patients of any age. They are asymptomatic and found incidentally or during the management of their complications. They commonly originate from the small bowel mesentery, although a proportion has been found to originate from the mesocolon (24%) and retroperitoneum (14.5%). A mesenteric cyst originating in the sigmoid mesocolon is a very rare finding.

Splenic diseases are rare. Tumours of the spleen are classified as either benign or malignant. Primary benign tumours of the spleen are extremely rare, identified on surgery and autopsy, accounting for <0.007% of all splenic tumours. Splenic lymphangiomas are benign cystic tumours resulting from congenital malformations of the lymphatic system that appear as a single or multiple lesions of the spleen. It mainly affects children and is rarely manifested after the age of 20 years of age. We report a case of cystic lymphangioma of spleen in a 40-year-old woman admitted with a huge mass in the abdomen, which on imaging found to be a cystic mass arising from spleen. On laparotomy the spleen was found occupying a major part of the abdomen. Splenectomy was performed and histopathological examination revealed it to be a cystic lymphangioma of spleen. This case report emphasises on the rarity of the case at this age and the sheer size of the tumour, being largest until as per our knowledge.