A 29-year-old man presented with dull abdominal pain and a lump occupying almost the entire abdomen, four months after a fall from a height. Ultrasonography revealed a cystic lesion with debris occupying almost the entire abdomen. Diagnostic tap revealed brownish fluid. Exploration revealed a huge thick-walled cyst of the sigmoid mesocolon, which could be enucleated out entirely. Histology suggested it to be a false cyst.