Likely to be non-cancerous
The CT scan
findings are suggestive of a cyst- meaning contains clear fluid.
It is most probably a benign lesion meaning not a cancer.
There is a possibility of a Lymphangioma
, meaning collection of the lymph fluid.
This can be removed by operation , as it may be the reason for pain in abdomen ans is of a fair size to be worried about. There is no medicinal treatment for such lesions .