What Causes Swelling In The Lower Abdomen On The Left Side?

My mums had a hernia for years, in her umbilical area of her abdomen, and underwent keyhole surgery for cysts approx 10 years ago, however earlier this year she had an ongoing urinary tract infection which required 5 courses of antibiotics, she then came down with cellulitis which she was hospitalised for 4 weeks with. During this time she had developed swelling to the lower left side of her stomach area and which has since.swelled to the size of a basketball and which has literally made her left size so much larger than her right and which can been seen by just looking at her, its also caused her clothes to become too small and given her fatige ect as she feels like shes kicking a ball along as she walks. She had her kidneys, liver ect tested passing all with flying colours and we are left frustrated as noone has given her a diagnosis.