According to Official Guinness Records,
A benign cystic hygroma weighing 1.2 kg (2 lb 9 oz) was removed successfully from the neck of a baby boy (India, b. 5 March 2003) by a team lead by Dr. Palin Khundongbam at Shija Hospitals and Research Institute, Imphal, Manipur, India on 17 March 2003. The tumour represented 40% of the child's total bodyweight of 3 kg (6 lb 8.5 oz).
For a complete list of 2003 records, please visit 2003 Guinness Records in India.