The presence of painless jaundice, weight loss, and a palpable, non-tender gallbladder (Courvoisier's sign) strongly suggests an obstructive process caused by a malignancy, most commonly pancreatic cancer at the head of the pancreas. This tumor compresses the common bile duct, leading to bile duct obstruction and gallbladder distension without inflammation. In contrast, gallstones typically cause painful jaundice and a contracted gallbladder. Thus, the combination of these signs is classic for malignant obstruction of the biliary tree, especially pancreatic adenocarcinoma. Early diagnosis is critical for potential surgical resection.

Reference: Sabiston Textbook of Surgery, Townsend et al., 21st Edition.