Caroli's Disease or Choledochal Cyst: This condition involves a congenital anomaly of the bile ducts, which can lead to obstruction, hepatomegaly, and jaundice. The RIF (right iliac fossa) lump could be related to a palpable gallbladder (Courvoisier's sign) or a cystic structure related to the bile duct anomaly. Constipation might be secondary to the systemic effects of the disease or related to the anatomical disruption.

Gallbladder Cancer: This could explain the jaundice, hepatomegaly, and a palpable mass in the RIF, which might be a palpable gallbladder or metastasis. Constipation could be a symptom of advanced disease.
Cholangiocarcinoma: Similar to gallbladder cancer, cholangiocarcinoma could cause obstructive jaundice, hepatomegaly, and a mass might be palpable if the tumor is large enough. Constipation could be part of the symptom complex.
Pancreatic Cancer: Although typically presenting with a midline or left upper quadrant mass, a large pancreatic tumor could cause a palpable mass in the RIF, along with jaundice and hepatomegaly due to bile duct obstruction. Constipation might occur due to tumor effects on the intestines or as a paraneoplastic symptom.

Hepatocellular Carcinoma: While less common in some populations, hepatocellular carcinoma can present with hepatomegaly, jaundice, and a palpable mass. The RIF lump could be a metastasis or a separate process. Constipation could be a symptom of advanced disease.
Metastatic Disease to the Liver: Any primary cancer that metastasizes to the liver could cause hepatomegaly and potentially jaundice if there's significant liver dysfunction or bile duct obstruction. A palpable mass in the RIF could be a metastasis or the primary tumor if it's in a nearby organ.
Intra-abdominal Lymphoma: Lymphoma can cause hepatomegaly, jaundice (if there's liver involvement or bile duct obstruction), and a palpable mass. Constipation could be part of the systemic symptoms.

Polycystic Liver Disease: This condition involves multiple cysts in the liver, which can cause hepatomegaly. If large enough, these cysts could cause obstructive jaundice and a palpable mass. Constipation might be related to the mass effect on the intestines.
Budd-Chiari Syndrome: This is a rare condition caused by thrombosis of the hepatic veins, leading to hepatomegaly, ascites, and potentially jaundice. A palpable mass could be due to liver enlargement or thrombosed veins. Constipation might occur due to increased intra-abdominal pressure from ascites.