Pancreatic Insufficiency: This condition, where the pancreas does not produce enough digestive enzymes, is a common cause of greasy stools (steatorrhea) due to the malabsorption of fats.

Celiac Disease: An autoimmune disorder that causes the immune system to react to gluten, leading to inflammation and damage in the small intestine, which can result in malabsorption of fats and other nutrients.
Crohn's Disease: A type of inflammatory bowel disease (IBD) that can affect any part of the gastrointestinal tract, leading to symptoms including greasy stools due to malabsorption.
Small Intestine Bacterial Overgrowth (SIBO): A condition where there is an abnormal increase in the bacteria that inhabit the small intestine, which can lead to malabsorption and greasy stools.

Cystic Fibrosis: A genetic disorder that can lead to severe digestive problems, including pancreatic insufficiency and steatorrhea. Although less common, it's critical to diagnose due to its significant impact on health.
Whipple's Disease: A rare, systemic bacterial infection that can cause malabsorption, including steatorrhea, and has a high mortality rate if left untreated.
Lymphoma: Certain types of lymphoma, particularly those affecting the gastrointestinal tract, can cause malabsorption and greasy stools. Early diagnosis is crucial for effective treatment.

Abetalipoproteinemia: A rare inherited disorder that affects the absorption of fat and fat-soluble vitamins, leading to severe steatorrhea.
Short Bowel Syndrome: A condition that results from a significant loss of intestinal tissue, which can lead to malabsorption of nutrients, including fats.
Chronic Pancreatitis: Long-standing inflammation of the pancreas that can lead to pancreatic insufficiency and steatorrhea, though it's less common than other causes of greasy stools.