Brief Answer:
Small and fat cells in pancreas. MRI and Enzymes.

Detailed Answer:
Hello,
Welcome to XXXXXXX

I have gone through your query and understand your concern.

Atrophy of pancreas - pancreas looks smaller than normal size.
Fatty atrophy of pancreas- small pancreas with infiltration of fat cells in pancreas.

This is usually in Long standing diabetic patients and long standing Atherosclerosis patients (high cholesterol affecting blood vessels).

Chronic pancreatitis may finally end in Fatty atrophy.

Gall bladder removal may lead to chronic pancreatitis.
After gall bladder removal, Sphincter of oddi ( smooth muscles controlling the drainage of bile juice from gall bladder and pancreatic juice into small intestine) may get damaged.

This results in back pressure of bile and pancreatic juice on pancreatic tissue.
Ending in digestion of pancreatic tissue by bile and pancreatic juice.

This lead chronic pancreatitis and Fatty atrophy of pancreas.

Please check the pancreatic enzyme levels and correlate with normal range.

Do MRI Abdomen to look for the extent of the damage to pancreas.

The treatments are
1. Low fat diet
2. Fat soluble vitamins and calcium supplement
3. Supplemental pancreatic enzymes

Hope this helps.
Please reply for further queries.
Wishing you good health.

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