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A 76-year-old man presented with an insidious onset over 6 weeks of central abdominal pain associated with occasional vomiting. He had undergone left radical nephrectomy for cystadenocarcinoma 6 years earlier. Examination revealed an upper transverse abdominal incision without localised tenderness and slightly enlarged liver. Initial investigations showed deranged liver function tests and an amylase of 2886 IU/l. An initial diagnosis of pancreatitis was made. He was treated with intravenous fluids and bowel rest. His amylase remained persistently high throughout his stay in hospital. His renal clearance studies and plasma electrophoresis were normal. An abdominal ultrasound scan showed normal pancreas, common bile duct, and gall bladder; the left nephrectomy was noted. The ultrasonic appearance of the liver is shown in figure 1. Ultrasound-guided biopsy of the liver lesions was performed and the histology is shown in figure2.
- Suggest three causes of significant increase of serum amylase other than pancreatitis.
- Describe the findings on the ultrasound scan of the liver.
- What is the histological diagnosis?
Severe renal impairment, macroamylasemia, and other causes of acute abdomen can all cause significant increase of serum amylase.
The ultrasound scan of the liver showed a large complex cyst replacing most of the right lobe of the liver, its wall was irregular and several echogenic foci are seen.
The histology of the ultrasound scan-guided biopsy revealed fragments of papillary adenocarcinoma which would be compatible with metastases from the original renal tumour. The biopsy specimen was stained for amylase and found to contain significant amylase activity.
Traditionally, hyperamylasaemia is seen in acute pancreatitis, other causes of acute abdomen, and in severe renal impairment.1 Other less frequent causes are macroamylasaemia, following hepatic resections,2 and cardiopulmonary bypass,3 some cases of AIDS,4and rheumatoid arthritis.5 It has also been reported in association with various tumours, eg, phaeochromocytoma,6carcinoma of the lung,7 ovary, breast, and multiple myeloma.8 Adenocarcinoma of the kidney has been reported to produce amylase.9 Our patient has a metastatic adenocarcinoma of the kidney, high serum amylase, and significant amylase activity in his biopsy suggesting that the renal tumour is producing amylase ectopically. The possibility of such production was reinforced when macro-amylasaemia, a more frequent but benign cause of hyperamylasaemia, was excluded by plasma electrophoresis.
Renal cell carcinoma is known to be associated with both endocrine (eg, ectopic production of parathyroid hormone or erythropoietin) and nonendocrine paraneoplastic manifestations (eg, fever, cachexia, anaemia, and amyloidosis). However, our understanding of the underlying pathophysiology of these manifestations remains incomplete.
Metastatic adenocarcinoma of the kidney secreting ectopic amylase.
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