Pancreatic pseudocysts simulating renal masses (report of two cases).
Pancreatic Pseudocysts, at times, may present at unusual sites, leading to difficulties in clinical diagnosis. Ranschoff described the first case of a pancreatic pseudocyst presenting with hematuria. Later on, a few odd reports were published on pancreatic Pseudocysts.,,, We wish to report 2 cases of pancreatic Pseudocysts which presented like renal or perirenal masses.
A 30 year old male presented with complaints of fixed pain in the right hypochondrium and flank, unrelated to meals and of 20 days' duration, There was a history of loss of weight and apetite, but no history of vomiting or alterations in the bowel habits. The patient did not have any urinary complaints and denied any history of jaundice in the past. He was a chronic alcoholic for 10 years. His general physical examination was normal. Abdominal examination revealed an intra-abdominal, firm, non-tender lump in the left hypochondrium extending to the left renal angle. It moved minimally with respiration, was bimanually palpable and dull on percussion. There was no organomegaly or free fluid in the abdomen. A tentative diagnosis of a left renal lump was made. On investigation, haemogram and urinalysis were within normal limits with BUN 8 mg% and blood sugar level 84 mg%. The liver function tests were normal. The serum amylase was 1655 units/dl. Skiagram of the chest showed minimal left pleural effusion. Plain skigram of the abdomen was normal. Intravenous pyelogram revealed no abnormality. Abdominal ultrasonogram revealed a sonolucent area around the left kidney.
A diagnostic aspiration of the mass with 20 gauge needle revealed brownish coloured fluid. Microscopic examination of the fluid showed acute inflammatory cells and the fluid amylase level was 1120 units/dl. The biochemical examination showed the fluid to be an exudate. Serum amylase at that time was 112 units/dl. A cavitogram showed a perinephric cavity.
Diagnosis of a pseudocyst of the pancreas was thus made and abdominal exploration was done through a left paramedian incision. There was a large cyst near the tail of the pancreas bulging through the root of the transverse mesocolon with the left colic vessels stretched over its surface.
The posterior wall of the cyst was formed by the left kidney. After confirming the diagnosis by needle aspiration, the cyst was opened and about 1000 ml of turbid fluid was removed. A Roux-en-Y cystojejunostomy was performed with a stent kept across the anastomosis and brought out through the distal loop.
The post-operative period was uneventful. Histopathological examination of the cyst was found to be consistent with a pancreatic pseudocyst. A cystogram through the stent on the 7th postoperative day revealed only a small cavity with rapid emptying of contents into the jejunum. The stent was removed after 3 weeks.
A 48 year old man came with history of pain in the epigastrium of two months' duration radiating to the left flank and neck, unrelated to meals. There was history of loss of weight and apetite. There was no history of vomiting, jaundice, alteration of bowel habits or urinary symptoms. The patient was a chronic alcoholic for over 12 years.
General physical examination was normal. On abdominal examination, the patient was found to have an intra-abdominal lump in the left hypochondrium extending to the left lumbar region but the renal angle was free. The lump was firm and non-tender, did not move with respiration and was not ballottable. The liver was just palpable and there was no other organomegaly or ascites.
A tentative diagnosis of pancreatic pseudocyst was made. On investigations, routine haemogram and urinalysis and liver functions were within normal limits. Amylase creatinine clearance ratio was 6.0. Fecal fat excretion was 6 gm/day (upper limit of normal). A barium meal stomach duodenum showed an extrinsic filling defect at the greater curvature with stomach stretching over it.
Abdominal exploration through a left paramedian incision was done and a cyst was found just below the spleen, close to its hilum with plenty of adhesions. The colon was pushed medially. On mobilizing the colon, a reniform cystic swelling was found. Left kidney was not palpable. Since it was difficult to decide the, organ of origin, i.e., kidney or pancreas, an intravenous pyelogram (I.V.P.) was done during the operation which revealed the left kidney to be normal thereby confirming the mass to be of pancreatic origin. A Roux-en-Y cystojejunostomy was performed. The post-operative recovery was uneventful.
Due to the close proximity of the pancreatic tail with the left renal hilum, pancreatic pseudocysts in this area and the left renal masses have been confused clinically. After Ranschoff drew the attention towards the existence of such a confusing picture, many clinical situations were described by various authors. Stone described a case where even on abdominal exploration, the two conditions could not be distinguished and unnecessary left nephrectomy was performed for a case of pancreatic pseudocyst. Baker et al discussed the diagnostic problems in such a situation and suggested needle aspiration, sonography, CAT scan and radiography as a multimodality approach to accurate diagnosis.
By virtue of its close relationship with the perirenal fascia of Gerota, pancreatic lesions can extend into that structure and produce signs, symptoms and investigational evidence of renal disease. Fascia of Gerota is a continuation of the transversalis fascia which splits at the lateral aspects of the kidneys to form renal fascia and fuses at the medial aspect to travel in front of the inferior vena cava and the aorta. The anterior layer of this fascia also fuses with the fascia surrounding the pancreas and the pancreas extends from the hilum of the left kidney to the hilum of the right kidney.
Inflammatory process of the tail of pancreas can give rise to inflammation of the pelvis of the left kidney and may lead to frank or microscopic haematuria. They can also cause renal colic and signs and symptoms of upper urinary tract infection. Both the cases described here are remarkable that they did not give rise to any symptoms referable to the genito-urinary system. However, many renal diseases are known to give rise to gastro-intestinal symptoms by virtue of reno-intestinal reflexes.
Abdominal examination usually fails to differentiate between masses of pancreatic and renal origin, particularly if the former extends into the renal angle as happened in our patients. Ballotment and bimanual palpation, the classical signs of renal masses, were present in our cases with pancreatic pseudocysts. Plain skiagram of abdomen was also of little diagnostic help in our cases. A normal I.V.P. ruled out possible involvement of the kidney in case 1 when intra-operative I.V.P. settled the issue in favour of a pseudocyst in case 2. I.V.P. may show distorted upper pole, displacement of the kidney or ureter or filling defects simulating malignancy.
Since chronic alcoholism and episodes of backache had given suspicion of pancreatic disease, a more non-invasive investigation was done in the form of an ultrasonogram in the first case. The ultrasonogram revealed normal pelvi-calyceal system and thus accurate pre-operative diagnosis was possible.
Coeliac angiogram may be of help as is the CAT scan in finding out the organ of origin. A simple, diagnostic, fine needle aspiration of the mass may also be of great help. A raised fluid amylase value almost confirms the diagnosis of a mass to be a pseudocyst. This was the investigation that settled the dilemma in our patients. Baker et al have also emphasized the importance of fine needle aspiration and estimation of its amylase content.