International Journal of Pancreatology, pp. 195-198 vol. 11, no. 3, June 1992 9 Copyright 1992 by The Humana Press Inc. All rights of any nature whatsoever reserved. 0169-4197/92111:195-198t$2.00
Case Report
Urinoma Masquerading as Pancreatic Pseudocyst J. A. Sorgman, E. Langevin, and P. A. Banks* Departments of Radiology and Medicine, Division of Gastroenterology, St. Elizabeth's Hospital of Boston, Tufts University School of Medicine, Boston, MA
Summary In this article, we report on a patient with recurrent pancreatitis who had received multiple celiac plexus injections for control of pain, and then developed a cystic mass adjacent to the body and tail of the pancreas suggestive of a pancreatic pseudocyst. The cystic mass proved to be a urinoma. The distinction between pancreatic pseudocyst and urinoma was made by CT scan with intravenous contrast utilizing delayed films, which demonstrated leakage of contrast into the cystic structure. This is the first report of a urinoma that resembled a pancreatic pseudocyst. Key Words: Pancreatic pseudocyst; urinoma; chronic pancreatitiso
Introduction
trol of chronic pain, most recently 3 wk before admission, and was pain-free on presentation. She denied use of alcohol or tobacco. Physical examination revealed a thin woman in no acute distress; her vital signs were normal. Significant physical findings were confined to the abdomen, which was nondistended and contained no masses but was slightly tender to deep palpation in the epigastrium. A succussion splash was appreciated, and rectal examination was negative for occult blood. Admission laboratory studies, inluding CBC, amylase, lipase, and full chemistry profile, were normal with the exception of an alkaline phosphatase of 175 IU (normal 43-122 IU). Survey film of the abdomen was normal. An upper GI series revealed complete obstruction in the distal duodenum that was thought to be extrinsic. An abdominal CT scan with iv contrast demonstrated a large, cystic structure in the vicinity of the pancreatic tail and left kidney, suggestive of a pan-
Cystic structures that develop near the pancreas among patients with pancreatitis usually prove to be pancreatic pseudocysts. In this report, we present a patient with a urinoma that resembled a pancreatic pseudocyst.
Case Report The subject is a 51-year-old woman with a 3-wk history of unremitting nausea and vomiting. Past medical history was significant for peptic ulcer disease, depression, and recurrent pancreatitis of unclear etiology. She was treated u n s u c c e s s f u l l y with sphincteroplasty of sphincter of Oddi. She had undergone numerous celiac plexus blocks for conReceived October 21, 1991; Revised December 2, 1991; Accepted D e c e m b e r 12, 1991 *Author to whom all correspondence and reprint requests should be addressed: Chief o f Gastroenterology, St. Elizabeth's Hospital, 736 Cambridge Street, Boston, MA 02135
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Fig. 1. CT scan with oral and iv contrast. There is a well defined ovoid cystic structure (arrowheads) with a thick capsule that is minimally irregular. The contents of the cystic structure have the density of water. The structure is located between the stomach, left kidney, pancreatic tail, and spleen. There is dilatation of the left renal pelvis. The stomach, duodenum, and common bile duct (white arrow) contain air and oral contrast material. creatic pseudocyst (Fig. 1). Delayed scanning without additional iv contrast showed opacification of the dilated renal pelvis and filling of the cystic structure with contrast-containing urine (Fig. 2). Additional scans taken in the lateral position demonstrated extravasation of contrast from the renal pelvis into the cystic structure. These CT findings established the diagnosis of urinoma. A cystoscopy with retrograde stent placement was unsuccessful because of a complete left upper-ureteral obstruction. "I'Itree days after placement of a percutaneous nephrostomy tube, a CT scan showed that the urinoma had decreased in size. Because of persistent fevers and a nephrostogram that demonstrated a fistula to the splenic flexure of the colon, the patient underwent a laparotomy, which confirmed the presence of an infected urinoma that obstructed the duodenum and was adherent to the colon, spleen, and tail of pancreas. The patient underwent a radical left nephrectomy, drainage of urinoma, transverse loop colostomy, and retrocolic gastrojejunostomy.
Discussion A urinoma is a cystic structure formed by the extravasation of urine into the fascial planes near the
International Journal of Pancreatology
kidney. This entity has been given many names, including pararenal pseudocyst, uriniferous pseudocyst, and pseudohydronephrosis (1). Urinomas are generally the result of either blunt abdominal trauma or penetrating injuries to the kidney or ureter. Unusual causes include tumor, renal calculus, iliac artery pseudoaneurysm, and bladder obstruction (1-3). "INs is the first case in the literature of a urinoma following celiac plexus injection. Urinomas can develop in two settings: In the ftrst, ureteral obstruction causes increased pressure within the renal pelvis, allowing leakage of urire (2). Extravasation of urine leads to lipolysis and inflammation within the soft tissue surrounding the kidney (4). The ureter may become secondarily involved in this inflammatory response, accentuating the ureteral obstruction and perpetuating the leakage of urine (5). Eventually, the inflammatory response produces a thick, fibrous capsule that contains the urine collection (4). In the second setting, renal trauma results in extravasation of urine from the renal pelvis or ureter. In most instances of trauma, leakage of urine is self-limited. However, if there is either transient or fixed ureteral obstruction, such as by a blood clot within the ureter, extravasation of urine persists. The resulting inflammatory response leads to the creation of a urinoma (5).
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197
Fig. 2. CT scan obtained 6 h later. This delayed scan obtained without additional contrast reveals filling of the left renal pelvis and cystic structure with urine that contains contrast. Opacification of the cystic structure establishes the diagnosis of a urinoma. The exact site of extravasation from the left renal pelvis to the urinoma was identified on other scans.
In this case, the needle appears to have pierced the left renal pelvis, which is in close proximity to the celiac plexus. The initial ureteral obstruction may have been a blood clot, whereas the persistent obstruction appears to have been caused by the inflammatory response to urine within soft tissues around the ureter. In most cases of urinoma, urine collects within Gerota's fascia and presents as a perirenal urinoma (5). In cases of penetrating trauma, the urine can extravasate through the tract made by the sharp object and collect in spaces defined by other fascial planes. In this case, the urine collected in an area anterior to the kidney and adjacent to the pancreatic tail. Radiologic evaluation of a urinoma has been well described in the literature. A plain film of the abdomen may reveal a soft tissue mass in the lateral abdomen (1). Abdominal ultrasound may show a large, cystic structure in the vicinity of the kidney. Excretory or retrograde urography may demonstrate extravasation of urine into a mass displacing the kidney and ureter. Abdominal CT scan is helpful in distinguishing a urinoma from such entities as hematoma and abscess and in providing precise information about the relation of the urinoma to neighboring structures. CT scan typically shows a cystic structure with a thickened
International Journal of Pancreatology
smooth wall. Attenuation of the cyst fluid generally ranges from -10 to +20 HU and is very homogeneous (3, 6). Anterior and superior displacement of the kidneys, as well as hydronephrosis, are common findings in perirenal urinomas. Delayed films after the administration of iv contrast usually demonstrate extravasation of urine that contains contrast into the urinoma with consequent opacification of the cyst-like structure (3). The precise site of the leak may be delineated, as in this case (1, 7). The wall of the urinoma enhances mildly with iv contrast because of the inflammation and neovascularity of the pseudocapsule (6). The differential diagnosis of urinoma includes hematoma and abscess. In general, hematoma can be distinguished from urinoma on CT scan by its higher attenuation coefficients (+20 to +80 vs -10 to +20), penetration through fascial planes, and absence of hydronephrosis (3). An abscess is often irregular and heterogeneous, can contain gas and traverse the tissue planes, and has a wall that may enhance to a greater degree than does the pseudocapsule of a urinoma (6). This is the first reported case of a urinoma that resembles a pancreatic pseudocyst on abdominal CT scan. This distinction would have particular clinical relevance following blunt abdominal trauma, which
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could lead either to traumatic pancreatitis with formation of a pseudocyst or to renal injury with formation of a urinoma. Both entities may be adjacent to the pancreatic body and tail, and the wall of both structures may enhance weakly with iv contrast. The distinction between pancreatic pseudocyst and urinoma can be made on CT scan with iv contrast if delayed films are obtained. If the cystic structure is a pseudocyst, there is no enharw~ment of the fluict If the structure is a urinoma, there is uniform enhancement of the fluid on delayed films, and the precise site of extravasation may be seen.
References 1 Mclnerney D, Jones A, Roylance J. Urinoma. Clin Radiol 1977; 28: 345-351. 2 Rose BS, Ragosin R, LaRoga JL, Drago JR. Pyelosinus extravasation and urinoma associated with malignancy: computed tomography demonstration. Urology 1988; 31: 349-353. 3 Healy ME, Teng SS, Mogg AA. Uriniferous pseudocyst: computed tomographic findings. Radiology 1984; 153: 757762. 4 Razzaboni G. Richerche sperimentali sulla Pseudoidnefrosi. Archivo Italiano di Chirurgia 1922; 6: 365. 5 Meyers MA. Uriniferous perirenal pseudocyst: new observations. Radiology 1975; 117: 539-545. 6 Lang EK, Glorioso L. ~I. Management of urinomas by percutaneous drainage procedures. Radial Clinics of North America 1986; 24: 551-559. 7 Mitty HA. CT for diagnosis and management of urinary extravasation. Am JRadiol 1980; 134: 497-501.
International Journal of Pancreatology
Volume 11, 1992
Case Report
Urinoma Masquerading as Pancreatic Pseudocyst J. A. Sorgman, E. Langevin, and P. A. Banks* Departments of Radiology and Medicine, Division of Gastroenterology, St. Elizabeth's Hospital of Boston, Tufts University School of Medicine, Boston, MA
Summary In this article, we report on a patient with recurrent pancreatitis who had received multiple celiac plexus injections for control of pain, and then developed a cystic mass adjacent to the body and tail of the pancreas suggestive of a pancreatic pseudocyst. The cystic mass proved to be a urinoma. The distinction between pancreatic pseudocyst and urinoma was made by CT scan with intravenous contrast utilizing delayed films, which demonstrated leakage of contrast into the cystic structure. This is the first report of a urinoma that resembled a pancreatic pseudocyst. Key Words: Pancreatic pseudocyst; urinoma; chronic pancreatitiso
Introduction
trol of chronic pain, most recently 3 wk before admission, and was pain-free on presentation. She denied use of alcohol or tobacco. Physical examination revealed a thin woman in no acute distress; her vital signs were normal. Significant physical findings were confined to the abdomen, which was nondistended and contained no masses but was slightly tender to deep palpation in the epigastrium. A succussion splash was appreciated, and rectal examination was negative for occult blood. Admission laboratory studies, inluding CBC, amylase, lipase, and full chemistry profile, were normal with the exception of an alkaline phosphatase of 175 IU (normal 43-122 IU). Survey film of the abdomen was normal. An upper GI series revealed complete obstruction in the distal duodenum that was thought to be extrinsic. An abdominal CT scan with iv contrast demonstrated a large, cystic structure in the vicinity of the pancreatic tail and left kidney, suggestive of a pan-
Cystic structures that develop near the pancreas among patients with pancreatitis usually prove to be pancreatic pseudocysts. In this report, we present a patient with a urinoma that resembled a pancreatic pseudocyst.
Case Report The subject is a 51-year-old woman with a 3-wk history of unremitting nausea and vomiting. Past medical history was significant for peptic ulcer disease, depression, and recurrent pancreatitis of unclear etiology. She was treated u n s u c c e s s f u l l y with sphincteroplasty of sphincter of Oddi. She had undergone numerous celiac plexus blocks for conReceived October 21, 1991; Revised December 2, 1991; Accepted D e c e m b e r 12, 1991 *Author to whom all correspondence and reprint requests should be addressed: Chief o f Gastroenterology, St. Elizabeth's Hospital, 736 Cambridge Street, Boston, MA 02135
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Sorgman, Langevin, and Banks
Fig. 1. CT scan with oral and iv contrast. There is a well defined ovoid cystic structure (arrowheads) with a thick capsule that is minimally irregular. The contents of the cystic structure have the density of water. The structure is located between the stomach, left kidney, pancreatic tail, and spleen. There is dilatation of the left renal pelvis. The stomach, duodenum, and common bile duct (white arrow) contain air and oral contrast material. creatic pseudocyst (Fig. 1). Delayed scanning without additional iv contrast showed opacification of the dilated renal pelvis and filling of the cystic structure with contrast-containing urine (Fig. 2). Additional scans taken in the lateral position demonstrated extravasation of contrast from the renal pelvis into the cystic structure. These CT findings established the diagnosis of urinoma. A cystoscopy with retrograde stent placement was unsuccessful because of a complete left upper-ureteral obstruction. "I'Itree days after placement of a percutaneous nephrostomy tube, a CT scan showed that the urinoma had decreased in size. Because of persistent fevers and a nephrostogram that demonstrated a fistula to the splenic flexure of the colon, the patient underwent a laparotomy, which confirmed the presence of an infected urinoma that obstructed the duodenum and was adherent to the colon, spleen, and tail of pancreas. The patient underwent a radical left nephrectomy, drainage of urinoma, transverse loop colostomy, and retrocolic gastrojejunostomy.
Discussion A urinoma is a cystic structure formed by the extravasation of urine into the fascial planes near the
International Journal of Pancreatology
kidney. This entity has been given many names, including pararenal pseudocyst, uriniferous pseudocyst, and pseudohydronephrosis (1). Urinomas are generally the result of either blunt abdominal trauma or penetrating injuries to the kidney or ureter. Unusual causes include tumor, renal calculus, iliac artery pseudoaneurysm, and bladder obstruction (1-3). "INs is the first case in the literature of a urinoma following celiac plexus injection. Urinomas can develop in two settings: In the ftrst, ureteral obstruction causes increased pressure within the renal pelvis, allowing leakage of urire (2). Extravasation of urine leads to lipolysis and inflammation within the soft tissue surrounding the kidney (4). The ureter may become secondarily involved in this inflammatory response, accentuating the ureteral obstruction and perpetuating the leakage of urine (5). Eventually, the inflammatory response produces a thick, fibrous capsule that contains the urine collection (4). In the second setting, renal trauma results in extravasation of urine from the renal pelvis or ureter. In most instances of trauma, leakage of urine is self-limited. However, if there is either transient or fixed ureteral obstruction, such as by a blood clot within the ureter, extravasation of urine persists. The resulting inflammatory response leads to the creation of a urinoma (5).
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Urinoma Mimicking Pancreatic Cyst
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Fig. 2. CT scan obtained 6 h later. This delayed scan obtained without additional contrast reveals filling of the left renal pelvis and cystic structure with urine that contains contrast. Opacification of the cystic structure establishes the diagnosis of a urinoma. The exact site of extravasation from the left renal pelvis to the urinoma was identified on other scans.
In this case, the needle appears to have pierced the left renal pelvis, which is in close proximity to the celiac plexus. The initial ureteral obstruction may have been a blood clot, whereas the persistent obstruction appears to have been caused by the inflammatory response to urine within soft tissues around the ureter. In most cases of urinoma, urine collects within Gerota's fascia and presents as a perirenal urinoma (5). In cases of penetrating trauma, the urine can extravasate through the tract made by the sharp object and collect in spaces defined by other fascial planes. In this case, the urine collected in an area anterior to the kidney and adjacent to the pancreatic tail. Radiologic evaluation of a urinoma has been well described in the literature. A plain film of the abdomen may reveal a soft tissue mass in the lateral abdomen (1). Abdominal ultrasound may show a large, cystic structure in the vicinity of the kidney. Excretory or retrograde urography may demonstrate extravasation of urine into a mass displacing the kidney and ureter. Abdominal CT scan is helpful in distinguishing a urinoma from such entities as hematoma and abscess and in providing precise information about the relation of the urinoma to neighboring structures. CT scan typically shows a cystic structure with a thickened
International Journal of Pancreatology
smooth wall. Attenuation of the cyst fluid generally ranges from -10 to +20 HU and is very homogeneous (3, 6). Anterior and superior displacement of the kidneys, as well as hydronephrosis, are common findings in perirenal urinomas. Delayed films after the administration of iv contrast usually demonstrate extravasation of urine that contains contrast into the urinoma with consequent opacification of the cyst-like structure (3). The precise site of the leak may be delineated, as in this case (1, 7). The wall of the urinoma enhances mildly with iv contrast because of the inflammation and neovascularity of the pseudocapsule (6). The differential diagnosis of urinoma includes hematoma and abscess. In general, hematoma can be distinguished from urinoma on CT scan by its higher attenuation coefficients (+20 to +80 vs -10 to +20), penetration through fascial planes, and absence of hydronephrosis (3). An abscess is often irregular and heterogeneous, can contain gas and traverse the tissue planes, and has a wall that may enhance to a greater degree than does the pseudocapsule of a urinoma (6). This is the first reported case of a urinoma that resembles a pancreatic pseudocyst on abdominal CT scan. This distinction would have particular clinical relevance following blunt abdominal trauma, which
Volume 11, 1992
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Sorgman, Langevin, and Banks
could lead either to traumatic pancreatitis with formation of a pseudocyst or to renal injury with formation of a urinoma. Both entities may be adjacent to the pancreatic body and tail, and the wall of both structures may enhance weakly with iv contrast. The distinction between pancreatic pseudocyst and urinoma can be made on CT scan with iv contrast if delayed films are obtained. If the cystic structure is a pseudocyst, there is no enharw~ment of the fluict If the structure is a urinoma, there is uniform enhancement of the fluid on delayed films, and the precise site of extravasation may be seen.
References 1 Mclnerney D, Jones A, Roylance J. Urinoma. Clin Radiol 1977; 28: 345-351. 2 Rose BS, Ragosin R, LaRoga JL, Drago JR. Pyelosinus extravasation and urinoma associated with malignancy: computed tomography demonstration. Urology 1988; 31: 349-353. 3 Healy ME, Teng SS, Mogg AA. Uriniferous pseudocyst: computed tomographic findings. Radiology 1984; 153: 757762. 4 Razzaboni G. Richerche sperimentali sulla Pseudoidnefrosi. Archivo Italiano di Chirurgia 1922; 6: 365. 5 Meyers MA. Uriniferous perirenal pseudocyst: new observations. Radiology 1975; 117: 539-545. 6 Lang EK, Glorioso L. ~I. Management of urinomas by percutaneous drainage procedures. Radial Clinics of North America 1986; 24: 551-559. 7 Mitty HA. CT for diagnosis and management of urinary extravasation. Am JRadiol 1980; 134: 497-501.
International Journal of Pancreatology
Volume 11, 1992
