Gastric Duplication Cysts Expressing Carcinoembryonic Antigen Mimicking Cystic Pancreatic Neoplasms in Two Adults
By Johnston, Jeffrey Wheatley, Grayson H III; Sayed, Hosam F El; Marsh, William B; Ellison, E Christopher; Bloomston, Mark
Gastric duplication cysts in adults are very rare and usually found incidentally during evaluation for an unrelated ailment. When they are found in close proximity to the pancreas, they can be confused with cystic neoplasms of the pancreas, which are typically also asymptomatic yet more common. As part of the evaluation of cystic pancreatic lesions, cyst fluid analysis for carcinoembryonic antigen (CEA) is undertaken to determine malignant potential. Herein we present two cases of cystic lesions thought to arise from the pancreas found to have elevated preoperative cystic CEA levels. At operation, they were found to be gastric duplication cysts and were resected. We report the histologic findings and review of the current literature. DUPLICATION OF THE ALIMENTARY tract is a relatively rare congenital anomaly. It can affect any part of the entire gastrointestinal tract with the ileum being the most common site.1 Duplication cysts of the stomach represent four per cent of all alimentary tract duplications.2 Approximately 67 per cent of gastric duplication cysts (GDC) are identified within the first year of life.2 Symptoms usually include abdominal pain, vomiting, weight loss, and hematemesis. Abdominal tenderness and an epigastric mass might be present on physical examination.
Duplication cysts in adults are generally asymptomatic and are commonly incidental findings at gastrointestinal endoscopy or barium contrast radiography. Complications that arise with GDC include gastric outlet obstruction, infection, peptic ulcer development within the cyst, and carcinoma, though carcinoma is rare (five cases reported in literature).3 When in close proximity to the pancreas, GDC can be confused with a primary cystic pancreatic neoplasm. We report two adult patients with gastric duplication cysts initially diagnosed as cystic lesions of the pancreas associated with elevated carcinoembryonic antigen (CEA) in the cyst fluid and positive CEA staining of the cyst lining.
A previously healthy 24-year-old man presented to his family physician with a 3- to 4-week history of intermittent midepigastric abdominal pain. He also complained of lethargy with occasional nausea and loose stools. His past medical history was significant only for an episode of blunt trauma from a sledding accident 8 years prior with no associated injuries. In addition, he consumed 12 to 24 beers each weekend. His physical examination was unremarkable, and there was neither abdominal tenderness nor a palpable mass.
His initial workup consisted of a right upper quadrant ultrasound, which demonstrated two cystic structures located within the tail of the pancreas. The gallbladder and biliary system were unremarkable. Computed tomography (CT) of the abdomen confirmed the presence of a 4 x 5 cm cyst in the tail of the pancreas, which appeared separate from the stomach (Fig. 1). Endoscopic retrograde cholangiopancreatography showed normal common bile and pancreatic ducts without communication with the cyst. Upper endoscopy was also unremarkable. Laboratory values, including complete blood count, serum chemistries, liver function tests, amylase, lipase, serum gastrin, CEA, and carbohydrate antigen (CA) 19-9, were all within normal limits. Preoperative cyst aspiration was undertaken and returned a CEA level of 555.7 ng/mL (normal < 4.5 ng/mL), amylase 33 U/L (normal < 140 U/L), and lipase 11 U/L (normal < 49 U/L). Cytology was acellular.
The most likely clinical diagnosis was cystic tumor of the distal pancreas and the patient was taken to the operating room for resection. At the time of exploration, the tail of the pancreas appeared to be normal, without evidence of the cystic structures. However, a large, bilobed cystic structure was located in the lesser sac posterior to the stomach and superior to the tail of the pancreas. The cyst measured 10 x 4 x 2 cm, did not seem to communicate with the stomach or pancreas, and seemed to be tethered only by a short mesentery containing a short gastric artery. Within the cyst was a milky, mucinous fluid. The lesion was felt to be a gastric duplication cyst and it was completely excised. A thorough exploration of the patient’s abdomen was otherwise unremarkable. The patient recovered uneventfully and was discharged home on postoperative day 6. In follow-up, he had complete resolution of his symptoms.
FIG. 1. Computed tomography scan of 4 x 5 cm cystic lesion in the tail of the pancreas.
On pathological examination, the cyst measured 6.0 x 5.5 x 2.0 cm, with a wall thickness of 0.2 to 0.3 cm. The cyst wall was smooth with no masses or papillae. Microscopically, the cyst wall was composed of mucosa, submucosa, and muscularis propria. Focally, the cyst was lined by gastric mucosa (Fig. 2A) with rare parietal cells, focally dilated foveolar glands, and chronic inflammation. Focally, the cyst lining was a single layer of columnar to mucinous epithelium. In much of the cyst, the mucosa was ulcerated and showed inflamed granulation tissue, macrophages, fibrosis, and lymphoid aggregates. Immunostain for polyclonal CEA was positive in the surface epithelium of the gastric mucosa and single-layered mucinous epithelium (Fig. 2B).
FIG. 2. Histological examination of resected gastric duplication cysts. (A) Hematoxylin and eosin stain (250 x ) of cyst lining in patient 1, showing gastric mucosa. (B) Immunohistochemistry for CEA is positive in the cyst lining. (C) Hematoxylin and eosin (250 x ) of cyst lining in patient 2, showing gastric mucosa.
A healthy 49-year-old woman was referred from an outside hospital for further evaluation of an asymptomatic cystic lesion in the lesser sac. The patient had no significant past medical or surgical history. She had no history of abdominal trauma and no history suggestive of acute or chronic pancreatitis. She had no history of any abdominal or gastrointestinal complaints. She was not a smoker and had no history of alcohol intake. On physical examination, she had no palpable masses and no tenderness. Her complete blood count, routine chemistries, liver enzymes, amylase, and lipase were all normal. She also had normal CEA and CA 19-9. The patient was referred because CT scan and magnetic resonance imaging of the abdomen and pelvis showed a 3 x 4 cm single cystic lesion that was between the greater curve of the stomach, the hilum of the spleen, and the tail of the pancreas without any other abnormal findings in the scans.
The cystic lesion was suggestive of a cystic neoplasm of the pancreatic tail versus the less common gastric duplication or splenic cyst. Fluid analysis showed a CEA of 2381 ng/mL and CA 19-9 of 79,069 U/mL. At the time of operation, the lesion was found to be arising from the greater curve of the stomach, separate from the pancreas and spleen. The lesion was cystic, oval, measuring 4 x 6 x 3 cm, and seemed somewhat pedunculated. The lesion was dissected from the wall of the stomach and did not communicate with the lumen of the stomach, though it did share the same outer muscle layer. The cyst contained clear, mucinous fluid. The rest of abdominal exploration was essentially unremarkable. The patient had an uneventful recovery and was discharged home on postoperative day 3.
On pathological examination, the cyst was 4.8 x 3.4 x 2.2 cm with a wall thickness of 0.2 cm and contained clear mucoid material. The cyst wall was smooth and tan/pink in color. Microscopically, the cyst wall was composed of mucosa, submucosa, and muscularis propria. The mucosa lining the cyst varied from gastric with focal parietal cells and chronic inflammation (Fig. 2C) to cuboidal/columnar. Immunostains showed that the lining was positive for polyclonal CEA and negative for gastrin.
Alimentary tract duplications are congenital anomalies, which may occur anywhere along the gastrointestinal tract. Ileal duplications are most common, followed by those of the esophagus, colon, jejunum, and stomach. Nearly two-thirds of gastric duplications occur in women. Greater than 80 per cent of gastric duplications are cystic and do not communicate with the lumen of the stomach or alimentary tract.1 The remainder are tubular duplications with some communication. The majority of GDC occur on the greater curvature of the stomach.4
Rowling5 established several criteria for defining gastric duplication: 1) the cyst wall must be contiguous with the stomach wall, 2) the cyst is surrounded by smooth muscle, which is contiguous with that of the stomach, and 3) the cyst is lined by gastric epithelium. Gastric duplications are typically symptomatic during childhood with 67 per cent diagnosed within the first year of life and less than 25 per cent discovered after age 12.4, 6 Additional anomalies such as esophageal duplication, vertebral abnormalities, aberrant pancreas, and duodenal duplication are found in 50 per cent of patients with gastric duplication.1 When identified in the pediatric population, duplications are always benign.4
Gastric duplications present a difficulty in diagnosing the adult population. The symptoms are frequently nonspecific with intermittent abdominal pain being the most common. Imaging modalities such as CT are frequently of insufficient resolution to determine the nature of the cystic structure. Because the majority of duplications are noncommunicating, barium studies and upper endoscopy are often nondiagnostic, though both modalities may disclose a filling defect, particularly in the antrum of the stomach.7- 8 Similarly, endoscopic retrograde cholangiopancreatography is usually normal, except in the rare case that the duplication communicates with the pancreatic duct.8 The most common method of definitive diagnosis is by exploratory laparotomy.9 Because of the rarity of adult gastric duplications, it is difficult to outline with certainty their natural history. As with native gastric mucosa, the cyst lining may ulcerate. In a noncommunicating cyst, increased fluid production may result in pressure-induced necrosis of the mucosa.4 Both of these scenarios may lead to bleeding into the cyst or perforation into the peritoneum.10, 11 Communicating cysts may connect with the pancreatic ducts and cause recurrent pancreatitis.12 Up to 10 per cent of gastric duplications may contain ectopic pancreatic tissue which may be prone to pancreatitis.9
Duplication cysts also have the potential for neoplastic transformation.4 Of the 11 reported cases of malignancy arising within duplication cysts, eight have been adenocarcinoma. Five of the carcinomas have originated from gastric duplication.13 Adenomyoma arising from a gastric duplication has also been reported.12 Malignancies arising from duplication cysts are likely to present at more advanced stages because of their unusual symptoms and difficulty of diagnosis.4
Surgical resection is the mainstay of therapy with the goal of complete cyst excision. Drainage and marsupialization of the cyst have been suggested. However, marsupialization into the stomach exposes the unprotected mucosa to gastric contents with the risk of ulceration. Drainage procedures, such as cystjejunostomy, may be complicated by stenosis of the anastomosis or blind loop syndrome and are, therefore, discouraged.14 Furthermore, leaving the cyst in place is ill-advised given the potential for malignant transformation.
Gastric duplications are exceedingly rare in adults but can mimic cystic neoplasms of the pancreas. To our knowledge, this report represents two of three known cases of gastric duplication where radiographic and cyst fluid analysis were suggestive of mucinous cystic neoplasms of the pancreas, the third being recently reported in a 29-year-old woman.15 All three of these cases demonstrated CEA staining along the cyst lining and in the cyst fluid, similar to those seen in duodenal and ileal duplications.1, 16 The presence of CEA within the cyst aspirate and along the cyst lining is of uncertain significance. This may represent a form of mucosal sequestration of embryonic tissue, with the high level of CEA reflecting its high level in the circulation during embryogenesis of the cyst. Increased intracystic CEA and CA 19-9 may be a precursor to neoplastic changes or demonstrate a malignant potential. Given the rarity of GDC, such an implication would be difficult to substantiate.
The presence of increased CEA in gastric duplication cysts can confound the preoperative work-up of a pancreatic cystic lesion where cyst aspiration is often used to guide therapy. As a gastric duplication can be mistaken for a cystic lesion of the pancreas, preoperative aspiration demonstrating elevated CEA within the cyst may suggest a premalignant or malignant lesion. This finding suggests that GDC should be in the differential diagnosis of “pancreatic cysts” with increased CEA in the cyst fluid if the lesion is in close proximity to the stomach.
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JEFFREY JOHNSTON, B.S.,* GRAYSON H. WHEATLEY III, M.D.,* HOSAM F. EL SAYED, M.D.,*
WILLIAM B. MARSH, M.D.,[dagger] E. CHRISTOPHER ELLISON, M.D.,* MARK BLOOMSTON, M.D.*
From the Departments of *Surgery and [dagger]Pathology, Ohio State University Medical Center, Columbus, Ohio
Address correspondence and reprint requests to Mark Bloomston, M.D., Assistant Professor of Surgery, N924 Doan Hall, 410 West Tenth Avenue, Columbus, OH 43210. E-mail: Mark.Bloomston@osumc.edu.
Copyright Southeastern Surgical Congress Jan 2008
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