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Lymphoepithelial cyst of the pancreas
Lymphoepithelial cyst of the pancreas Eric T. Castaldo, MD,a Jennifer R. Stumph, MD,b and Nipun Merchant, MD,a Nashville, Tenn
From the Department of Surgery,a Division of Surgical Oncology, and the Department of Pathology,b Vanderbilt University Medical Center
A 37-YEAR-OLD MAN with a past medical history of insulin-dependent diabetes mellitus and gastroesophageal reflux disease presented with epigastric pain after meals, early satiety, and a 7-pound weight loss over 3 weeks. He had no history of pancreatitis. Physical examination revealed a thin, African American male in no apparent distress. He had a nontender abdomen with no palpable masses. A right upper quadrant ultrasonography was obtained and revealed a solid/cystic mass in the head of the pancreas. A computed tomographic (CT) scan was performed and revealed a 3.4-cm mass with internal septations and papillary projections in the head of the pancreas. The mass butted the vena cava and compressed the right renal vein and duodenum. In addition, the stomach was dilated, indicating a component of gastric outlet obstruction (Fig 1). Laboratory evaluation revealed a serum carbohydrate antigen (CA) 19-9 of 14 U/mL (reference range, <38 U/mL). The only abnormality of his liver function tests was a lactate dehydrogenase of 97 U/L (reference range, 135-225 U/L). Given the concerns of a possible intraductal papillary mucinous neoplasm or a pancreatic cystadenocarcinoma, in combination with the patient’s weight loss and early gastric outlet obstruction symptoms, we made the decision to operate without obtaining an endoscopic ultrasonography or tissue diagnosis. A pylorus-preserving pancreaticoduodenectomy was performed. The patient had an uneventful hospital course and was discharged home on postoperative day 6. Accepted for publication October 3, 2005. Reprint requests: Eric T. Castaldo, MD, 801 Oxford House, Vanderbilt University, Nashville, TN 37232-4753. E-mail: eric. [email protected]. Surgery 2006;140:476-8. 0039-6060/$ - see front matter Ó 2006 Mosby, Inc. All rights reserved. doi:10.1016/j.surg.2005.10.006
476 SURGERY
Gross inspection of the tumor revealed a 4.5 cm 3 3.8 cm 3 3.6 cm cyst located in the posterior aspect of the pancreatic head (Fig 2). It was thin-walled and filled with white, pasty material. Microscopically, the lesion demonstrated a mature keratinizing squamous epithelium lining a cyst wall, with abundant keratinaceous debris filling the cyst lumen. The tissue underlying the cyst was populated with lymphoid cells. On the basis of these findings, the tumor was diagnosed as a lymphoepithelial cyst (LEC) of the pancreas.
DISCUSSION Lymphoepithelial cysts of the pancreas are rare, benign lesions that may mimic pancreatic pseudocysts or cystic neoplasms. Only 66 previous descriptions have been published in the English literature to date. Despite their infrequency, LECs of the pancreas have a distinct histologic appearance. They are true cysts of the pancreas and are lined by keratinized, stratified squamous epithelium without atypia. The cysts are closely approximated to a well-defined zone of lymphoid tissue, with germinal centers and a fibrous wall.1 In addition, it should be noted that the teratoid elements of the epithelium, such as skin appendages or mesenchymal tissue, are lacking. LECs have been described in the parotid gland, submandibular glands, lung, thyroid, intrathoracic region, and the cervical region. The natural history of LECs of the pancreas is largely unknown; however, the prognosis is quite good. There has never been a report of local recurrence after operative resection. In addition, LEC of the pancreas that degenerated into a malignancy or death has never been reported. This finding correlates to LECs found elsewhere in the body where recurrence after operative resection and/or transformation into malignancy are rare. However, there has been one case report of a mediastinal LEC associated with an adenocarcinoma, which demonstrated a transition between benign epithelial cells and neoplastic cells.2
Surgery Volume 140, Number 3
Castaldo, Stumph, and Merchant 477
Fig 1. CT scan demonstrating intracystic papillary projections and the relationship of the neoplasm to surrounding vasculature. Arrows denote papillary projections. IVC, Inferior vena cava; SMA, superior mesenteric artery; SMV, superior mesenteric vein.
If symptomatic, patients with a LEC of the pancreas can present with complaints such as pain or early satiety. The CT scan usually shows features of a low-attenuation mass with a cystic component, a thin enhancing rim, and/or multilocular lesions and focal wall calcification.3 Preoperative cytopathologic diagnosis is difficult. Fine-needle aspiration has been described.1,4 In these cases, cytopathologic examination revealed features that can be shared with other pathologic lesions of the pancreas. The main differentiating feature is the presence of a lymphoid component
in a LEC of the pancreas that is most apparent on histologic examination. Preoperative laboratory evaluation also can make proper diagnosis difficult. There appears to be no association with CA 19-9. Biochemical studies of cyst fluid for CA 19-9, CA 125, amylase, and carcinogenic embryonic antigen have been evaluated and also lead to conflicting results. In conclusion, if LEC is diagnosed before potential operative intervention, observation of the lesion to avoid unnecessary radical surgical procedures has been suggested. However, if the diagnosis is
478 Castaldo, Stumph, and Merchant
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uncertain or malignancy is suspected, operative resection should be performed.
REFERENCES
Fig 2. Bivalved, gross tumor specimen demonstrating a cystic structure of the head of the pancreas filled with keratinaceous debris. DU, duodenum; LEC, lymphoepithelial cyst; PD, pancreatic duct.
1. Mandavilli SR, Port J, Ali SZ. Lymphoepithelial cyst of the pancreas: Cytomorphology and differential diagnosis on fine-needle aspiration (FNA). Diagn Cytopathol 1999;20: 371-4. 2. Ishimaru Y, Shibata Y, Ohkawara S, et al. Lymphoepithelial cystic lesion related to adenocarcinoma of the mediastinum. Am J Clin Pathol 1989;92:808-13. 3. Kim YH, Auh YH, Kim KW, et al. Lymphoepithelial cysts of the pancreas: CT and sonographic findings. Abdom Imag 1998;23:185-7. 4. Liu J, Shin HJ, Rubenchik I, et al. Cytologic features of lymphoepithelial cyst of the pancreas: Two preoperatively diagnosed cases based on fine-needle aspiration. Diagn Cytopathol 1999;21:346-50.
From the Department of Surgery,a Division of Surgical Oncology, and the Department of Pathology,b Vanderbilt University Medical Center
A 37-YEAR-OLD MAN with a past medical history of insulin-dependent diabetes mellitus and gastroesophageal reflux disease presented with epigastric pain after meals, early satiety, and a 7-pound weight loss over 3 weeks. He had no history of pancreatitis. Physical examination revealed a thin, African American male in no apparent distress. He had a nontender abdomen with no palpable masses. A right upper quadrant ultrasonography was obtained and revealed a solid/cystic mass in the head of the pancreas. A computed tomographic (CT) scan was performed and revealed a 3.4-cm mass with internal septations and papillary projections in the head of the pancreas. The mass butted the vena cava and compressed the right renal vein and duodenum. In addition, the stomach was dilated, indicating a component of gastric outlet obstruction (Fig 1). Laboratory evaluation revealed a serum carbohydrate antigen (CA) 19-9 of 14 U/mL (reference range, <38 U/mL). The only abnormality of his liver function tests was a lactate dehydrogenase of 97 U/L (reference range, 135-225 U/L). Given the concerns of a possible intraductal papillary mucinous neoplasm or a pancreatic cystadenocarcinoma, in combination with the patient’s weight loss and early gastric outlet obstruction symptoms, we made the decision to operate without obtaining an endoscopic ultrasonography or tissue diagnosis. A pylorus-preserving pancreaticoduodenectomy was performed. The patient had an uneventful hospital course and was discharged home on postoperative day 6. Accepted for publication October 3, 2005. Reprint requests: Eric T. Castaldo, MD, 801 Oxford House, Vanderbilt University, Nashville, TN 37232-4753. E-mail: eric. [email protected]. Surgery 2006;140:476-8. 0039-6060/$ - see front matter Ó 2006 Mosby, Inc. All rights reserved. doi:10.1016/j.surg.2005.10.006
476 SURGERY
Gross inspection of the tumor revealed a 4.5 cm 3 3.8 cm 3 3.6 cm cyst located in the posterior aspect of the pancreatic head (Fig 2). It was thin-walled and filled with white, pasty material. Microscopically, the lesion demonstrated a mature keratinizing squamous epithelium lining a cyst wall, with abundant keratinaceous debris filling the cyst lumen. The tissue underlying the cyst was populated with lymphoid cells. On the basis of these findings, the tumor was diagnosed as a lymphoepithelial cyst (LEC) of the pancreas.
DISCUSSION Lymphoepithelial cysts of the pancreas are rare, benign lesions that may mimic pancreatic pseudocysts or cystic neoplasms. Only 66 previous descriptions have been published in the English literature to date. Despite their infrequency, LECs of the pancreas have a distinct histologic appearance. They are true cysts of the pancreas and are lined by keratinized, stratified squamous epithelium without atypia. The cysts are closely approximated to a well-defined zone of lymphoid tissue, with germinal centers and a fibrous wall.1 In addition, it should be noted that the teratoid elements of the epithelium, such as skin appendages or mesenchymal tissue, are lacking. LECs have been described in the parotid gland, submandibular glands, lung, thyroid, intrathoracic region, and the cervical region. The natural history of LECs of the pancreas is largely unknown; however, the prognosis is quite good. There has never been a report of local recurrence after operative resection. In addition, LEC of the pancreas that degenerated into a malignancy or death has never been reported. This finding correlates to LECs found elsewhere in the body where recurrence after operative resection and/or transformation into malignancy are rare. However, there has been one case report of a mediastinal LEC associated with an adenocarcinoma, which demonstrated a transition between benign epithelial cells and neoplastic cells.2
Surgery Volume 140, Number 3
Castaldo, Stumph, and Merchant 477
Fig 1. CT scan demonstrating intracystic papillary projections and the relationship of the neoplasm to surrounding vasculature. Arrows denote papillary projections. IVC, Inferior vena cava; SMA, superior mesenteric artery; SMV, superior mesenteric vein.
If symptomatic, patients with a LEC of the pancreas can present with complaints such as pain or early satiety. The CT scan usually shows features of a low-attenuation mass with a cystic component, a thin enhancing rim, and/or multilocular lesions and focal wall calcification.3 Preoperative cytopathologic diagnosis is difficult. Fine-needle aspiration has been described.1,4 In these cases, cytopathologic examination revealed features that can be shared with other pathologic lesions of the pancreas. The main differentiating feature is the presence of a lymphoid component
in a LEC of the pancreas that is most apparent on histologic examination. Preoperative laboratory evaluation also can make proper diagnosis difficult. There appears to be no association with CA 19-9. Biochemical studies of cyst fluid for CA 19-9, CA 125, amylase, and carcinogenic embryonic antigen have been evaluated and also lead to conflicting results. In conclusion, if LEC is diagnosed before potential operative intervention, observation of the lesion to avoid unnecessary radical surgical procedures has been suggested. However, if the diagnosis is
478 Castaldo, Stumph, and Merchant
Surgery September 2006
uncertain or malignancy is suspected, operative resection should be performed.
REFERENCES
Fig 2. Bivalved, gross tumor specimen demonstrating a cystic structure of the head of the pancreas filled with keratinaceous debris. DU, duodenum; LEC, lymphoepithelial cyst; PD, pancreatic duct.
1. Mandavilli SR, Port J, Ali SZ. Lymphoepithelial cyst of the pancreas: Cytomorphology and differential diagnosis on fine-needle aspiration (FNA). Diagn Cytopathol 1999;20: 371-4. 2. Ishimaru Y, Shibata Y, Ohkawara S, et al. Lymphoepithelial cystic lesion related to adenocarcinoma of the mediastinum. Am J Clin Pathol 1989;92:808-13. 3. Kim YH, Auh YH, Kim KW, et al. Lymphoepithelial cysts of the pancreas: CT and sonographic findings. Abdom Imag 1998;23:185-7. 4. Liu J, Shin HJ, Rubenchik I, et al. Cytologic features of lymphoepithelial cyst of the pancreas: Two preoperatively diagnosed cases based on fine-needle aspiration. Diagn Cytopathol 1999;21:346-50.