Lymphoepithelial cyst of the pancreas: serum markers do not help

An Unusual Suspect: Lymphoepithelial Cyst of the Pancreas

Lymphoepithelial cysts (LECs) of the pancreas are benign, rare pancreatic cysts that are found predominantly in men. These cysts can present as a diagnostic conundrum given their rarity and difficulty of distinguishing these cysts from those with malignant potential. We present an incidental case of a LEC in a middle-aged man.

Lymphoepithelial cyst of the pancreas: an analysis of 117 patients

OBJECTIVES

Lymphoepithelial cyst (LEC) of the pancreas is an unusual and benign cystic tumor. Accurate preoperative diagnosis is difficult; hence, most of pancreatic LECs are resected. The aim was to describe clinicopathological features of pancreatic LEC to guide appropriate management.

METHODS

We retrospectively collected data about LEC patients treated in our department between 1987 and 2012 and added cases from review of the literature during the same period.

RESULTS

One hundred seventeen cases (3 from our institution and 114 from literature review) were identified. Most patients were men (78%). The discovery was generally fortuitous. Serum CA19-9 was elevated in half of the cases. No specific radiological feature was identified. Fine needle aspiration and cytologic analysis allowed a correct preoperative diagnosis in 21% of the patients, showing presence of squamous cells, lymphocytes, and keratinous debris. Half of them were treated conservatively, whereas other patients underwent surgery. Neither malignant transformation nor recurrence after resection was observed.

CONCLUSIONS

The LEC of the pancreas is a rare benign tumor that could be treated conservatively. Fine needle aspiration is the only tool that can achieve a diagnosis without resection. If no certain diagnosis can be made, surgery is warranted to rule out a malignant differential diagnosis.

Lymphoepithelial cyst of the pancreas

Cystic lesions of the pancreas can be divided into true cysts, pseudocysts, and cystic neoplasms. Lymphoepithelial cysts (LECs) are a type of true cyst that can mimic pseudocysts and cystic neoplasms. LECs are rare lesions; fewer than 90 cases have been reported in the English language literature. The case of a 60-year-old man with an LEC of the pancreas is reported. He was admitted with upper abdominal discomfort. Computed tomography showed a 64 × 39 mm cystic mass in the retroperitoneum behind the duodenum and inferior caval vein. Magnetic resonance imaging revealed a right-sided mass on T1-weighted imaging, with a clear boundary between the mass and its surroundings, except for the pancreas. The mass had an inhomogeneous intensity on T2-weighted imaging. Within the mass, small floating nodules with low intensity were seen. Endoscopic ultrasound showed many high-echoic nodules and smaller grains scattered everywhere in the mass. Fine needle aspiration and cytologic examination were performed. Characteristic chylaceous fluid was obtained in which anucleate squamous cells were found. There were also a few atypical large cells with irregularly shaped marked nucleoli and degenerative cytoplasm. Cytologic diagnosis was suspicious for malignancy. The lesion was diagnosed as a retroperitoneal cyst, probably of pancreatic origin. Since a neoplastic lesion could not be ruled out, surgery was performed. The lesion was palpable on the dorsal side of the second portion of the duodenum. The mass was completely resected. Macroscopically, the lesion was a multilocular cyst with a thin septal wall. The cyst was filled with cottage cheese-like substance. Microscopically, the cyst wall was composed of stratified squamous epithelium and dense subepithelial lymphatic tissue with developed lymph follicles. The epithelial cells had no atypia. The histopathologic diagnosis was LEC of the pancreas. The patient's postoperative course was good.

Pancreatic lymphoepithelial cysts express CEA and can contain mucous cells: potential pitfalls in the preoperative diagnosis

Pancreatic lymphoepithelial cysts are rare benign cysts that cannot be reliably differentiated from neoplastic mucinous cysts preoperatively. Although elevated cyst fluid carcinoembryonic antigen (CEA) levels support a diagnosis of a mucinous cyst, the finding of increased CEA levels in lymphoepithelial cysts prompted this study. Nine resected lymphoepithelial cysts were examined for expression of CEA, carbohydrate antigen (CA) 19-9, CK7, p63, PAS-D and a panel of mucins. The pathology data were correlated with clinical information, including serum, cyst fluid and imaging studies. By computed tomography scan, although most lymphoepithelial cysts appeared cystic, 23% were described as masses. The endoscopic ultrasound findings were variable, but the lymphoepithelial cysts tended to be hypoechoic cystic lesions or masses. On cytology, 44% of the cysts had squamous cells, 67% had glandular cells and 56% had atypical cells. The cysts were resected because of size ≥3 cm (89%), symptoms (44%) and/or elevated cyst fluid CEA levels (33%). The cyst fluid CEA levels in the three cysts tested were >450 ng/ml. Histopathologically, all cysts were lined by mature, stratified squamous-type cells and produced keratin. Mucous cells were present in 78% of the cysts. The immunohistochemical profile of the squamous lining was CK7+, p63+, MUC1+, MUC4+, MUC2-, MUC5AC- and MUC6-. Even though lymphoepithelial cysts are lined by squamous-type epithelium, all our resected lymphoepithelial cysts expressed CEA and/or CA19-9, many contained mucous cells, and three exhibited markedly elevated cyst fluid CEA levels. Although cyst fluid CEA levels >200 ng/ml support the diagnosis of mucinous neoplasms, this study emphasizes the need for clinicians and pathologists to recognize that lymphoepithelial cysts can mimic neoplastic mucinous cysts clinically, radiographically and on cyst fluid CEA analysis.

Lymphoepithelial cysts of the pancreas: a report of 12 cases and a review of the literature

Lymphoepithelial cyst (LEC) of the pancreas is a rare lesion of undetermined pathogenesis that had been documented almost exclusively in males. The literature on this entity is limited to reports of single or small numbers of cases. Here is presented a clinicopathologic analysis of 12 patients with LEC, 4 of whom were female. The mean age of the patients was 56 years. Four patients presented with abdominal pain and nausea, but in two patients, the cysts were detected incidentally. Only one patient had a history of chronic pancreatitis, and another had a family member with pancreatic cancer. In one patient, a clinical diagnosis of pseudocyst was rendered, and the remaining patients were clinically thought to have cystic neoplasms. None of the patients had any identifiable immunosuppression, HIV positivity, autoimmune disorder (such as Sjogren syndrome) or lymphoma. Seven cysts were located in the head of the pancreas, and 5 were in the tail. The mean size was 4.8 cm (range, 1.2-17 cm). Five LECs were multilocular, three were unilocular; in others, the number of loculi was not recorded. All were "macrocystic" lesions. Two patients had two separate lesions, both in the tail of the pancreas. Histologically, all cases were characterized by cysts, some containing keratin, and lined by mature stratified squamous epithelium surrounded by dense lymphoid tissue, often with prominent follicles. In some areas, the lining epithelium had more cuboidal, flattened, or transitional appearance. Mucinous goblet-like cells were seen in one case. Acute inflammation was not seen. Four cases contained solid lymphoepithelial islands, a feature not previously described in LECs. No squamous metaplasia was identified in the uninvolved pancreatic tissue and no epithelial elements were identified in peripancreatic lymph nodes. In summary, LEC of the pancreas is a rare but distinctive lesion that may be seen in the tail of the organ where most cystic pancreatic neoplasms are encountered. In contrast to the impression from the literature, LECs may also develop in females and, therefore, should be considered in the clinical differential diagnosis of mucinous cystic neoplasms that affect a similar age group. LECs are not associated with the clinical syndromes that are seen with their analogues in the salivary glands.