Open Access

Lymphoepithelial cyst with sebaceous glands of the pancreas: a case report

Surgical Case Reports20162:98

DOI: 10.1186/s40792-016-0228-4

Received: 10 August 2016

Accepted: 13 September 2016

Published: 15 September 2016

Abstract

Background

Lymphoepithelial cyst (LEC) of the pancreas is a rare benign tumor. LEC with sebaceous glands of the pancreas is extremely rare, and its histogenesis remains unclear.

Case presentation

We present a 66-year-old man with an incidental finding of a cystic lesion at the neck of the pancreas. Pancreatic juice cytology results and elevated serum carbohydrate antigen 19-9 and Dupan-2 levels indicated that the cyst was a potential adenocarcinoma. Therefore, a pancreaticoduodenectomy was performed. Macroscopically, the tumor was a unilocular cyst with a thin transparent wall, filled with soft yellow material. Pathological findings showed that the cyst was lined with squamous epithelium, accompanied by dense lymphoid tissue with scattered germinal centers. There were no hair follicles, but sebaceous glands were present in the lymphoid tissue just beneath the squamous epithelium. Therefore, the histopathological diagnosis was an LEC with sebaceous glands of the pancreas. Furthermore, the squamous epithelium surrounding the cyst was pathologically continuous with the tubular structure, indicating that the tubular structure transitioned into the squamous epithelium.

Conclusions

We report an extremely rare case of LEC with sebaceous glands of the pancreas. Moreover, the pathological findings, which showed that the tubular structure transitioned into the squamous epithelium, suggested that this was squamous metaplasia. In order to investigate the histogenesis of LEC of the pancreas, the pathological findings must be evaluated.

Keywords

Lymphoepithelial cyst Sebaceous gland Histogenesis

Background

A lymphoepithelial cyst (LEC) is a lesion that most commonly appears on the lateral neck and the parotid gland. LEC of the pancreas is a stratified squamous-lined cyst filled with keratinous material and surrounded by dense lymphoid tissue. LEC of the pancreas is a rare lesion and its histogenesis remains unclear. In particular, LEC with sebaceous glands is extremely rare [1]; sebaceous glands in a non-skin organ are often found in ectodermal organs, but they are rarely found in endodermal organs such as the pancreas. We herein present a case of LEC with sebaceous glands of the pancreas, in which the tubular structure/squamous epithelium change was seen on the pathological examination.

Case presentation

A 66-year-old man was referred to our hospital for further evaluation of a cystic lesion in the pancreatic head that was detected on computed tomography (CT) of the abdomen. He had liver dysfunction due to hepatitis C infection and diabetes mellitus. He had no history of abdominal surgery, trauma, or pancreatitis. Laboratory findings showed that serum levels of amylase and lipase were within normal limits. Carcinoembryonic antigen and s-pancreatic-1 antigen levels were within normal limits, but carbohydrate antigen 19-9 (CA19-9) and Dupan-2 levels were elevated (CA19-9, 55 U/ml (normal level, <37 U/ml); Dupan-2, 410 U/ml [normal level, <150 U/ml]).

Abdominal contrast-enhanced CT showed a low-density mass, 20 mm in size, at the neck of the pancreas. The mass was clear and round, with uniform content and no septa. The mass appeared to be protruding from the neck of the pancreas (Fig. 1). Magnetic resonance imaging (MRI) showed a round mass in which the intensity was lower than the intensity of water on T2-weighted images. The tumor showed high intensity on diffusion-weighted images (Fig. 2). Endoscopic retrograde cholangiopancreatography showed no abnormality in the main pancreatic duct, and there was no evident continuity between the tumor and the main pancreatic duct (Fig. 3). The pancreatic juice contained high levels of mucin, and cytological examination showed large cell clusters with no nuclear atypia. These clusters showed high levels of proliferation, although the nuclei were relatively small (Fig. 4). The tumor was diagnosed as a suspected adenocarcinoma with a retention cyst, and a pancreaticoduodenectomy was performed.
Fig. 1

Abdominal contrast-enhanced computed tomography. Abdominal contrast-enhanced computed tomography showing a clear, round, low-density mass, 20 mm in size, protruding from the neck of the pancreas (arrows). a Axial view and b coronal view

Fig. 2

Magnetic resonance imaging of the abdomen. a T2-weighted image showing a clear, round, mass in which the intensity was lower than the intensity of water. b Diffusion-weighted image showing a high-intensity mass (arrowheads)

Fig. 3

Endoscopic retrograde cholangiopancreatography. Endoscopic retrograde cholangiopancreatography showing no abnormality in the main pancreatic duct

Fig. 4

Cytology of pancreatic juice. Cytology of pancreatic juice showing large cell clusters with small nuclei and strong proliferation, indicating a suspected adenocarcinoma

Macroscopically, the tumor was 20 mm in size. It consisted of a unilocular cyst with a thin transparent wall, filled with soft yellow material (Fig. 5). Pathological findings showed that the cyst was lined with squamous epithelium, accompanied by dense lymphoid tissue with scattered germinal centers (Fig. 6a). The squamous epithelium surrounding the cyst was continuous with the tubular structure, potentially representing the transition of the tubular structure into squamous epithelium (Fig. 6b). There were no hair follicles, but sebaceous glands were present in the lymphoid tissue just beneath the squamous epithelium (Fig. 6c). There was no evidence of dysplasia or malignancy. Immunostaining showed that the squamous epithelium expressed CA19-9 (Fig. 6d). The histopathological diagnosis was a benign lymphoepithelial cyst with sebaceous glands of the pancreas.
Fig. 5

Cross sections of the resected specimen. The tumor size was 20 mm in diameter and demonstrated a unilocular cyst with a thin transparent wall, filled with soft yellow material

Fig. 6

Pathological findings. a Cyst surrounded by squamous-lined epithelium, accompanied by dense lymphoid tissue with scattered germinal centers. Hematoxylin-eosin staining, original magnification ×40. b Tubular structure (arrows) continuous with the squamous epithelium (arrowheads). Hematoxylin-eosin staining, original magnification ×400. c Sebaceous glands present in the lymphoid tissue just beneath the squamous epithelium. Hematoxylin-eosin staining, original magnification ×200. d Immunohistochemistry showing for CA19-9-positive cells in the squamous epithelium

Although delayed gastric emptying occurred postoperatively, the patient was discharged on postoperative day 28. Eighteen months after surgery, there were no signs of recurrence or other lesions such as pancreatic cancer or intraductal papillary mucinous neoplasm on abdominal contrast-enhanced CT.

Discussion

We resected an LEC with sebaceous glands of the pancreas, which is extremely rare. In addition, the pathological findings revealed the histogenesis of the LEC. These findings showed squamous metaplasia that subsequently protruded from the pancreatic parenchyma into a peripancreatic lymph node.

The first description of a squamous-lined cyst of the pancreas, which was filled with keratinous material and surrounded by dense lymphoid tissue, was reported by Luchirath et al. in 1985 [2]. In 1987, Truong et al. proposed the term “LEC of the pancreas” [3]. Diane et al. reviewed 117 cases of LEC of the pancreas between 1987 and 2012: 78 % of the patients were men; serum CA19-9 levels were elevated in 50 % of cases; and LEC of the pancreas could be correctly diagnosed on fine-needle aspiration (FNA) biopsy in 21 % of cases [4]. LEC of the pancreas shows variable imaging findings because it has both liquid and solid components. MRI is useful for the diagnosis of cystic tumors; however, cysts with viscous fluid show low intensity on T2-weighted images and high intensity on diffusion-weighted images. It is very difficult to diagnose LEC correctly or to rule out malignancy on the basis of the preoperative imaging findings. Resection is unnecessary for benign non-neoplastic disease, including LEC. FNA can be used to make a preoperative pathological diagnosis; however, if the cyst is a malignant tumor, there is a risk of peritoneal seeding with FNA. Careful examination and informed consent are necessary before FNA of a cystic tumor.

In this case, the cyst was lined with stratified squamous epithelium with dense lymphoid tissue underneath. Furthermore, a sebaceous gland was embedded in the lymphoid tissue just beneath the squamous epithelium. These results suggested a potential dermoid cyst. However, we diagnosed the cyst as an LEC of the pancreas with sebaceous differentiation owing to the lack of hair follicles, fewer sebaceous glands, and the presence of dense lymphoid tissue. Only seven cases of LEC of the pancreas with sebaceous differentiation have been reported to date [1, 510].

The clinical features of the previously reported patients are summarized in Table 1. All these patients were middle-aged men. The median cyst size was 47.5 mm (range, 20–100 mm). The location and the loculation of the cysts varied. FNA was performed in four cases, but only one case was correctly diagnosed preoperatively. These results highlight the difficulties associated with preoperative diagnosis of LEC of the pancreas. Slightly elevated serum CA19-9 levels were present in four cases; CA19-9 levels were not determined in the other cases. This highlights another difficulty in the diagnosis, because elevated serum CA19-9 levels may lead to a false diagnosis of a malignant tumor.
Table 1

Clinical features of previously reported lymphoepithelial cysts with sebaceous glands of the pancreas

 

Author

Age (years)/sex

Symptom

Pancreatic location

Max. Size

Loculation

FNA

Serum CA19-9 (U/ml)

Preoperative diagnosis

1

Fitko [5]

60/male

Abdominal pain

Body

45 mm

Uni

Yes

N/A

A diagnosis could not be made

2

Koga [6]

62/male

None

Head

52 mm

Multi

No

N/A

Cystadenocarcinoma

3

Rino [7]

58/male

None

Head

50 mm

Multi

Yes

39

Epidermoid cyst

4

Fukukura [8]

70/male

Diarrhea

Tail

100 mm

Uni

No

N/A

Not described

5

Fujiwara [9]

60/male

None

Tail

40 mm

Uni

No

98

Mucinous cystic neoplasm

6

Hebert [10]

48/male

None

Body

50 mm

Uni

Yes

N/A

LEC with sebaceous differentiation

7

Nakamura [1]

67/male

None

Body

42 mm

Multi

Yes

69.2

Cystic neoplasm

8

Our case

66/male

None

Head

20 mm

Uni

No

55

CIS or IPMC

Abbreviations: FNA fine needle aspiration, CA19-9 serum carbohydrate antigen 19-9, N/A information not available, LEC lymphoepithelial cyst, CIS carcinoma in situ, IPMC intraductal papillary mucinous carcinoma

Sebaceous glands in a non-skin organ, i.e., ectopic sebaceous glands, are often found in ectodermal organs. However, ectopic sebaceous glands or neoplastic lesions with sebaceous glands rarely occur in the endodermal organs, such as the thyroglossal duct, larynx, esophagus, or thymus [11]. The pancreas is also an endodermal organ. Sebaceous gland differentiation at various sites may be due to the multipotentiality of the germinative cells of the squamous epithelium [5]; however, few details are available owing to the low number of reported cases.

The histogenesis of LEC of the pancreas remains unclear. Three theories have been proposed: (1) the lesion arises from a misplaced portion of the branchial cleft that fuses with pancreatic anlage during embryogenesis, (2) the lesion represents squamous metaplasia of an obstructed and dilated pancreatic duct that subsequently protrudes from the pancreatic parenchyma into a peripancreatic lymph node, and (3) the lesion arises from a benign epithelial inclusion or ectopic pancreas in a peripancreatic lymph node and subsequently encroaches into the pancreatic tissue [3]. The hypothesis that the lesion arises from a misplaced portion of the branchial cleft may suggest distinctive histologic features consistent with an anatomic relationship with the pancreas. However, this has not been confirmed by any embryologic evidence. Another hypothesis that the lesion arises from a benign epithelial inclusion or ectopic pancreas is likely to have arisen due to its similarity to the more common salivary lymphoepithelial cyst [12]. However, the ectopic pancreas in peripancreatic lymph nodes is extremely rare [13], and this hypothesis cannot account for the observed continuity with the pancreatic parenchyma. In the present case, the cyst was continuous with the pancreatic parenchyma, histopathologically. Furthermore, it was indicated that the cyst wall represented squamous metaplasia because the transition of the tubular structure into squamous epithelium was seen pathologically. Furthermore, CA19-9-positive cells were observed in the squamous epithelium on immunostaining. Therefore, it is likely that the histogenesis in this case may be considered squamous metaplasia of the glandular epithelium of the pancreas, which subsequently protruded from the pancreatic parenchyma into the peripancreatic lymphoid tissue.

Conclusions

Here, we report an extremely rare case of LEC with sebaceous glands of the pancreas. We believe that this is the first report to demonstrate the histogenesis of LEC of the pancreas in the pathological findings. To further investigate the histogenesis of LEC of the pancreas, it will be necessary to evaluate pathological findings in detail by accumulating additional cases.

Abbreviations

CA19-9: 

Carbohydrate antigen 19-9

CT: 

Computed tomography

FNA: 

Fine-needle aspiration biopsy

LEC: 

Lymphoepithelial cyst

MRI: 

Magnetic resonance imaging.

Declarations

Acknowledgements

The authors declare no financial or any other type of support.

Authors’ contributions

HM described and designed the manuscript. HS and MT revised the manuscript. MI carried out the pathological diagnosis. KM, HA, and SN carried out the surgery and postoperative management. All authors read and approved the final manuscript.

Competing interests

The authors declare that they have no competing interests.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and any accompanying images.

Ethics approval and consent to participate

Not applicable.

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors’ Affiliations

(1)
Department of Surgery, Shiga University of Medical Science
(2)
Department of Clinical Sciences and Laboratory Medicine, Kansai Medical University

References

  1. Nakamura T, Osaka Y, Ishikawa S, Sako H, Akamatsu N, Yamamoto Y, et al. Uncommon lymphoepithelial cyst with sebaceous glands of the pancreas. JOP. 2013;14:632–5.PubMedGoogle Scholar
  2. Luchirath H, Schriefers KH. A pancreatic cyst with features of a so-called branchiogenic cyst. Pathologe. 1985;6:217–9. Article in German.Google Scholar
  3. Truong LD, Rangdaeng S, Jordan Jr PH. Lymphoepithelial cyst of the pancreas. Am J Surg Pathol. 1987;11:899–903.View ArticlePubMedGoogle Scholar
  4. Mege D, Grégoire E, Barbier L, Del Grande J, Le Treut YP. Lymphoepithelial cyst of the pancreas: an analysis of 117 patients. Pancreas. 2014;43:987–95.View ArticlePubMedGoogle Scholar
  5. Fitko R, Kampmeier PA, Batti FH, Benjoya RA, Rao SM. Lymphoepithelial cyst of the pancreas with sebaceous differentiation. Int J Pancreatol. 1994;15:145–7.PubMedGoogle Scholar
  6. Koga H, Takayasu K, Mukai K, Muramatsu Y, Mizuguchi Y, Furukawa H, et al. CT of lymphoepithelial cysts of the pancreas. J Comput Assist Tomogr. 1995;19:221–4.View ArticlePubMedGoogle Scholar
  7. Rino Y, Morohoshi T, Funo K, Imada T, Yamamoto Y, Jojima T, et al. Lymphoepithelial cyst of the pancreas: a preoperatively diagnosed case based on an aspiration biopsy. Surg Today. 1995;25:1043–6.View ArticlePubMedGoogle Scholar
  8. Fukukura Y, Inoue H, Miyazono N, Kajiya Y, Fujiyoshi F, Yano T, et al. Lymphoepithelial cysts of the pancreas: demonstration of lipid component using CT and MRI. J Comput Assist Tomogr. 1998;22:311–33.View ArticlePubMedGoogle Scholar
  9. Fujiwara H, Kohno N, Nakaya S, Ishikawa Y. Lymphoepithelial cyst of the pancreas with sebaceous differentiation. J Gastroenterol. 2000;35:396–401.View ArticlePubMedGoogle Scholar
  10. Hébert-Magee S, Garvin D, Ahlawat S, Haddad N. Lymphoepithelial cyst of the pancreas with sebaceous differentiation: cytologic diagnosis by fine-needle aspiration. Diagn Cytopathol. 2009;37:937–9.View ArticlePubMedGoogle Scholar
  11. Wolff M, Rosai J, Wright DH. Sebaceous glands within the thymus: report of three cases. Hum Pathol. 1984;15:341–3.View ArticlePubMedGoogle Scholar
  12. Weidner N, Geisinger KR, Sterling RT, Miller TR, Benedict Yen TS. Benign lymphoepithelial cyst of the parotid gland: a histologic, cytologic and ultrastrucutural study. Am J Clin Pathol. 1986;85:395–401.View ArticlePubMedGoogle Scholar
  13. Murayama H, Kikuchi M, Imai T, Yamamoto Y, Iwata Y. A case of heterotopic pancreas in lymph node. Virchows Arch A Pathol Anat Histol. 1978;377:175–9.View ArticlePubMedGoogle Scholar

Copyright

© The Author(s). 2016