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Exophytic lymphoepithelial cyst of the pancreas Young Mi Ku a, Su Lim Lee a, Kee Hwan Kim b, Kyung-Jin Seo c,∗ a
Department of Radiology, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 271 Cheonbo-ro, Uijeongbu 480-717, Republic of Korea b Department of Surgery, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 271 Cheonbo-ro, Uijeongbu 480-717, Republic of Korea c Department of Hospital Pathology, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 271 Cheonbo-ro, Uijeongbu 480-717, Republic of Korea
A 50-year-old man was referred to our institute with a 1month history of epigastric and back pain. Computed tomography detected a bi-locular low attenuating lesion extending from the head of the pancreas (Fig. 1A, arrows) showing the ‘‘beak sign’’ (Fig. 1B, arrow), which can be defined as two lines with an acute angle traced by a mass outline and the adjacent organ (in this case, the pancreas), forming a beak shape. An oval, exophytic pancreatic lesion showed high signal intensity (SI) and some low-SI foci within the lesion on contrastenhanced T1-weighted magnetic resonance (MR) images (Fig. 1C, arrowheads). T1-weighted MR images revealed thick marginal wall enhancement (Fig. 1D, arrow). The differential diagnosis included a mucinous cystic neoplasm of the pancreas and an epidermoid cyst. As a neoplastic lesion could not be ruled out, surgical treatment was performed. The resected pancreas exhibited an exophytic, bi-locular cyst, measuring 5 × 4.5 cm (Fig. 2A). After making an incision, the cyst was observed to be filled with yellow greasy substance. The lesion adhered to the head of the pancreas (Figs. 2A and 2B), and most portions of the cyst apparently
∗
Corresponding author. E-mail address: [email protected] (K.-J. Seo).
protruded outside the pancreas. Microscopically, most of the cyst wall was lined by stratified squamous epithelium and was focally covered by flat cuboidal epithelium (Fig. 2C). The subepithelial layer consisted of a thick collagen bundle and lymphoid tissue (Fig. 2C). A few foci of extraluminal leakage of keratin material (Fig. 2D, left, black arrows) with prominent keratin granulomas (Fig. 2D, right) were also detected. Based on those pathological findings, the lesion was diagnosed as an exophytic lymphoepithelial cyst (LEC) of the pancreas. An LEC, very rare true cyst of the pancreas that was first described by Luchtrath and Schriefers in 1985 [1], is a unior multi-locular cystic lesion lined with squamous epithelium and surrounded by non-neoplastic lymphoid elements [2]. An LEC can be an intrapancreatic or protruding mass from the pancreatic parenchyma [3]. An LEC with an exophytic growth mimics an extra-pancreatic mass such as a pseudocyst, epidermoid cyst, or mucinous neoplasm [3]. One report stated that such lesions are commonly extrapancreatic in location [2]. The key histopathologic findings of LECs are cyst walls being lined with keratinizing epithelium and subepithelial dense lymphoid tissue admixed with germinal centers [3]. The main pathological differentials include dermoid cysts (DCs) and epidermoid cysts in intrapancreatic accessory spleens (ECISs). The presence of splenic red pulp
http://dx.doi.org/10.1016/j.clinre.2014.09.004 2210-7401/© 2014 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Ku YM, et al. Exophytic lymphoepithelial cyst of the pancreas. Clin Res Hepatol Gastroenterol (2015), http://dx.doi.org/10.1016/j.clinre.2014.09.004
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Figure 1 (A) Axial computed tomography image showing a bi-locular low attenuating mass (arrows) extending from the head of the pancreas. (B) Coronal image showing the so-called ‘‘beak sign’’ (arrow) adjacent to the lesion. (C) An oval exophytic pancreatic lesion (arrows) with high signal intensity and a few low signal intensity foci within it (arrowheads) on T2-weighted magnetic resonance (MR) image. (D) Contrast-enhanced T1-weighted MR image revealing thick lesion wall enhancement (arrow). No evidence of remarkable upstream pancreatic duct dilatation is visible. (St: stomach; Pn: pancreas).
Figure 2 (A) A photograph of the resected head of the pancreas showing a bi-locular cystic mass, measuring 5 × 4.5 cm. The cyst is filled with a greasy yellow substance. Note that more than half of the lesion apparently protruded outside the pancreas, and adhered to the gallbladder. (B, C) On microscopic examination, the cyst wall was mainly lined with stratified squamous epithelium and focally lined with flat cuboidal epithelium (B, × 12; C, × 200). No epithelial cells show cellular atypia. The subepithelial layer consisted of thick collagen bundles and lymphoid tissues (C, × 200). (D) A few foci of extraluminal leakage of keratin material with prominent keratin granuloma and multinucleated giant cell reaction were detected (D: left column, black arrows, × 12; right column, × 200) (Pn: pancreas; LEC: lymphoepithelial cyst; GB: gall bladder).
Please cite this article in press as: Ku YM, et al. Exophytic lymphoepithelial cyst of the pancreas. Clin Res Hepatol Gastroenterol (2015), http://dx.doi.org/10.1016/j.clinre.2014.09.004
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Exophytic lymphoepithelial cyst of the pancreas is pathognomonic of ECIS. DCs are frequently complicated with infection and suppuration. Foci of mucinous cells and respiratory-type mucosa are suggestive of DCs. Radiologically, LECs showing exophytic growing can be mistaken as DCs or mucinous neoplasms in the retroperitoneum. The presence of the ‘‘beak sign’’ deforming the edges of an adjacent organ such as the liver, pancreas, or kidneys increases the possible origination from that adjacent organ [2]. LECs could have low SI on T2-weighted MR images [4]. In our case, a few granular foci with low SI within the cyst on T2-weighted MR images corresponded pathologically to keratin material. In cases showing granular low-SI foci within an exophytic cystic mass arising from the pancreas on T2-weighted MR images, the diagnosis of LEC over other cystic lesions could be favored.
Contributors All the authors were involved in patient care, manuscript development and literature review.
3
Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
References [1] Shinmura R, Gabata T, Matsui O. Lymphoepithelial cyst of the pancreas: case report with special reference to imaging-pathologic correlation. Abdom Imaging 2006;31: 106—9. [2] Kim WH, Lee JY, Park HS, et al. Lymphoepithelial cyst of the pancreas: comparison of CT findings with other pancreatic cystic lesions. Abdom Imaging 2013;38:324—30. [3] Adsay NV, Hasteh F, Cheng JD, et al. Lymphoepithelial cysts of the pancreas: a report of 12 cases and a review of the literature. Mod Pathol 2002;15:492—501. [4] Nam SJ, Hwang HK, Kim H, et al. Lymphoepithelial cysts in the pancreas: MRI of two cases with emphasis of diffusion-weighted imaging characteristics. J Magn Reson Imaging 2010;32: 692—6.
Please cite this article in press as: Ku YM, et al. Exophytic lymphoepithelial cyst of the pancreas. Clin Res Hepatol Gastroenterol (2015), http://dx.doi.org/10.1016/j.clinre.2014.09.004
ARTICLE IN PRESS
CLINRE-660; No. of Pages 3
Clinics and Research in Hepatology and Gastroenterology (2015) xxx, xxx—xxx
Available online at
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IMAGE OF THE MONTH
Exophytic lymphoepithelial cyst of the pancreas Young Mi Ku a, Su Lim Lee a, Kee Hwan Kim b, Kyung-Jin Seo c,∗ a
Department of Radiology, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 271 Cheonbo-ro, Uijeongbu 480-717, Republic of Korea b Department of Surgery, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 271 Cheonbo-ro, Uijeongbu 480-717, Republic of Korea c Department of Hospital Pathology, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 271 Cheonbo-ro, Uijeongbu 480-717, Republic of Korea
A 50-year-old man was referred to our institute with a 1month history of epigastric and back pain. Computed tomography detected a bi-locular low attenuating lesion extending from the head of the pancreas (Fig. 1A, arrows) showing the ‘‘beak sign’’ (Fig. 1B, arrow), which can be defined as two lines with an acute angle traced by a mass outline and the adjacent organ (in this case, the pancreas), forming a beak shape. An oval, exophytic pancreatic lesion showed high signal intensity (SI) and some low-SI foci within the lesion on contrastenhanced T1-weighted magnetic resonance (MR) images (Fig. 1C, arrowheads). T1-weighted MR images revealed thick marginal wall enhancement (Fig. 1D, arrow). The differential diagnosis included a mucinous cystic neoplasm of the pancreas and an epidermoid cyst. As a neoplastic lesion could not be ruled out, surgical treatment was performed. The resected pancreas exhibited an exophytic, bi-locular cyst, measuring 5 × 4.5 cm (Fig. 2A). After making an incision, the cyst was observed to be filled with yellow greasy substance. The lesion adhered to the head of the pancreas (Figs. 2A and 2B), and most portions of the cyst apparently
∗
Corresponding author. E-mail address: [email protected] (K.-J. Seo).
protruded outside the pancreas. Microscopically, most of the cyst wall was lined by stratified squamous epithelium and was focally covered by flat cuboidal epithelium (Fig. 2C). The subepithelial layer consisted of a thick collagen bundle and lymphoid tissue (Fig. 2C). A few foci of extraluminal leakage of keratin material (Fig. 2D, left, black arrows) with prominent keratin granulomas (Fig. 2D, right) were also detected. Based on those pathological findings, the lesion was diagnosed as an exophytic lymphoepithelial cyst (LEC) of the pancreas. An LEC, very rare true cyst of the pancreas that was first described by Luchtrath and Schriefers in 1985 [1], is a unior multi-locular cystic lesion lined with squamous epithelium and surrounded by non-neoplastic lymphoid elements [2]. An LEC can be an intrapancreatic or protruding mass from the pancreatic parenchyma [3]. An LEC with an exophytic growth mimics an extra-pancreatic mass such as a pseudocyst, epidermoid cyst, or mucinous neoplasm [3]. One report stated that such lesions are commonly extrapancreatic in location [2]. The key histopathologic findings of LECs are cyst walls being lined with keratinizing epithelium and subepithelial dense lymphoid tissue admixed with germinal centers [3]. The main pathological differentials include dermoid cysts (DCs) and epidermoid cysts in intrapancreatic accessory spleens (ECISs). The presence of splenic red pulp
http://dx.doi.org/10.1016/j.clinre.2014.09.004 2210-7401/© 2014 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Ku YM, et al. Exophytic lymphoepithelial cyst of the pancreas. Clin Res Hepatol Gastroenterol (2015), http://dx.doi.org/10.1016/j.clinre.2014.09.004
+Model CLINRE-660; No. of Pages 3
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ARTICLE IN PRESS Y.M. Ku et al.
Figure 1 (A) Axial computed tomography image showing a bi-locular low attenuating mass (arrows) extending from the head of the pancreas. (B) Coronal image showing the so-called ‘‘beak sign’’ (arrow) adjacent to the lesion. (C) An oval exophytic pancreatic lesion (arrows) with high signal intensity and a few low signal intensity foci within it (arrowheads) on T2-weighted magnetic resonance (MR) image. (D) Contrast-enhanced T1-weighted MR image revealing thick lesion wall enhancement (arrow). No evidence of remarkable upstream pancreatic duct dilatation is visible. (St: stomach; Pn: pancreas).
Figure 2 (A) A photograph of the resected head of the pancreas showing a bi-locular cystic mass, measuring 5 × 4.5 cm. The cyst is filled with a greasy yellow substance. Note that more than half of the lesion apparently protruded outside the pancreas, and adhered to the gallbladder. (B, C) On microscopic examination, the cyst wall was mainly lined with stratified squamous epithelium and focally lined with flat cuboidal epithelium (B, × 12; C, × 200). No epithelial cells show cellular atypia. The subepithelial layer consisted of thick collagen bundles and lymphoid tissues (C, × 200). (D) A few foci of extraluminal leakage of keratin material with prominent keratin granuloma and multinucleated giant cell reaction were detected (D: left column, black arrows, × 12; right column, × 200) (Pn: pancreas; LEC: lymphoepithelial cyst; GB: gall bladder).
Please cite this article in press as: Ku YM, et al. Exophytic lymphoepithelial cyst of the pancreas. Clin Res Hepatol Gastroenterol (2015), http://dx.doi.org/10.1016/j.clinre.2014.09.004
+Model CLINRE-660; No. of Pages 3
ARTICLE IN PRESS
Exophytic lymphoepithelial cyst of the pancreas is pathognomonic of ECIS. DCs are frequently complicated with infection and suppuration. Foci of mucinous cells and respiratory-type mucosa are suggestive of DCs. Radiologically, LECs showing exophytic growing can be mistaken as DCs or mucinous neoplasms in the retroperitoneum. The presence of the ‘‘beak sign’’ deforming the edges of an adjacent organ such as the liver, pancreas, or kidneys increases the possible origination from that adjacent organ [2]. LECs could have low SI on T2-weighted MR images [4]. In our case, a few granular foci with low SI within the cyst on T2-weighted MR images corresponded pathologically to keratin material. In cases showing granular low-SI foci within an exophytic cystic mass arising from the pancreas on T2-weighted MR images, the diagnosis of LEC over other cystic lesions could be favored.
Contributors All the authors were involved in patient care, manuscript development and literature review.
3
Disclosure of interest The authors declare that they have no conflicts of interest concerning this article.
References [1] Shinmura R, Gabata T, Matsui O. Lymphoepithelial cyst of the pancreas: case report with special reference to imaging-pathologic correlation. Abdom Imaging 2006;31: 106—9. [2] Kim WH, Lee JY, Park HS, et al. Lymphoepithelial cyst of the pancreas: comparison of CT findings with other pancreatic cystic lesions. Abdom Imaging 2013;38:324—30. [3] Adsay NV, Hasteh F, Cheng JD, et al. Lymphoepithelial cysts of the pancreas: a report of 12 cases and a review of the literature. Mod Pathol 2002;15:492—501. [4] Nam SJ, Hwang HK, Kim H, et al. Lymphoepithelial cysts in the pancreas: MRI of two cases with emphasis of diffusion-weighted imaging characteristics. J Magn Reson Imaging 2010;32: 692—6.
Please cite this article in press as: Ku YM, et al. Exophytic lymphoepithelial cyst of the pancreas. Clin Res Hepatol Gastroenterol (2015), http://dx.doi.org/10.1016/j.clinre.2014.09.004
