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The foamy variant of pancreatic intraepithelial neoplasia
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Annals of Diagnostic Pathology 12 (2008) 252 – 259
The foamy variant of pancreatic intraepithelial neoplasia Jorge Albores-Saavedra, MD a,⁎, Mariana Weimersheimer-Sandoval, MD a , Fredy Chable- Montero, MD a , Daniel Montante-Montes de Oca, MD a , Ralph H. Hruban, MD b,c , Donald Earl Henson, MD d a
Department of Pathology, Instituto Nacional de Ciencias Medicas y Nutrición Salvador Zubirán of Mexico City, Tlalpan 14000, Mexico b Department of Pathology and Oncology, The Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA c Department of Oncology, The Johns Hopkins Medical Institutions. Baltimore, MD 21205, USA d The George Washington University Cancer Institute Office of Cancer Prevention and Control, Washington DC 20037, USA
Abstract
Keywords:
Foamy gland adenocarcinoma is a variant of pancreatic ductal carcinoma, whose precursor has not been described. We describe here the morphologic and immunohistochemical features of the pancreatic intraepithelial neoplasia (PanIN) lesions associated with invasive foamy pancreatic adenocarcinoma. The staining properties and morphologic and immunohistochemical features of 3 foamy PanIN lesions were compared with those of 7 pancreatic foamy gland adenocarcinomas. Hematoxylin and eosin, Mayer mucicarmine, periodic acid-Schiff, and Alcian blue stains were available for review in all cases. Immunohistochemical labeling for cytokeratin (CK)7, CK20, carcinoembryonic antigen polyclonal, MUC1, MUC2, CDX2, p53, and cyclin D1 was performed. The PanIN-1 lesions were found in the nonneoplastic pancreas and were similar to the PanIN-1 lesions of ordinary pancreatic ductal carcinoma. The PanIN-2 and -3 lesions were recognized immediately adjacent to or within the invasive foamy gland carcinoma. In these lesions, small or markedly dilated ducts were lined by cuboidal and columnar dysplastic nonfoamy cells and foamy cells. Hobnail cells were present in 2 cases. The PanIN-1, 2, and 3 lesions and the invasive foamy gland adenocarcinomas stained with mucicarmine, periodic acid-Schiff, and Alcian blue. The 3 PanIN-2 and -3 lesions and all 7 invasive foamy adenocarcinomas labeled with CK7, carcinoembryonic antigen polyclonal, and MUC1, whereas only 2 PanIN-2 and -3 lesions and 5 invasive adenocarcinomas showed immunoreactivity for cyclin D1 and p53. Three distinctive foamy PanIN lesions were identified within 7 invasive foamy gland pancreatic adenocarcinomas. The gradual progression of cytological and architectural abnormalities of the PanIN lesions from PanIN-1 to PanIN-3 excludes neoplastic ductal spread. These foamy PanIN lesions probably represent cancer precursors. © 2008 Elsevier Inc. All rights reserved. Pancreatic intraepitelial neoplasia; Foamy cell; Adenocarcinoma
1. Introduction During the last few years, increasing attention has been devoted to the study of cancer precursors as evidenced by the number of recent publications and extensive reviews on the subject [1-8]. Pancreatic intraepithelial neoplasia (PanIN)
⁎ Corresponding author. E-mail address: [email protected] (J. Albores-Saavedra). 1092-9134/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.anndiagpath.2007.10.002
has now been established as the precursor of ordinary invasive ductal adenocarcinoma of the pancreas based on morphologic, immunohistochemical, and molecular pathology studies [9-15]. There are, however, several distinct variants of ductal pancreatic carcinomas, including adenosquamous carcinoma [16], squamous cell carcinoma [17], medullary carcinoma [18], hepatoid carcinoma [19], colloid carcinoma [20], signet ring cell carcinoma [21], undifferentiated carcinoma with osteoclast-like giant cells [22], and anaplastic spindle and giant cell carcinoma [23]. Several
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Fig. 3. PanIN-1A lesion in nonneoplastic pancreas. A moderately dilated duct is lined by tall columnar mucin-producing cells. Smaller ducts are lined by the same type of epithelium. Fig. 1. Invasive foamy gland adenocarcinoma. Small- and medium-sized glands are lined by columnar cells with abundant foamy cytoplasm.
other histologic variants that appear to be closely related, both clinically and morphologically, to the ordinary invasive ductal adenocarcinoma of the pancreas have also been descrided. These include clear cell carcinoma [24], intestinal type adenocarcinoma [25], and foamy gland carcinoma [26]. It is unlikely that the conventional PanIN lesion can serve as precursor for all variants of carcinomas of the pancreas with ductal phenotype. In fact, we have recently described the intestinal and oncocytic variants of PanIN, which are probably the precursors of the corresponding invasive tumors [27]. We recently reviewed 110 invasive ductal carcinomas of the pancreas and found 4 of foamy gland type [25]. A detailed analysis of these 4 carcinomas led to the recognition of the foamy variant of PanIN. The purpose of this study is to describe the morphologic and immunohistochemical features
Fig. 2. Focal cribriform pattern in an invasive foamy gland adenocarcinoma.
of this new variant of PanIN, which we believe is the precursor of the invasive foamy gland adenocarcinoma. 2. Material and methods Seven invasive foamy gland adenocarcinomas of the pancreas that were surgically resected were reviewed. Four of these carcinomas were included in a previous publication [25], 2 were sent in consultation to one of us (J.A.S.) and 1 additional case was retrieved from the pathology files of the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran of Mexico City. Hematoxylin and eosin– stained sections and Mayer mucicarmine and Alcian blue (pH 2.5) stains as well as the periodic acid-Schiff reaction (PAS) were available for review in all cases. From selected paraffin blocks of 3 tumors containing foci of PanIN lesions, additional sections were obtained for
Fig. 4. PanIN-1B lesion adjacent to normal pancreas.
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3. Results 3.1. Histologic features
immunoperoxidase studies. Immunohistochemical labeling was performed on an automated immunostainer (Ventana Bio Tek System, Ariz) using the standard avidin-biotin peroxidase complex technique and a heat-induced epitope retrieval buffer. The following primary antibodies were used: cytokeratin (CK)7 (dilution 1: 75; Dako, Carpinteria, Calif), CK20 (dilution 1:50; Dako), MUC1 and MUC2, (1:100 dilution for both; Novocastra, Vector Laboratories, Burlingame, Calif), carcinoembryonic antigen polyclonal (CEA; dilution 1: 25; Dako), CDX2 (1: 100 dilution; Novocastra Biotechnology, Santa Cruz, Calif), cyclin D1 (dilution 1:50; Dako), and p53 (prediluted; Dako). Known positive and negative controls were used throughout.
The 7 invasive foamy gland adenocarcinomas of the pancreas included in this investigation were morphologically similar to those described by Adsay et al [25, 26]. They were composed of different size glands lined by cuboidal or columnar cells with an abundant foamy cytoplasm. A focal cribriform pattern was present in 2 neoplasms Most foamy cells had small hyperchromatic nuclei, although larger vesicular nuclei with prominent nucleoli were also noted (Figs. 1 and 2). Of the 7 carcinomas, 4 had a minor component (b20%) of conventional ductal carcinoma of the pancreas. There were no cystically dilated duct-like structures or glands in any of the foamy gland adenocarcinomas. Three of the carcinomas were associated with PanIN lesions. The PanIN-1 lesions were identified in the nonneoplastic pancreas, 5 to 11 mm distant from the invasive carcinoma; they were microscopically similar to those of conventional PanIN-1 lesions of ordinary ductal carcinoma of the pancreas (Figs. 3 and 4). However, PanIN-2 and -3 lesions were found immediately adjacent to or within the foamy gland carcinoma and differed morphologically from the conventional PanIN-2 and -3 lesions of ordinary ductal pancreatic carcinoma. For example, some of the small ducts were markedly dilated, a feature that has not been described in conventional PanIN lesions or in invasive foamy gland adenocarcinomas (Figs. 5-8). Foamy cells similar to those of invasive foamy carcinoma appeared alternating with dysplastic nonfoamy cuboidal or columnar cells in many ducts (Figs. 9 and 10). Gradual transition between the dysplastic cuboidal and columnar cells and the foamy cells was seen. Markedly atypical hobnail cells were occasionally present in small ducts of 2 cases with PanIN-2 and -3 lesions. In 3 invasive foamy gland carcinomas, there was neoplastic
Fig. 6. Higher magnification of duct shown in Fig. 5. Transition between nonfoamy and foamy dysplastic cells.
Fig. 7. Markedly dilated duct with PanIN-2 and -3 lesions foamy and nonfoamy dysplastic cells are seen.
Fig. 5. Moderatly dilated duct with PanIN-2 and -3 lesions. Part of the duct is lined by cuboidal and columnar dysplastic cells. The nuclei are pseudostratified.
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Fig. 8. Higher magnification of lesion shown in Fig. 7. (A) Dysplastic cuboidal cells gradually acquire foamy cytoplasm (hematoxylin and eosin, ×400. (B) Part of the duct is lined exclusively by foamy cells.
Fig. 9. (A) Small duct lined by columnar nonfoamy cells and foamy cells with a micropapillary architecture and (B) higher magnification of duct showing detail of dysplastic foamy and nonfoamy cells and micropapillary pattern.
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Fig. 10. Markedly dilated duct lined partly by dysplastic hobnail and foamy cells.
spread into the ducts characterized by disruption of the ductal wall and penetration of the tumor into the lumen of the ducts, which otherwise showed a normal lining epithelium (Fig. 11). 3.2. Special stains The cells of PanIN-1, -2, and -3 lesions as well as those of the invasive foamy gland carcinomas stained with Alcian blue, mucicarmine, and PAS. Although the apical cytoplasm reacted strongly in a band-like manner, the rest of the cytoplasm was also focally positive with these 3 stains (Fig. 12). 3.3. Immunohistochemistry Most foamy and nonfoamy cells of PanIN-2 and -3 lesions labeled diffusely with CEA. The immunoreactivity was stronger along the apical cytoplasm than in the rest of the cytoplasm. This pattern of reactivity was similar to that seen in the invasive foamy gland carcinoma. Both foamy and nonfoamy cells of PanIN-1, -2, and -3 lesions were immunoreactive for MUC1 and CK7 but were negative for CK20, CDX2, and MUC2 (Fig. 13A and B). Nonfoamy and foamy cells of 2 PanIN-2 and -3 lesions as well as foamy cells of 5 invasive adenocarcinomas showed nuclear accumulation of p53 protein (N35% of cells) and cyclin D1 (Fig. 14A and B).
nent nucleoli were noted in some glands. Foci of conventional ductal carcinoma of the pancreas (b20%) were noted in 4 tumors. In contrast to PanIN lesions, dilated duct-like structures or cystic glands were not identified in any of the invasive foamy gland adenocarcinomas. In the original description of this distinctive variant of ductal pancreatic carcinoma, it was mentioned that “rare dysplastic ducts had foci with foamy change which were interpreted as either the precursors of foamy gland carcinoma or colonization of native ducts by invasive adenocarcinoma” [26]. Unfortunately, diagnostic criteria for these intraductal proliferations were not provided. The gradual progression of cytologic and architectural abnormalities recognized in the intraductal proliferations found in the adjacent nonneoplastic pancreas and immediately adjacent to or within tumor tissue suggests that they are PanIN lesions rather than neoplastic spread into the ducts. The earliest ductal changes occurred in the nonneoplastic pancreas (5 to 11 mm distant from the tumor) and corresponded predominantly to PanIN-1 lesions with few PanIN-2 lesions. The PanIN-1 lesions were similar to the conventional PanIN-1 lesions described in ordinary invasive ductal carcinoma. The high-grade PanIN3 lesions were found immediately adjacent to or within the foamy gland carcinoma. Some of the ducts containing foamy PanIN-2 and -3 lesions were markedly dilated, a feature that is characteristic of intraductal papillary mucinous pancreatic neoplasms but that has not been described in PanIN lesions. The well-developed foamy cell cytoplasm was seen in the PanIN-2 and -3 lesions. However, even in the PanIN-2 and -3 lesions, there were atypical nonfoamy cells, some with hobnail features, not seen in conventional PanIN lesions or in invasive foamy gland carcinoma. It is therefore clear that the PanIN-1 lesions of foamy gland carcinoma are morphologically similar to PanIN-1 lesions described in ordinary ductal pancreatic carcinoma [28,29], whereas the PanIN-2 and -3 lesions differed morphologically from the corresponding conventional PanIN lesions.
4. Discussion The 7 invasive malignant pancreatic neoplasms included in this report fulfilled the morphologic criteria of foamy gland carcinoma [26]. They were characterized by tubular glands of various sizes lined by cuboidal or columnar cells with abundant foamy mucin-containing cytoplasm and small hyperchromatic nuclei. Larger vesicular nuclei with promi-
Fig. 11. Foamy gland adenocarcinoma disrupting the ductal wall and penetrating into the lumen. The ductal epithelium is normal.
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Fig. 12. (A) Positive Alcian blue stain in PanIN3 lesion and (B) invasive foamy gland adenocarcinoma.
As a result, PanIN lesions associated with foamy gland carcinoma are characteristic and can be recognized with hematoxylin and eosin stains. The staining properties (mucicarmine, Alcian blue, and PAS-positive) and immuno-
profile of the high-grade PanIN with foamy change (CEA, MUC1, p53, and cyclin D1–positive), which were similar to those of invasive foamy gland carcinomas, provide additional support to the interpretation that they are cancer precursors.
Fig. 13. (A) Immunoreactivity for MUC1 in PanIN-2 lesion and (B) invasive foamy gland carcinoma.
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Fig. 14. (A) Dilated duct lined by dysplastic cuboidal cells showing immunoreactivity for cyclin D1 and (B) higher magnification showing detail of the cyclin D1 nuclear reactivity.
By contrast, neoplastic spread into the ducts (cancerization of the ducts) recognized in 3 foamy gland carcinomas was characterized by disruption of the ductal wall and penetration of the invasive foamy gland carcinoma into the ducts, which otherwise were lined by a completely normal epithelium. The lack of reactivity for MUC2 and CDX2 shown by the foamy PanIN lesions and the invasive foamy gland adenocarcinomas exclude intestinal differentiation [25]. On the other hand, the positive immunorreactivity for CK7 and MUC1 shown by these lesions suggests pancreatobiliary phenotype [30]. This suggestion is supported by the recognition of a minor component of ordinary pancreatic ductal adenocarcinoma in 4 of the 7 foamy gland adenocarcinomas. Although it is possible that the morphology of PanIN lesions with foamy change is driven by unique genetic changes present in both the foamy gland invasive cancer and in the foamy PanINs, it is also possible that the morphologic changes in both represent a secondary change, possibly from local hypoxia. Mutational analysis of both the foamy variant of PanIN and the invasive foamy gland adenocarcinoma may help to clarify this issue. In conclusion, the foamy type of PanIN-1 lesion is similar to the corresponding conventional type described in ordinary ductal pancreatic carcinoma. During neoplastic progression, the PanIN-2 and -3 lesions gradually develop foamy cells providing the characteristic phenotype. The PanIN foamy lesions can be distinguished from neoplastic spread into the ducts (cancerization of the ducts), which is characterized by disruption of the ductal wall and penetration of the invasive
foamy gland carcinoma into the lumen of the ducts that otherwise show a normal lining epithelium. Additional studies are needed to further characterize this distinctive foamy variant of PanIN lesion. Our results broaden the morphologic spectrum and emphasize the cytologic heterogeneity of the PanIN lesions in general. References [1] Henson DE, Albores-Saavedra J. Pathology of incipient neoplasia. 3rd ed. New York: Oxford University Press; 2001. [2] Berman JL, Albores-Saavedra J, Bostwick D, et al. Precancer: a conceptual working definition. Results of a consensus conference. Cancer Detect Prev 2006;30:387-94. [3] Rohan TE, Henson DE, Franco EL, Albores-Saavedra J. Cancer precursors. In: Schottenfeld D, Fraumeni JF, editors. Cancer epidemiology and prevention. New York: Oxford University Press; 2006. p. 21-46. [4] Henson DE, Albores Saavedra J. Pathology of incipient neoplasia. In: Kelloff G, Hawk E, Sigman CC, editors. Cancer chemoprevention strategies for cancer chemoprevention, vol 2. Totowa, NJ: Humana Press; 2005. p. 69-96. [5] Bostwick DG, Qian J. High-grade prostatic intraepithelial neoplasia. Mod Pathol 2004;17:360-79. [6] Breuer RH, Pasic A, Smith EF, et al. The natural course of preneoplastic lesions in bronchial epithelium. Clin Cancer Res 2005; 11:537-43. [7] Albores-Saavedra J, Krueger JE. C-cell hyperplasia and medullary thyroid microcarcinoma. Endocr Pathol 2001;12:365-77. [8] Franco EL, Rohan TE. Cancer precursors: epidemiology, detection and prevention. New York: Springer-Veilag; 2002. [9] Hruban RH, Wilentz RE, Kern SE. Genetic progression in the pancreatic ducts. Am J Pathol 2000;156:1821-6.
J. Albores-Saavedra et al. / Annals of Diagnostic Pathology 12 (2008) 252–259 [10] Biankin AV, Kench JG, Morey AL, et al. Overexpression of p21waf1/ cip1 is an early event in the development of pancreatic intraepithelial neoplasia. Cancer Res 2001;61:8830-7. [11] Wilentz RE, Iacobuzio-Donahue CA, Argani P, et al. Loss of expression of Dpc4 in pancreatic intraepithelial neoplasia: evidence that Dpc4 inactivation occurs late in neoplastic progression. Cancer Res 2000;60:2002-6. [12] Maruyama H, Kleef J, Wildi S, et al. Id-1 and Id-2 are overexpressed in pancreatic cancer and in dysplastic lesions in chronic pancreatitis. Am J Pathol. 1999; 155-815-822. [13] Goggins M, Hruban RH, Kern SE. BRCA2 is inactivated late in the development of pancreatic intraepithelial neoplasia: evidence and implications. Am J Pathol 2000;156:1767-71. [14] Boschman CR, Stryker S, Reddy JK, et al. Expression of p53 protein in precursor lesions and adenocarcinoma of the of human pancreas. Am J Pathol 1994;145:1291-5. [15] Biankin AV, Kench JG, Biankin SA, et al. Pancreatic intraepithelial neoplasia in association with intraductal mucinous neoplasms of the pancreas. Implications for disease progression and recurrence. Am J Surg Pathol 2004;28:1184-92. [16] Kardon DE, Thompson LD, Przygodzki RM, et al. Adenosquamous carcinoma of the pancreas; a clinicopathologic series of 25 cases. Mod Pathol 2001;14:443-51. [17] Itani KM, Karni A, Green L. Squamous cell carcinoma of the pancreas. J Gastrointest Surg 1999;3:512-5. [18] Wilentz RE, Goggins M, Redston M, et al. Genetic, immunohistochemical and clinical features of medullary carcinomas of the pancreas: a newly described and characterized entity. Am J Pathol 2000;156:1641-51. [19] Hughes K, Kelty S, Martin R. Hepatoid carcinoma of the pancreas. Am Surg 2004;70:1030-3. [20] Luttges J, Beyser K, Prest S, et al. Pancreatic mucinous non-cystic (colloid) carcinomas and intraductal papillary mucinous carcinomas are usually microsatellite stable. Mod Pathol 2003;16:537-42.
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[21] Tracey KJ, O'Brien MJ, Williams LF, et al. Signet ring carcinomas of the pancreas, a rare variant with very high CEA values. Immunohistochemical comparison with adenocarcinoma. Dig Dis Sci 1984;29: 573-6. [22] Molberg KH, Heffes CS, Delgado R, et al. Undifferentiated carcinoma with osteoclast-like giant cells of the pancreas and periampullary region. Cancer 1998;82:1279-87. [23] Paal E, Thompson LD, Frommelt RA, et al. A clinicopathologic and immunohistochemical study of 35 anaplastic carcinomas of the pancreas with a review of the literature. Ann Diagn Pathol 2001;5: 129-40. [24] Ray S, Lu Z, Rajendiran S. Clear cell ductal adenocarcinoma of the pancreas; a case report and review of the literature. Arch Pathol Lab Med 2004;128:693-6. [25] Albores-Saavedra J, Simpson K, Dancer YJ, Hruban R. Intestinal type adenocarcinoma: a previously unrecognized variant of ductal carcinoma of the pancreas. Ann Diagn Pathol 2007;11:3-9. [26] Adsay NV, Logani S, Sarker F, et al. Foamy gland pattern of pancreatic ductal adenocarcinoma: a deceptively benign-appearing variant. Am J Surg Pathol 2000;24:493-504. [27] Albores-Saavedra J, Wu J, Crook T, et al. Intestinal and oncocytic variants of pancreatic intraepithelial neoplasia. A morphological and immunohistochemical study. Ann Diagn Pathol 2005;9:69-76. [28] Hruban RH, Goggins M, Parsons JL, et al. Progression model for pancreatic cancer. Clin Cancer Res 2000;6:2969-72. [29] Hruban RH, Takaori K, Klimstra DS, Adsay NV, Albores-Saavedra J, et al. An illustrated consensus on the classification of pancreatic intraepithelial neoplasia and intraductal papillary mucinous neoplasms. Am J Surg Pathol 2004;28:977-87. [30] Hruban RH, Adsay NV, Albores-Saavedra J, et al. Pancreatic intraepithelial neoplasia: a new nomenclature and classification system for pancreatic duct lesions. Am J Surg Pathol 2001;25: 579-86.
Annals of Diagnostic Pathology 12 (2008) 252 – 259
The foamy variant of pancreatic intraepithelial neoplasia Jorge Albores-Saavedra, MD a,⁎, Mariana Weimersheimer-Sandoval, MD a , Fredy Chable- Montero, MD a , Daniel Montante-Montes de Oca, MD a , Ralph H. Hruban, MD b,c , Donald Earl Henson, MD d a
Department of Pathology, Instituto Nacional de Ciencias Medicas y Nutrición Salvador Zubirán of Mexico City, Tlalpan 14000, Mexico b Department of Pathology and Oncology, The Johns Hopkins Medical Institutions, Baltimore, MD 21205, USA c Department of Oncology, The Johns Hopkins Medical Institutions. Baltimore, MD 21205, USA d The George Washington University Cancer Institute Office of Cancer Prevention and Control, Washington DC 20037, USA
Abstract
Keywords:
Foamy gland adenocarcinoma is a variant of pancreatic ductal carcinoma, whose precursor has not been described. We describe here the morphologic and immunohistochemical features of the pancreatic intraepithelial neoplasia (PanIN) lesions associated with invasive foamy pancreatic adenocarcinoma. The staining properties and morphologic and immunohistochemical features of 3 foamy PanIN lesions were compared with those of 7 pancreatic foamy gland adenocarcinomas. Hematoxylin and eosin, Mayer mucicarmine, periodic acid-Schiff, and Alcian blue stains were available for review in all cases. Immunohistochemical labeling for cytokeratin (CK)7, CK20, carcinoembryonic antigen polyclonal, MUC1, MUC2, CDX2, p53, and cyclin D1 was performed. The PanIN-1 lesions were found in the nonneoplastic pancreas and were similar to the PanIN-1 lesions of ordinary pancreatic ductal carcinoma. The PanIN-2 and -3 lesions were recognized immediately adjacent to or within the invasive foamy gland carcinoma. In these lesions, small or markedly dilated ducts were lined by cuboidal and columnar dysplastic nonfoamy cells and foamy cells. Hobnail cells were present in 2 cases. The PanIN-1, 2, and 3 lesions and the invasive foamy gland adenocarcinomas stained with mucicarmine, periodic acid-Schiff, and Alcian blue. The 3 PanIN-2 and -3 lesions and all 7 invasive foamy adenocarcinomas labeled with CK7, carcinoembryonic antigen polyclonal, and MUC1, whereas only 2 PanIN-2 and -3 lesions and 5 invasive adenocarcinomas showed immunoreactivity for cyclin D1 and p53. Three distinctive foamy PanIN lesions were identified within 7 invasive foamy gland pancreatic adenocarcinomas. The gradual progression of cytological and architectural abnormalities of the PanIN lesions from PanIN-1 to PanIN-3 excludes neoplastic ductal spread. These foamy PanIN lesions probably represent cancer precursors. © 2008 Elsevier Inc. All rights reserved. Pancreatic intraepitelial neoplasia; Foamy cell; Adenocarcinoma
1. Introduction During the last few years, increasing attention has been devoted to the study of cancer precursors as evidenced by the number of recent publications and extensive reviews on the subject [1-8]. Pancreatic intraepithelial neoplasia (PanIN)
⁎ Corresponding author. E-mail address: [email protected] (J. Albores-Saavedra). 1092-9134/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.anndiagpath.2007.10.002
has now been established as the precursor of ordinary invasive ductal adenocarcinoma of the pancreas based on morphologic, immunohistochemical, and molecular pathology studies [9-15]. There are, however, several distinct variants of ductal pancreatic carcinomas, including adenosquamous carcinoma [16], squamous cell carcinoma [17], medullary carcinoma [18], hepatoid carcinoma [19], colloid carcinoma [20], signet ring cell carcinoma [21], undifferentiated carcinoma with osteoclast-like giant cells [22], and anaplastic spindle and giant cell carcinoma [23]. Several
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253
Fig. 3. PanIN-1A lesion in nonneoplastic pancreas. A moderately dilated duct is lined by tall columnar mucin-producing cells. Smaller ducts are lined by the same type of epithelium. Fig. 1. Invasive foamy gland adenocarcinoma. Small- and medium-sized glands are lined by columnar cells with abundant foamy cytoplasm.
other histologic variants that appear to be closely related, both clinically and morphologically, to the ordinary invasive ductal adenocarcinoma of the pancreas have also been descrided. These include clear cell carcinoma [24], intestinal type adenocarcinoma [25], and foamy gland carcinoma [26]. It is unlikely that the conventional PanIN lesion can serve as precursor for all variants of carcinomas of the pancreas with ductal phenotype. In fact, we have recently described the intestinal and oncocytic variants of PanIN, which are probably the precursors of the corresponding invasive tumors [27]. We recently reviewed 110 invasive ductal carcinomas of the pancreas and found 4 of foamy gland type [25]. A detailed analysis of these 4 carcinomas led to the recognition of the foamy variant of PanIN. The purpose of this study is to describe the morphologic and immunohistochemical features
Fig. 2. Focal cribriform pattern in an invasive foamy gland adenocarcinoma.
of this new variant of PanIN, which we believe is the precursor of the invasive foamy gland adenocarcinoma. 2. Material and methods Seven invasive foamy gland adenocarcinomas of the pancreas that were surgically resected were reviewed. Four of these carcinomas were included in a previous publication [25], 2 were sent in consultation to one of us (J.A.S.) and 1 additional case was retrieved from the pathology files of the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran of Mexico City. Hematoxylin and eosin– stained sections and Mayer mucicarmine and Alcian blue (pH 2.5) stains as well as the periodic acid-Schiff reaction (PAS) were available for review in all cases. From selected paraffin blocks of 3 tumors containing foci of PanIN lesions, additional sections were obtained for
Fig. 4. PanIN-1B lesion adjacent to normal pancreas.
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3. Results 3.1. Histologic features
immunoperoxidase studies. Immunohistochemical labeling was performed on an automated immunostainer (Ventana Bio Tek System, Ariz) using the standard avidin-biotin peroxidase complex technique and a heat-induced epitope retrieval buffer. The following primary antibodies were used: cytokeratin (CK)7 (dilution 1: 75; Dako, Carpinteria, Calif), CK20 (dilution 1:50; Dako), MUC1 and MUC2, (1:100 dilution for both; Novocastra, Vector Laboratories, Burlingame, Calif), carcinoembryonic antigen polyclonal (CEA; dilution 1: 25; Dako), CDX2 (1: 100 dilution; Novocastra Biotechnology, Santa Cruz, Calif), cyclin D1 (dilution 1:50; Dako), and p53 (prediluted; Dako). Known positive and negative controls were used throughout.
The 7 invasive foamy gland adenocarcinomas of the pancreas included in this investigation were morphologically similar to those described by Adsay et al [25, 26]. They were composed of different size glands lined by cuboidal or columnar cells with an abundant foamy cytoplasm. A focal cribriform pattern was present in 2 neoplasms Most foamy cells had small hyperchromatic nuclei, although larger vesicular nuclei with prominent nucleoli were also noted (Figs. 1 and 2). Of the 7 carcinomas, 4 had a minor component (b20%) of conventional ductal carcinoma of the pancreas. There were no cystically dilated duct-like structures or glands in any of the foamy gland adenocarcinomas. Three of the carcinomas were associated with PanIN lesions. The PanIN-1 lesions were identified in the nonneoplastic pancreas, 5 to 11 mm distant from the invasive carcinoma; they were microscopically similar to those of conventional PanIN-1 lesions of ordinary ductal carcinoma of the pancreas (Figs. 3 and 4). However, PanIN-2 and -3 lesions were found immediately adjacent to or within the foamy gland carcinoma and differed morphologically from the conventional PanIN-2 and -3 lesions of ordinary ductal pancreatic carcinoma. For example, some of the small ducts were markedly dilated, a feature that has not been described in conventional PanIN lesions or in invasive foamy gland adenocarcinomas (Figs. 5-8). Foamy cells similar to those of invasive foamy carcinoma appeared alternating with dysplastic nonfoamy cuboidal or columnar cells in many ducts (Figs. 9 and 10). Gradual transition between the dysplastic cuboidal and columnar cells and the foamy cells was seen. Markedly atypical hobnail cells were occasionally present in small ducts of 2 cases with PanIN-2 and -3 lesions. In 3 invasive foamy gland carcinomas, there was neoplastic
Fig. 6. Higher magnification of duct shown in Fig. 5. Transition between nonfoamy and foamy dysplastic cells.
Fig. 7. Markedly dilated duct with PanIN-2 and -3 lesions foamy and nonfoamy dysplastic cells are seen.
Fig. 5. Moderatly dilated duct with PanIN-2 and -3 lesions. Part of the duct is lined by cuboidal and columnar dysplastic cells. The nuclei are pseudostratified.
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Fig. 8. Higher magnification of lesion shown in Fig. 7. (A) Dysplastic cuboidal cells gradually acquire foamy cytoplasm (hematoxylin and eosin, ×400. (B) Part of the duct is lined exclusively by foamy cells.
Fig. 9. (A) Small duct lined by columnar nonfoamy cells and foamy cells with a micropapillary architecture and (B) higher magnification of duct showing detail of dysplastic foamy and nonfoamy cells and micropapillary pattern.
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Fig. 10. Markedly dilated duct lined partly by dysplastic hobnail and foamy cells.
spread into the ducts characterized by disruption of the ductal wall and penetration of the tumor into the lumen of the ducts, which otherwise showed a normal lining epithelium (Fig. 11). 3.2. Special stains The cells of PanIN-1, -2, and -3 lesions as well as those of the invasive foamy gland carcinomas stained with Alcian blue, mucicarmine, and PAS. Although the apical cytoplasm reacted strongly in a band-like manner, the rest of the cytoplasm was also focally positive with these 3 stains (Fig. 12). 3.3. Immunohistochemistry Most foamy and nonfoamy cells of PanIN-2 and -3 lesions labeled diffusely with CEA. The immunoreactivity was stronger along the apical cytoplasm than in the rest of the cytoplasm. This pattern of reactivity was similar to that seen in the invasive foamy gland carcinoma. Both foamy and nonfoamy cells of PanIN-1, -2, and -3 lesions were immunoreactive for MUC1 and CK7 but were negative for CK20, CDX2, and MUC2 (Fig. 13A and B). Nonfoamy and foamy cells of 2 PanIN-2 and -3 lesions as well as foamy cells of 5 invasive adenocarcinomas showed nuclear accumulation of p53 protein (N35% of cells) and cyclin D1 (Fig. 14A and B).
nent nucleoli were noted in some glands. Foci of conventional ductal carcinoma of the pancreas (b20%) were noted in 4 tumors. In contrast to PanIN lesions, dilated duct-like structures or cystic glands were not identified in any of the invasive foamy gland adenocarcinomas. In the original description of this distinctive variant of ductal pancreatic carcinoma, it was mentioned that “rare dysplastic ducts had foci with foamy change which were interpreted as either the precursors of foamy gland carcinoma or colonization of native ducts by invasive adenocarcinoma” [26]. Unfortunately, diagnostic criteria for these intraductal proliferations were not provided. The gradual progression of cytologic and architectural abnormalities recognized in the intraductal proliferations found in the adjacent nonneoplastic pancreas and immediately adjacent to or within tumor tissue suggests that they are PanIN lesions rather than neoplastic spread into the ducts. The earliest ductal changes occurred in the nonneoplastic pancreas (5 to 11 mm distant from the tumor) and corresponded predominantly to PanIN-1 lesions with few PanIN-2 lesions. The PanIN-1 lesions were similar to the conventional PanIN-1 lesions described in ordinary invasive ductal carcinoma. The high-grade PanIN3 lesions were found immediately adjacent to or within the foamy gland carcinoma. Some of the ducts containing foamy PanIN-2 and -3 lesions were markedly dilated, a feature that is characteristic of intraductal papillary mucinous pancreatic neoplasms but that has not been described in PanIN lesions. The well-developed foamy cell cytoplasm was seen in the PanIN-2 and -3 lesions. However, even in the PanIN-2 and -3 lesions, there were atypical nonfoamy cells, some with hobnail features, not seen in conventional PanIN lesions or in invasive foamy gland carcinoma. It is therefore clear that the PanIN-1 lesions of foamy gland carcinoma are morphologically similar to PanIN-1 lesions described in ordinary ductal pancreatic carcinoma [28,29], whereas the PanIN-2 and -3 lesions differed morphologically from the corresponding conventional PanIN lesions.
4. Discussion The 7 invasive malignant pancreatic neoplasms included in this report fulfilled the morphologic criteria of foamy gland carcinoma [26]. They were characterized by tubular glands of various sizes lined by cuboidal or columnar cells with abundant foamy mucin-containing cytoplasm and small hyperchromatic nuclei. Larger vesicular nuclei with promi-
Fig. 11. Foamy gland adenocarcinoma disrupting the ductal wall and penetrating into the lumen. The ductal epithelium is normal.
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Fig. 12. (A) Positive Alcian blue stain in PanIN3 lesion and (B) invasive foamy gland adenocarcinoma.
As a result, PanIN lesions associated with foamy gland carcinoma are characteristic and can be recognized with hematoxylin and eosin stains. The staining properties (mucicarmine, Alcian blue, and PAS-positive) and immuno-
profile of the high-grade PanIN with foamy change (CEA, MUC1, p53, and cyclin D1–positive), which were similar to those of invasive foamy gland carcinomas, provide additional support to the interpretation that they are cancer precursors.
Fig. 13. (A) Immunoreactivity for MUC1 in PanIN-2 lesion and (B) invasive foamy gland carcinoma.
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Fig. 14. (A) Dilated duct lined by dysplastic cuboidal cells showing immunoreactivity for cyclin D1 and (B) higher magnification showing detail of the cyclin D1 nuclear reactivity.
By contrast, neoplastic spread into the ducts (cancerization of the ducts) recognized in 3 foamy gland carcinomas was characterized by disruption of the ductal wall and penetration of the invasive foamy gland carcinoma into the ducts, which otherwise were lined by a completely normal epithelium. The lack of reactivity for MUC2 and CDX2 shown by the foamy PanIN lesions and the invasive foamy gland adenocarcinomas exclude intestinal differentiation [25]. On the other hand, the positive immunorreactivity for CK7 and MUC1 shown by these lesions suggests pancreatobiliary phenotype [30]. This suggestion is supported by the recognition of a minor component of ordinary pancreatic ductal adenocarcinoma in 4 of the 7 foamy gland adenocarcinomas. Although it is possible that the morphology of PanIN lesions with foamy change is driven by unique genetic changes present in both the foamy gland invasive cancer and in the foamy PanINs, it is also possible that the morphologic changes in both represent a secondary change, possibly from local hypoxia. Mutational analysis of both the foamy variant of PanIN and the invasive foamy gland adenocarcinoma may help to clarify this issue. In conclusion, the foamy type of PanIN-1 lesion is similar to the corresponding conventional type described in ordinary ductal pancreatic carcinoma. During neoplastic progression, the PanIN-2 and -3 lesions gradually develop foamy cells providing the characteristic phenotype. The PanIN foamy lesions can be distinguished from neoplastic spread into the ducts (cancerization of the ducts), which is characterized by disruption of the ductal wall and penetration of the invasive
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