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Acinar cystadenoma of the pancreas: A previously undescribed tumor
CASE REPORTS
Acinar Cystadenoma of the Pancreas: A Previously Undescribed Tumor Jorge Albores-Saavedra, MD A 58-year-old diabetic woman died as a result of an acute myocardial infarction caused by coronary atherosclerosis and thrombosis. A 9 cm multiloculated cystic lesion was found incidentally in the body and tail of the pancreas. The microcysts and locules were lined by one or two layers of normal-appearing acinar cells. In some locules there were clusters of acinar structures containing eosinophilic material. The cuboidal cells lining the locules had morphologic and immunohistochemical features of acinar cells. The lesion was interpreted as an acinar cystadenoma, the benign counterpart of the well-established acinar cystadenocarcinoma of the pancreas. Acinar cystadenoma should be included in the differential diagnosis of cystic tumors of the pancreas. Ann Diagn Pathol 6: 113-115, 2002. Copyright 2002, Elsevier Science (USA). All rights reserved. Index Words: Pancreas, acinar cystadenoma
A
WIDE variety of cystic lesions with characteristic clinical presentation and pathologic features have been described in the pancreas. Most pancreatic cysts are non-neoplastic and the result of acute inflammation or ductal obstruction.1-5 The pathogenesis is unknown in others, such as the lymphoepithelial and enterogenous cysts. Some are neoplastic and have been classified as mucinous cystic tumors,1,2 serous cystadenoma,6 acinar cystadenocarcinoma,7,8 solid and cystic pseudopapillary tumor,9 and intraductal papillary mucinous neoplasms.10 We report here what appears to be the first example of acinar cystadenoma of the pancreas.
Autopsy Findings The most significant pathologic findings included an extensive acute myocardial infarction of the left ventricle and severe atherosclerosis of the left anterior descending coronary artery with a recent thrombus occluding most of its lumen. There also was chronic pyelonephritis and nodular diabetic glomerulosclerosis. A 9 cm well-demarcated, multiloculated cystic lesion containing serous fluid was found in the body and tail of the pancreas (Figs 1 through 4). The thickness of the walls of the locules varied from 1 to 3 mm. The inner surfaces were pink, smooth, and glistening. There were no papillary structures on the inner surfaces of the locules. Seven peripancreatic lymph nodes appeared normal.
Materials and Methods Case Report A 58-year-old female died on arrival at the emergency room as a result of acute heart failure. She had a history of longstanding diabetes mellitus and coronary atherosclerosis.
From the Division of Anatomic Pathology, The University of Texas Southwestern Medical Center, Dallas, TX. Address reprint requests to Jorge Albores-Saavedra, MD, Department of Pathology UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9073. Copyright 2002, Elsevier Science (USA). All rights reserved. 1092-9134/02/0602-0005$35.00/0 doi:10.1053/adpa.2002.32379
Multiple hematoxylin-eosin–stained sections of the cystic pancreatic lesion were available for review. Additional sections were obtained from a representative paraffin block for immunoperoxidase stains. The following antibodies were used: chromogranin (Signet, Dedham, MA; 1:800), synpatophysin (Dako, Carpinteria, CA; 1:200), trypsin (Biodesign; 1:3,200), chymotripsin (Calbiochem, San Diego, CA; 1:800) and lipase (Beckman, Fullerton, CA; 1:320).
Microscopic Findings The locules and microcysts of the cystic pancreatic lesion were lined by one or two layers of normal-appearing cuboidal or flattened acinar cells whose eosinophilic apical cytoplasm was diastase resistant, periodic acidschiff positive (Figs 1,2). Flattened cells resembling duc-
Annals of Diagnostic Pathology, Vol 6, No 2 (April), 2002: pp 113-115
113
114
Jorge Albores-Saavedra
Figure 1. Multiloculated cystic lesions. The locules vary in size and appear empty. A portion of normal pancreas is seen in the lower left corner.
Figure 3. A single layer of acinar cells. Small acinar structures are seen.
tal cells were identified in some locules and small acinar structures containing eosinophilic material in others (Figs 3,4). All acinar cells were confined to the inner surfaces of the locules. There were no tall columnar mucin-containing cells or glycogen-rich cuboidal cells. There were no mitotic figures. The ovarian-like stroma characteristic of the mucinous cystic tumors was not seen in the walls of the locules. There was no continuity between the locules and the normal pancreatic ducts or acini. The adjacent pancreatic parenchyma showed only focal amyloidosis of the islets. The peripancreatic lymph nodes showed no metastases. The lining acinar cells showed immunoreactivity to trypsin and chymotrypsin but did not express lipase. They were also negative for chromogranin and synaptophysin.
The case subject of this report probably represents an example of a previously undescribed pan-
creatic cystic neoplasm, which we have designated acinar cystadenoma, the benign counterpart of the acinar cystadenocarcinoma of the pancreas.7,8 The lack of cytologic atypia, mitotic activity, and extension beyond the wall of the locules allows separation from acinar cystadenocarcinoma. In view that some of the locules and microcysts are lined by flattened cells resembling ductal cells, the possibility that the cystic lesion is metaplastic and of ductal origin cannot be excluded. However, most of the locules of this cystic neoplasm are lined by one or two layers of well-differentiated cuboidal cells with light microscopic and immunohistochemical features of acinar cells. The absence of ovarian-like stroma and goblet cells and columnar mucin-containing cells in the lining epithelium excludes a mucinous cystic neoplasm of the pancreas.11 Cuboidal cells with clear glycogen-rich cytoplasm
Figure 2. Part of a locule lined on both sides by cuboidal and flattened acinar cells.
Figure 4. Some of the acinar structures contain eosinophilic material.
Discussion
Acinar Cystadenoma of the Pancreas
characteristic of serous cystadenoma were not found in this acinar cystadenoma. A non-neoplastic lesion was also considered in the differential diagnosis but was excluded because of the large size of the multiloculated cystic lesion, as well as the absence of ductal obstruction, chronic inflammation, and fibrosis in the adjacent pancreatic tissue. Although the pancreatic acinar cystadenoma reported here was an incidental autopsy finding, it is possible that in the future similar cystic lesions may be symptomatic and detected by imaging techniques. Therefore, acinar cystadenoma, an exceedingly rare lesion, should be considered in the differential diagnosis of cystic neoplasms of the pancreas. References 1. Albores-Saavedra J, Gould EW, Angeles-Angeles A, et al: Cystic tumors of the pancreas. Pathol Annu 1990;25:19-50 2. Albores-Saavedra J, Angeles-Angeles A, Nadji M, et al: Mucinous cystadenocarcinoma of the pancreas. Morphologic and immunocytochemical observations. Am J Surg Pathol 1987; 11:11-20 3. Wilentz RE, Albores-Saavedra J, Zahurak M, et al: Pathologic examination accurately predicts prognosis in mucinous
115
cystic neoplasms of the pancreas. Am J Surg Pathol 1999;23: 1320-1327 4. Albores-Saavedra J, Nadji M, Henson DE, et al: Enteroendocrine cell differentiation in carcinomas of the gallbladder and mucinous cystadenocarcinomas of the pancreas. Pathol Res Pract 1998;183:169-175 5. Zamboni G, Scarpa A, Bogina G, et al: Mucinous cystic tumors of the pancreas: Clinicopathological features, prognosis, and relationship to other mucinous cystic tumors. Am J Surg Pathol 1999;23:410-422 6. Compton CC: Serous cystic tumors of the pancreas. Semin Diagn Pathol 2000;17:43-55 7. Cantrell BB, Cubilla AL, Erlandson RA, et al: Acinar cell cystadenocarcinoma of human pancreas. Cancer 1981;47:410416 8. Stamm B, Burger H, Hollinger A: Acinar cell cystadenocarcinoma of the pancreas. Cancer 1987;60:2542-2547 9. Pettinato G, Manivel JC, Ravetto C, et al: Papillary cystic tumor of the pancreas. A clinicopathologic study of 20 cases with cytologic, immunohistochemical, ultrastructural, and flow cytometric observations, and a review of the literature. Am J Clin Pathol 1992;98:478-488 10. Sessa F, Solcia E, Capella C, et al: Intraductal papillarymucinous tumours represent a distinct group of pancreatic neoplasms: An investigation of tumour cell differentiation and K-ras, p53 and c-erb-2 abnormalities in 26 patients. Virchows Arch 1994;425:357-367 11. Wenig BM, Albores-Saavedra J, Buetow PC, et al: Pancreatic mucinous cystic neoplasm with sarcomatous stroma: A report of three cases. Am J Surg Pathol 1997;21:70-80
Acinar Cystadenoma of the Pancreas: A Previously Undescribed Tumor Jorge Albores-Saavedra, MD A 58-year-old diabetic woman died as a result of an acute myocardial infarction caused by coronary atherosclerosis and thrombosis. A 9 cm multiloculated cystic lesion was found incidentally in the body and tail of the pancreas. The microcysts and locules were lined by one or two layers of normal-appearing acinar cells. In some locules there were clusters of acinar structures containing eosinophilic material. The cuboidal cells lining the locules had morphologic and immunohistochemical features of acinar cells. The lesion was interpreted as an acinar cystadenoma, the benign counterpart of the well-established acinar cystadenocarcinoma of the pancreas. Acinar cystadenoma should be included in the differential diagnosis of cystic tumors of the pancreas. Ann Diagn Pathol 6: 113-115, 2002. Copyright 2002, Elsevier Science (USA). All rights reserved. Index Words: Pancreas, acinar cystadenoma
A
WIDE variety of cystic lesions with characteristic clinical presentation and pathologic features have been described in the pancreas. Most pancreatic cysts are non-neoplastic and the result of acute inflammation or ductal obstruction.1-5 The pathogenesis is unknown in others, such as the lymphoepithelial and enterogenous cysts. Some are neoplastic and have been classified as mucinous cystic tumors,1,2 serous cystadenoma,6 acinar cystadenocarcinoma,7,8 solid and cystic pseudopapillary tumor,9 and intraductal papillary mucinous neoplasms.10 We report here what appears to be the first example of acinar cystadenoma of the pancreas.
Autopsy Findings The most significant pathologic findings included an extensive acute myocardial infarction of the left ventricle and severe atherosclerosis of the left anterior descending coronary artery with a recent thrombus occluding most of its lumen. There also was chronic pyelonephritis and nodular diabetic glomerulosclerosis. A 9 cm well-demarcated, multiloculated cystic lesion containing serous fluid was found in the body and tail of the pancreas (Figs 1 through 4). The thickness of the walls of the locules varied from 1 to 3 mm. The inner surfaces were pink, smooth, and glistening. There were no papillary structures on the inner surfaces of the locules. Seven peripancreatic lymph nodes appeared normal.
Materials and Methods Case Report A 58-year-old female died on arrival at the emergency room as a result of acute heart failure. She had a history of longstanding diabetes mellitus and coronary atherosclerosis.
From the Division of Anatomic Pathology, The University of Texas Southwestern Medical Center, Dallas, TX. Address reprint requests to Jorge Albores-Saavedra, MD, Department of Pathology UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9073. Copyright 2002, Elsevier Science (USA). All rights reserved. 1092-9134/02/0602-0005$35.00/0 doi:10.1053/adpa.2002.32379
Multiple hematoxylin-eosin–stained sections of the cystic pancreatic lesion were available for review. Additional sections were obtained from a representative paraffin block for immunoperoxidase stains. The following antibodies were used: chromogranin (Signet, Dedham, MA; 1:800), synpatophysin (Dako, Carpinteria, CA; 1:200), trypsin (Biodesign; 1:3,200), chymotripsin (Calbiochem, San Diego, CA; 1:800) and lipase (Beckman, Fullerton, CA; 1:320).
Microscopic Findings The locules and microcysts of the cystic pancreatic lesion were lined by one or two layers of normal-appearing cuboidal or flattened acinar cells whose eosinophilic apical cytoplasm was diastase resistant, periodic acidschiff positive (Figs 1,2). Flattened cells resembling duc-
Annals of Diagnostic Pathology, Vol 6, No 2 (April), 2002: pp 113-115
113
114
Jorge Albores-Saavedra
Figure 1. Multiloculated cystic lesions. The locules vary in size and appear empty. A portion of normal pancreas is seen in the lower left corner.
Figure 3. A single layer of acinar cells. Small acinar structures are seen.
tal cells were identified in some locules and small acinar structures containing eosinophilic material in others (Figs 3,4). All acinar cells were confined to the inner surfaces of the locules. There were no tall columnar mucin-containing cells or glycogen-rich cuboidal cells. There were no mitotic figures. The ovarian-like stroma characteristic of the mucinous cystic tumors was not seen in the walls of the locules. There was no continuity between the locules and the normal pancreatic ducts or acini. The adjacent pancreatic parenchyma showed only focal amyloidosis of the islets. The peripancreatic lymph nodes showed no metastases. The lining acinar cells showed immunoreactivity to trypsin and chymotrypsin but did not express lipase. They were also negative for chromogranin and synaptophysin.
The case subject of this report probably represents an example of a previously undescribed pan-
creatic cystic neoplasm, which we have designated acinar cystadenoma, the benign counterpart of the acinar cystadenocarcinoma of the pancreas.7,8 The lack of cytologic atypia, mitotic activity, and extension beyond the wall of the locules allows separation from acinar cystadenocarcinoma. In view that some of the locules and microcysts are lined by flattened cells resembling ductal cells, the possibility that the cystic lesion is metaplastic and of ductal origin cannot be excluded. However, most of the locules of this cystic neoplasm are lined by one or two layers of well-differentiated cuboidal cells with light microscopic and immunohistochemical features of acinar cells. The absence of ovarian-like stroma and goblet cells and columnar mucin-containing cells in the lining epithelium excludes a mucinous cystic neoplasm of the pancreas.11 Cuboidal cells with clear glycogen-rich cytoplasm
Figure 2. Part of a locule lined on both sides by cuboidal and flattened acinar cells.
Figure 4. Some of the acinar structures contain eosinophilic material.
Discussion
Acinar Cystadenoma of the Pancreas
characteristic of serous cystadenoma were not found in this acinar cystadenoma. A non-neoplastic lesion was also considered in the differential diagnosis but was excluded because of the large size of the multiloculated cystic lesion, as well as the absence of ductal obstruction, chronic inflammation, and fibrosis in the adjacent pancreatic tissue. Although the pancreatic acinar cystadenoma reported here was an incidental autopsy finding, it is possible that in the future similar cystic lesions may be symptomatic and detected by imaging techniques. Therefore, acinar cystadenoma, an exceedingly rare lesion, should be considered in the differential diagnosis of cystic neoplasms of the pancreas. References 1. Albores-Saavedra J, Gould EW, Angeles-Angeles A, et al: Cystic tumors of the pancreas. Pathol Annu 1990;25:19-50 2. Albores-Saavedra J, Angeles-Angeles A, Nadji M, et al: Mucinous cystadenocarcinoma of the pancreas. Morphologic and immunocytochemical observations. Am J Surg Pathol 1987; 11:11-20 3. Wilentz RE, Albores-Saavedra J, Zahurak M, et al: Pathologic examination accurately predicts prognosis in mucinous
115
cystic neoplasms of the pancreas. Am J Surg Pathol 1999;23: 1320-1327 4. Albores-Saavedra J, Nadji M, Henson DE, et al: Enteroendocrine cell differentiation in carcinomas of the gallbladder and mucinous cystadenocarcinomas of the pancreas. Pathol Res Pract 1998;183:169-175 5. Zamboni G, Scarpa A, Bogina G, et al: Mucinous cystic tumors of the pancreas: Clinicopathological features, prognosis, and relationship to other mucinous cystic tumors. Am J Surg Pathol 1999;23:410-422 6. Compton CC: Serous cystic tumors of the pancreas. Semin Diagn Pathol 2000;17:43-55 7. Cantrell BB, Cubilla AL, Erlandson RA, et al: Acinar cell cystadenocarcinoma of human pancreas. Cancer 1981;47:410416 8. Stamm B, Burger H, Hollinger A: Acinar cell cystadenocarcinoma of the pancreas. Cancer 1987;60:2542-2547 9. Pettinato G, Manivel JC, Ravetto C, et al: Papillary cystic tumor of the pancreas. A clinicopathologic study of 20 cases with cytologic, immunohistochemical, ultrastructural, and flow cytometric observations, and a review of the literature. Am J Clin Pathol 1992;98:478-488 10. Sessa F, Solcia E, Capella C, et al: Intraductal papillarymucinous tumours represent a distinct group of pancreatic neoplasms: An investigation of tumour cell differentiation and K-ras, p53 and c-erb-2 abnormalities in 26 patients. Virchows Arch 1994;425:357-367 11. Wenig BM, Albores-Saavedra J, Buetow PC, et al: Pancreatic mucinous cystic neoplasm with sarcomatous stroma: A report of three cases. Am J Surg Pathol 1997;21:70-80