536224
research-article2014
IJSXXX10.1177/1066896914536224International Journal of Surgical PathologyShah et al
Case Report
Tumor-to-Tumor Metastasis: Report of Two Cases of Renal Cell Carcinoma Metastasizing to Microcystic Serous Cystadenoma of the Pancreas
International Journal of Surgical Pathology 2015, Vol. 23(1) 48–51 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1066896914536224 ijs.sagepub.com
Lopa Shah, MD1, Gregory Tiesi, MD1, Zubin Bamboat, MD1, Donald McCain, MD, PhD1, Andrew Siegel, MD1, and Ciaran Mannion, MD1
Abstract Metastatic cancer to the pancreas accounts for less than 2% of all pancreatic malignancies. In contrast to other metastatic tumors, renal cell carcinoma (RCC) has a propensity to metastasize as a solitary pancreatic lesion. While symptomatic patients may present with obstructive jaundice, abdominal pain, or gastrointestinal bleeding, the diagnosis of metastatic pancreatic involvement is often made in asymptomatic patients, during follow-up evaluation in the aftermath of an initial diagnosis of renal cell carcinoma. Microcystic serous cystadenoma of the pancreas is an uncommon pancreatic exocrine neoplasm that morphologically resembles conventional (clear cell) RCC, in so far as both tumors are characterized by neoplastic cells with clear cytoplasm, relatively uniform nuclei and scant associated tumor stroma. Herein, we report 2 immunohistochemically confirmed cases of clinically unsuspected metastatic RCC to the pancreas, with the metastatic tumor in each case confined to a preexisting microcystic serous cystadenoma of the pancreas. Keywords tumor-to-tumor metastasis, metastatic renal cell carcinoma, microcystic serous cystadenoma of pancreas
Introduction Although the phenomenon of tumor-to-tumor metastasis was initially recognized more than a century ago, fewer than 200 cases have been reported to date.1,2 Overall, the most common site of origin for the metastasizing tumor is the lung (40% to 50% of donor tumors) and the most common recipient tumor is a renal cell carcinoma (RCC; 40% to 70% of recipient tumors).3-6 Secondary neoplasms of the pancreas are also quite uncommon, with lung cancer the most common metastatic carcinoma to the pancreas.3 Herein, we report 2 cases of tumor-to-tumor metastasis, with RCC as the donor tumor and microcystic serous cystadenoma (MSC), an uncommon benign neoplasm of the exocrine pancreas, as the recipient tumor. Given the cytologic similarities of these 2 entities, the diagnostic challenge posed by the combination of RCC and MSC is discussed, with an emphasis on the role of immunohistochemical stains in discriminating between these 2 entities. To the best of our knowledge, MSC of the pancreas has not been previously reported in cases of tumor-to-tumor metastasis.
discovered on computed tomography scan. A left radical nephrectomy revealed an RCC, conventional (clear cell) type, nuclear grade 2. Approximately 6 months later, in a follow-up computed tomography surveillance scan, a solitary, interval, cystic pancreatic mass was identified. Based on the imaging appearance, a primary pancreatic neoplasm was favored. A distal pancreatectomy and splenectomy were performed, revealing a 4.2 × 3.8 × 3 cm, pancreatic tail mass. On gross examination, this sharply demarcated, honeycombed, white mass was composed of innumerable, small, cystic spaces, filled with clear fluid. In addition, within the substance of this cystic mass, a clearly distinct, well circumscribed, solid, tan-orange nodule was noted and was confined to the multicystic mass (Figure 1). Given these findings and the patient’s history, a diagnosis of metastatic RCC to microcystic serous cystadenoma (MSC) of the pancreas was raised at the time of frozen section. Subsequent histologic evaluation confirmed this suspicion 1
Hackensack University Medical Center, Hackensack, NJ, USA
Case 1 This 71-year-old man presented with fever after screening colonoscopy and a solid left lower pole kidney mass was
Corresponding Author: Ciaran Mannion, HackensackUniversity Medical Center, 30, Prospect Avenue, Hackensack, NJ 07601, USA. Email: [email protected]
Downloaded from ijs.sagepub.com at RMIT UNIVERSITY on March 13, 2015
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Shah et al
Figure 3. Case 1: CK7 immunohistochemical stain showing reactivity in the microcystic serous adenoma (left side), but no reactivity in the metastatic renal cell carcinoma (right side). Figure 1. Case 1: Gross picture of white, pancreatic microcystic serous cystadenoma with tan-orange nodule of metastatic renal cell carcinoma in the lower portion of the mass.
Figure 2. Case 1: Hematoxylin and eosin–stained section showing solid focus of metastatic renal cell carcinoma (upper right corner), embedded within the microcystic serous adenoma.
(Figure 2). The white, multicystic areas showed strong cytokeratin 7 (CK7) immunoreactivity, but no CD10 reactivity (Figure 3). In contrast, the tan, solid nodule within the multicystic mass showed CD10 staining, but no CK7 staining (Figure 4), indicative of metastatic RCC to a pancreatic MSC. In addition, readily identifable Ki67 staining was evident in the metastatic RCC but was scant in the background pancreatic MSC.
Case 2 This 57-year-old man was initially diagnosed with RCC 3 years prior to surgery, following painful hematuria secondary to renal calculi. Despite the patient’s decision to pursue
Figure 4. Case 1: CD10 immunohistochemical stain showing reactivity in metastatic renal cell carcinoma (right corner), but no reactivity in the microcystic serous adenoma.
homeopathic treatment, the tumor progressed. He eventually underwent a laparoscopic left radical nephrectomy and distal pancreatectomy, revealing a 9 × 8.5 × 6.5 cm, yellow-dark red variegated tumor that involved the superior and mid pole of the kidney, in addition to a sharply
Downloaded from ijs.sagepub.com at RMIT UNIVERSITY on March 13, 2015
50
International Journal of Surgical Pathology 23(1)
Discussion
Figure 5. Case 2: Hematoxylin and eosin–stained section showing small, solid focus of metastatic renal cell carcinoma within a pancreatic microcystic serous adenoma (on the right side).
Figure 6. Double chromogen immunostaining showing CD10 positivity in focus of metastatic renal cell carcinoma (brown) and CK7 (red) positivity in pancreatic microcystic serous adenoma.
demarcated, 3 × 2 × 1.8 cm, white, multicystic, pancreatic mass. Histologic evaluation of the renal tumor revealed RCC, conventional (clear cell) type, nuclear grade 2, with invasion of renal blood vessels. The distal pancreatectomy showed a multicystic, honeycombed lesion, consistent with pancreatic MSC. Within the MSC, a 0.3 cm, microscopic, solid focus of clear cells was noted (Figure 5). In addition, a few ducts in the pancreas revealed low-grade pancreatic intraepithelial neoplasia. Immunohistochemical stains showed strong CK7 staining of the microcystic areas, but no staining with CD 10 or PAX8, whereas the small, solid focus of clear cells showed positive staining for CD10 and PAX8 (Figure 6), but were negative for CK7. Based on the distinct immunohistochemical profiles, a diagnosis of metastatic RCC to a preexisting pancreatic MSC was rendered.
Although the occurrence of multiple primary tumors has been reported in up to 8% of patients, tumor-to-tumor metastasis is rare.7 First reported by Berent1 in 1902, fewer than 200 cases have reported to date.4,5 Lung and breast carcinomas are the most frequent donor tumors,2-6 whereas RCC is the most frequent recipient tumor, with metastases to RCC in up to 15% of RCC patients with a widely metastasized synchronous second malignancy.6 Other recipient tumors have included sarcomas, meningiomas, thyroid neoplasms, pituitary adenomas, ovarian neoplasms, colonic polyps, prostatic carcinomas, pancreatic adenocarcinomas, endometrial carcinomas, and seminomas.2-6 In 1968, Campbell et al5 proposed a strict set of 4 criteria that must be satisfied to qualify as a tumor-to-tumor metastasis, namely that (a) more than 1 primary neoplasm exists; (b) the recipient lesion must be a true neoplasm, either benign or malignant; (c) the donor tumor must be a true metastasis with established growth in the recipient tumor, not simply the result of direct extension/contiguous growth from the primary site (“collision tumor”) or embolization of tumor cells; and (d) tumors that have metastasized to the lymphatic system where lymphoreticular malignant tumors already exist are excluded. Secondary pancreatic neoplasms are also uncommon, but well documented, accounting for slightly less than 2% of all pancreatic malignancies.3 The majority of pancreatic metastases are asymptomatic, most often detected during follow up investigations after surgery for a primary lesion or as an incidental finding on imaging studies performed for an unrelated indication.3,8,9 In surgical series, the most frequent primary sites of origin for secondary tumors of the pancreas are lung (23%), kidney (15%), and breast (8%).10,11 In contrast, pancreatic involvement in autopsy series is multifocal and occurs in the setting of relatively widespread metastasis of the primary tumor to multiple organs.12-14 Many more cases (35%) in surgical series are clinically preoperatively suspected to be primary pancreatic tumors.11 Metastatic RCC is distinct from many of these other malignancies in that it has a propensity to manifest as a solitary pancreatic mass.8,14 In such cases, it can clinically mimic a primary pancreatic neoplasm.3,9 The overwhelming majority of RCC metastases to the pancreas seed nonneoplastic pancreatic parenchyma.12,14 However, when the RCC metastasis to the pancreas resides within a preexisting pancreatic neoplasm, as in both of our reported cases, it is apt to be clinically and radiographically occult. It should be noted that RCC and pancreatic MSC may be encountered in patients with von Hippel–Lindau (VHL) disease. However, genetic testing was not performed in either of these 2 cases, as the patient neither had a family history of VHL nor other VHL-related lesions at sites other
Downloaded from ijs.sagepub.com at RMIT UNIVERSITY on March 13, 2015
51
Shah et al than the kidney and pancreas. Although there is a reported case of RCC metastasizing to a pancreatic endocrine neoplasm,15 to the best of our knowledge the cases reported herein are the first two reported cases of RCC metastasizing to pancreatic MSC. MSC of the pancreas accounts for nearly 1% of all exocrine pancreatic tumors. The treatment of MSC is surgical removal. The indications for surgery in patients with pancreatic MSC are symptomatic lesions, those growing on serial imaging or lesions with, suspicious features on computed tomography that raise concern for underlying invasive malignancy.16 A particularly challenging aspect in the cases herein is that the microscopic features of pancreatic MSC and RCC significantly overlap. Indeed, the latter is 1 of 4 entities— the others being pancreatic pseudocysts, pancreatic mucinous cystic neoplasms and lymphangiomas—that must be considered in the differential diagnosis of pancreatic MSC.17 Thorough gross evaluation (as in the recognition of a distinctly different, tan-orange nodule in the larger, white, microcytic mass in case 1) and attentive microscopic examination (the recognition of a small 0.3 cm solid area within an otherwise typical microcystic mass in case 2) are crucial. Finally, it is also important to highlight the role of immunohistochemistry in confirming these morphologic suspicions. The cells of MSC of the pancreas express keratins, including CK7, CA19.9, and CEA, but are negative for CD10 and PAX8, whereas RCC expresses CD10, vimentin and PAX8, but are typically negative for CK7 and CA19. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Berent W. Seltene metastasenbildung. Zentralb. Allg Pathol. 1902;13:406-410. 2. Wimmer JL, Coffey DM, Kaplan AL, Ayala AG, Ro JY. Tumor-to-tumor metastasis with endometrial carcinoma metastatic to squamous cell carcinoma of the cervix: the first reported case. Arch Pathol Lab Med. 2013;137:1825-1828.
3. Petraki C, Vaslamatzis M, Argyrakos T, et al. Tumor to tumor metastasis: report of two cases and review of the literature. Int J Surg Pathol. 2003;11:127-135. 4. Sawada T, Takahashi H, Hasatani K, et al. Tumor to tumor metastasis: report of an autopsy case of lung adenocarcinoma metastasizing to renal cell carcinoma. Intern Med. 2009;48:1525-1529. 5. Campbell LV Jr, Gilbert E, Chamberlain CR Jr, et al. Metastases of cancer to cancer. Cancer. 1968;22:635-643. 6. Sella A, Ro JY. Renal cell carcinoma: best recipient of tumor-to-tumor metastasis. Urology. 1987;30:35-38. 7. Altinok G, Guler G, Sahin A. Tumor metastasis to an oncocytoma. Scand J Urol Nephrol. 1999;33:416-417. 8. Robbins EG 2nd, Franceschi D, Barkin JS. Solitary metastatic tumors to pancreas: a case report and review of literature. Am J Gastroenterol. 1996;91:2414-2417. 9. Hiroka T, Tomida T, Iwasa M, Takahashi K, Kaned M, Tamaki H. Solitary pancreatic metastasis occurring eight years after nephrectomy for renal cell carcinoma. A case report and surgical review. Int J Pancreatol. 1996;19:145153. 10. Deziel DJ. Metastases to the pancreas. In Howard JM, Idezuki YK, Ihse I, Prinz RA, eds. Surgical Diseases of the Pancreas. 3rd ed. Baltimore, MD: Williams & Wilkins; 1998:643-648. 11. Hruban RH. Bishop Pitman M, Klimstra DS. Tumors of the pancreas. In: AFIP Atlas of Tumor Pathology, 4th Series, Fascicle 6. Washington, DC: Armed Forces Institute of Pathology; 2007:325-327. 12. Zerbi A, Ortolando E, Bazano G, Borri A, Beneduce AA, Di Carlo V. Pancreatic metastasis from renal cell carcinoma: which patients benefit from surgical resection? Ann Surg Oncol. 2008;15:1161-1168. 13. Tanis PJ, van der Gaag NA, Busch OR, van Gulik TM, Gouma DJ. Systemic review of pancreatic surgery for metastatic renal cell carcinoma. Br J Surg. 2009;96:579-592. 14. Crippa S, Angelini C, Mussi C, et al. Surgical treatment of metastatic tumor to the pancreas: a single center experience and review of the literature. World J Surg. 2006;30:15361542. 15. Cenkowski M, Gibson IW, Lategan B, Czaykowski P. Tumor to tumor metastasis: report of a case of renal cell carcinoma metastasizing to a pancreatic endocrine neoplasm. J Clin Oncol. 2011;29:e303-e304. 16. Tseng JF, Warshaw AL, Sahani DV, Lauwers GY, Rattner DW, Fernandez-Del Castillo C. Serous cystadenoma of the pancreas: tumor growth rates and recommendation of treatment. Ann Surg. 2005;242:413-419. 17. Wenig BM, Heffess CA, Adair CF. Atlas of Endocrine Pathology. Philadelphia, PA: WB Saunders; 1997:211-214.
Downloaded from ijs.sagepub.com at RMIT UNIVERSITY on March 13, 2015
research-article2014
IJSXXX10.1177/1066896914536224International Journal of Surgical PathologyShah et al
Case Report
Tumor-to-Tumor Metastasis: Report of Two Cases of Renal Cell Carcinoma Metastasizing to Microcystic Serous Cystadenoma of the Pancreas
International Journal of Surgical Pathology 2015, Vol. 23(1) 48–51 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1066896914536224 ijs.sagepub.com
Lopa Shah, MD1, Gregory Tiesi, MD1, Zubin Bamboat, MD1, Donald McCain, MD, PhD1, Andrew Siegel, MD1, and Ciaran Mannion, MD1
Abstract Metastatic cancer to the pancreas accounts for less than 2% of all pancreatic malignancies. In contrast to other metastatic tumors, renal cell carcinoma (RCC) has a propensity to metastasize as a solitary pancreatic lesion. While symptomatic patients may present with obstructive jaundice, abdominal pain, or gastrointestinal bleeding, the diagnosis of metastatic pancreatic involvement is often made in asymptomatic patients, during follow-up evaluation in the aftermath of an initial diagnosis of renal cell carcinoma. Microcystic serous cystadenoma of the pancreas is an uncommon pancreatic exocrine neoplasm that morphologically resembles conventional (clear cell) RCC, in so far as both tumors are characterized by neoplastic cells with clear cytoplasm, relatively uniform nuclei and scant associated tumor stroma. Herein, we report 2 immunohistochemically confirmed cases of clinically unsuspected metastatic RCC to the pancreas, with the metastatic tumor in each case confined to a preexisting microcystic serous cystadenoma of the pancreas. Keywords tumor-to-tumor metastasis, metastatic renal cell carcinoma, microcystic serous cystadenoma of pancreas
Introduction Although the phenomenon of tumor-to-tumor metastasis was initially recognized more than a century ago, fewer than 200 cases have been reported to date.1,2 Overall, the most common site of origin for the metastasizing tumor is the lung (40% to 50% of donor tumors) and the most common recipient tumor is a renal cell carcinoma (RCC; 40% to 70% of recipient tumors).3-6 Secondary neoplasms of the pancreas are also quite uncommon, with lung cancer the most common metastatic carcinoma to the pancreas.3 Herein, we report 2 cases of tumor-to-tumor metastasis, with RCC as the donor tumor and microcystic serous cystadenoma (MSC), an uncommon benign neoplasm of the exocrine pancreas, as the recipient tumor. Given the cytologic similarities of these 2 entities, the diagnostic challenge posed by the combination of RCC and MSC is discussed, with an emphasis on the role of immunohistochemical stains in discriminating between these 2 entities. To the best of our knowledge, MSC of the pancreas has not been previously reported in cases of tumor-to-tumor metastasis.
discovered on computed tomography scan. A left radical nephrectomy revealed an RCC, conventional (clear cell) type, nuclear grade 2. Approximately 6 months later, in a follow-up computed tomography surveillance scan, a solitary, interval, cystic pancreatic mass was identified. Based on the imaging appearance, a primary pancreatic neoplasm was favored. A distal pancreatectomy and splenectomy were performed, revealing a 4.2 × 3.8 × 3 cm, pancreatic tail mass. On gross examination, this sharply demarcated, honeycombed, white mass was composed of innumerable, small, cystic spaces, filled with clear fluid. In addition, within the substance of this cystic mass, a clearly distinct, well circumscribed, solid, tan-orange nodule was noted and was confined to the multicystic mass (Figure 1). Given these findings and the patient’s history, a diagnosis of metastatic RCC to microcystic serous cystadenoma (MSC) of the pancreas was raised at the time of frozen section. Subsequent histologic evaluation confirmed this suspicion 1
Hackensack University Medical Center, Hackensack, NJ, USA
Case 1 This 71-year-old man presented with fever after screening colonoscopy and a solid left lower pole kidney mass was
Corresponding Author: Ciaran Mannion, HackensackUniversity Medical Center, 30, Prospect Avenue, Hackensack, NJ 07601, USA. Email: [email protected]
Downloaded from ijs.sagepub.com at RMIT UNIVERSITY on March 13, 2015
49
Shah et al
Figure 3. Case 1: CK7 immunohistochemical stain showing reactivity in the microcystic serous adenoma (left side), but no reactivity in the metastatic renal cell carcinoma (right side). Figure 1. Case 1: Gross picture of white, pancreatic microcystic serous cystadenoma with tan-orange nodule of metastatic renal cell carcinoma in the lower portion of the mass.
Figure 2. Case 1: Hematoxylin and eosin–stained section showing solid focus of metastatic renal cell carcinoma (upper right corner), embedded within the microcystic serous adenoma.
(Figure 2). The white, multicystic areas showed strong cytokeratin 7 (CK7) immunoreactivity, but no CD10 reactivity (Figure 3). In contrast, the tan, solid nodule within the multicystic mass showed CD10 staining, but no CK7 staining (Figure 4), indicative of metastatic RCC to a pancreatic MSC. In addition, readily identifable Ki67 staining was evident in the metastatic RCC but was scant in the background pancreatic MSC.
Case 2 This 57-year-old man was initially diagnosed with RCC 3 years prior to surgery, following painful hematuria secondary to renal calculi. Despite the patient’s decision to pursue
Figure 4. Case 1: CD10 immunohistochemical stain showing reactivity in metastatic renal cell carcinoma (right corner), but no reactivity in the microcystic serous adenoma.
homeopathic treatment, the tumor progressed. He eventually underwent a laparoscopic left radical nephrectomy and distal pancreatectomy, revealing a 9 × 8.5 × 6.5 cm, yellow-dark red variegated tumor that involved the superior and mid pole of the kidney, in addition to a sharply
Downloaded from ijs.sagepub.com at RMIT UNIVERSITY on March 13, 2015
50
International Journal of Surgical Pathology 23(1)
Discussion
Figure 5. Case 2: Hematoxylin and eosin–stained section showing small, solid focus of metastatic renal cell carcinoma within a pancreatic microcystic serous adenoma (on the right side).
Figure 6. Double chromogen immunostaining showing CD10 positivity in focus of metastatic renal cell carcinoma (brown) and CK7 (red) positivity in pancreatic microcystic serous adenoma.
demarcated, 3 × 2 × 1.8 cm, white, multicystic, pancreatic mass. Histologic evaluation of the renal tumor revealed RCC, conventional (clear cell) type, nuclear grade 2, with invasion of renal blood vessels. The distal pancreatectomy showed a multicystic, honeycombed lesion, consistent with pancreatic MSC. Within the MSC, a 0.3 cm, microscopic, solid focus of clear cells was noted (Figure 5). In addition, a few ducts in the pancreas revealed low-grade pancreatic intraepithelial neoplasia. Immunohistochemical stains showed strong CK7 staining of the microcystic areas, but no staining with CD 10 or PAX8, whereas the small, solid focus of clear cells showed positive staining for CD10 and PAX8 (Figure 6), but were negative for CK7. Based on the distinct immunohistochemical profiles, a diagnosis of metastatic RCC to a preexisting pancreatic MSC was rendered.
Although the occurrence of multiple primary tumors has been reported in up to 8% of patients, tumor-to-tumor metastasis is rare.7 First reported by Berent1 in 1902, fewer than 200 cases have reported to date.4,5 Lung and breast carcinomas are the most frequent donor tumors,2-6 whereas RCC is the most frequent recipient tumor, with metastases to RCC in up to 15% of RCC patients with a widely metastasized synchronous second malignancy.6 Other recipient tumors have included sarcomas, meningiomas, thyroid neoplasms, pituitary adenomas, ovarian neoplasms, colonic polyps, prostatic carcinomas, pancreatic adenocarcinomas, endometrial carcinomas, and seminomas.2-6 In 1968, Campbell et al5 proposed a strict set of 4 criteria that must be satisfied to qualify as a tumor-to-tumor metastasis, namely that (a) more than 1 primary neoplasm exists; (b) the recipient lesion must be a true neoplasm, either benign or malignant; (c) the donor tumor must be a true metastasis with established growth in the recipient tumor, not simply the result of direct extension/contiguous growth from the primary site (“collision tumor”) or embolization of tumor cells; and (d) tumors that have metastasized to the lymphatic system where lymphoreticular malignant tumors already exist are excluded. Secondary pancreatic neoplasms are also uncommon, but well documented, accounting for slightly less than 2% of all pancreatic malignancies.3 The majority of pancreatic metastases are asymptomatic, most often detected during follow up investigations after surgery for a primary lesion or as an incidental finding on imaging studies performed for an unrelated indication.3,8,9 In surgical series, the most frequent primary sites of origin for secondary tumors of the pancreas are lung (23%), kidney (15%), and breast (8%).10,11 In contrast, pancreatic involvement in autopsy series is multifocal and occurs in the setting of relatively widespread metastasis of the primary tumor to multiple organs.12-14 Many more cases (35%) in surgical series are clinically preoperatively suspected to be primary pancreatic tumors.11 Metastatic RCC is distinct from many of these other malignancies in that it has a propensity to manifest as a solitary pancreatic mass.8,14 In such cases, it can clinically mimic a primary pancreatic neoplasm.3,9 The overwhelming majority of RCC metastases to the pancreas seed nonneoplastic pancreatic parenchyma.12,14 However, when the RCC metastasis to the pancreas resides within a preexisting pancreatic neoplasm, as in both of our reported cases, it is apt to be clinically and radiographically occult. It should be noted that RCC and pancreatic MSC may be encountered in patients with von Hippel–Lindau (VHL) disease. However, genetic testing was not performed in either of these 2 cases, as the patient neither had a family history of VHL nor other VHL-related lesions at sites other
Downloaded from ijs.sagepub.com at RMIT UNIVERSITY on March 13, 2015
51
Shah et al than the kidney and pancreas. Although there is a reported case of RCC metastasizing to a pancreatic endocrine neoplasm,15 to the best of our knowledge the cases reported herein are the first two reported cases of RCC metastasizing to pancreatic MSC. MSC of the pancreas accounts for nearly 1% of all exocrine pancreatic tumors. The treatment of MSC is surgical removal. The indications for surgery in patients with pancreatic MSC are symptomatic lesions, those growing on serial imaging or lesions with, suspicious features on computed tomography that raise concern for underlying invasive malignancy.16 A particularly challenging aspect in the cases herein is that the microscopic features of pancreatic MSC and RCC significantly overlap. Indeed, the latter is 1 of 4 entities— the others being pancreatic pseudocysts, pancreatic mucinous cystic neoplasms and lymphangiomas—that must be considered in the differential diagnosis of pancreatic MSC.17 Thorough gross evaluation (as in the recognition of a distinctly different, tan-orange nodule in the larger, white, microcytic mass in case 1) and attentive microscopic examination (the recognition of a small 0.3 cm solid area within an otherwise typical microcystic mass in case 2) are crucial. Finally, it is also important to highlight the role of immunohistochemistry in confirming these morphologic suspicions. The cells of MSC of the pancreas express keratins, including CK7, CA19.9, and CEA, but are negative for CD10 and PAX8, whereas RCC expresses CD10, vimentin and PAX8, but are typically negative for CK7 and CA19. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Berent W. Seltene metastasenbildung. Zentralb. Allg Pathol. 1902;13:406-410. 2. Wimmer JL, Coffey DM, Kaplan AL, Ayala AG, Ro JY. Tumor-to-tumor metastasis with endometrial carcinoma metastatic to squamous cell carcinoma of the cervix: the first reported case. Arch Pathol Lab Med. 2013;137:1825-1828.
3. Petraki C, Vaslamatzis M, Argyrakos T, et al. Tumor to tumor metastasis: report of two cases and review of the literature. Int J Surg Pathol. 2003;11:127-135. 4. Sawada T, Takahashi H, Hasatani K, et al. Tumor to tumor metastasis: report of an autopsy case of lung adenocarcinoma metastasizing to renal cell carcinoma. Intern Med. 2009;48:1525-1529. 5. Campbell LV Jr, Gilbert E, Chamberlain CR Jr, et al. Metastases of cancer to cancer. Cancer. 1968;22:635-643. 6. Sella A, Ro JY. Renal cell carcinoma: best recipient of tumor-to-tumor metastasis. Urology. 1987;30:35-38. 7. Altinok G, Guler G, Sahin A. Tumor metastasis to an oncocytoma. Scand J Urol Nephrol. 1999;33:416-417. 8. Robbins EG 2nd, Franceschi D, Barkin JS. Solitary metastatic tumors to pancreas: a case report and review of literature. Am J Gastroenterol. 1996;91:2414-2417. 9. Hiroka T, Tomida T, Iwasa M, Takahashi K, Kaned M, Tamaki H. Solitary pancreatic metastasis occurring eight years after nephrectomy for renal cell carcinoma. A case report and surgical review. Int J Pancreatol. 1996;19:145153. 10. Deziel DJ. Metastases to the pancreas. In Howard JM, Idezuki YK, Ihse I, Prinz RA, eds. Surgical Diseases of the Pancreas. 3rd ed. Baltimore, MD: Williams & Wilkins; 1998:643-648. 11. Hruban RH. Bishop Pitman M, Klimstra DS. Tumors of the pancreas. In: AFIP Atlas of Tumor Pathology, 4th Series, Fascicle 6. Washington, DC: Armed Forces Institute of Pathology; 2007:325-327. 12. Zerbi A, Ortolando E, Bazano G, Borri A, Beneduce AA, Di Carlo V. Pancreatic metastasis from renal cell carcinoma: which patients benefit from surgical resection? Ann Surg Oncol. 2008;15:1161-1168. 13. Tanis PJ, van der Gaag NA, Busch OR, van Gulik TM, Gouma DJ. Systemic review of pancreatic surgery for metastatic renal cell carcinoma. Br J Surg. 2009;96:579-592. 14. Crippa S, Angelini C, Mussi C, et al. Surgical treatment of metastatic tumor to the pancreas: a single center experience and review of the literature. World J Surg. 2006;30:15361542. 15. Cenkowski M, Gibson IW, Lategan B, Czaykowski P. Tumor to tumor metastasis: report of a case of renal cell carcinoma metastasizing to a pancreatic endocrine neoplasm. J Clin Oncol. 2011;29:e303-e304. 16. Tseng JF, Warshaw AL, Sahani DV, Lauwers GY, Rattner DW, Fernandez-Del Castillo C. Serous cystadenoma of the pancreas: tumor growth rates and recommendation of treatment. Ann Surg. 2005;242:413-419. 17. Wenig BM, Heffess CA, Adair CF. Atlas of Endocrine Pathology. Philadelphia, PA: WB Saunders; 1997:211-214.
Downloaded from ijs.sagepub.com at RMIT UNIVERSITY on March 13, 2015
