Path. Res. Pract. 188, 191-198 (1992)
N onfunctioning Pancreatic Endocrine Tumors An Immunohistochemical and Electron Microscopic Analysis of 26 Cases Tong-hua Liul, Yu Zhu 2 , Quan-cai Cuil, Li-xing Cai 2 , Sheng-feng Yel, Shou-xian Zhong 2 and Hong-ping Jia 1 lDepartments of Pathology and 2Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, AR. China
SUMMARY Twenty-six patients with non-functioning pancreatic endocrine tumor (NFPET) were operated on during a 22-year period (1968-1990) at PUMC Hospital, Beijing. Gf these, 19 were female and 7 were male with a mean age of33 years. All these tumors, including 12 malignant and 14 benign, were solitary, and most of them were well-encapsulated. Immunohistochemical staining showed 23 (88.5 %) containing 1-4 kinds of peptide hormone and 18 (69.2 %) being multihormonal. In 7 of the 9 tumors subjected to electron microscopic study, various amounts of neurosecretory granules were found. Tumors of this series were clinically silent, but they contained some immunoreactive peptides, although the amount of the peptides varied from tumor to tumor.
Introducrion Nonfunctioning pancreatic endocrine tumors (NFPETs) or nonfunctioning islet cell tumors (NFICTs) are rare; they account for 10% to 25 % 1,7, 9 of the total pancreatic endocrine tumors. Usually, these tumors show some nonspecific clinical manifestations only, such as abdominal mass, abdominal pain, jaundice, gastrointestinal (GI) tract bleeding, etc, because of their nonfunctioning or nonsecreting character. By virtue of the application of sensitive immunological techniques such as radioimmunoassay (RIA) and immunohistochemistry, most of NFPETs are found to be "secreting" instead of "nonsecreting" , and some NFPETs are even multihormonal. Gwing to the lack of specific physiological action, tumors containing pancreatic polypeptide (PPoma) are gene rally clinically silent; thus some people considered that NFPET may represent unidentified PPoma. Actually, after careful investigation, in some ca ses of NFPET, high level of pancreatic polypeptide in serum and large amount of immunopositive pp cells in tumor tissues were found. In the series of pancreatic endocrine tumors reported by Heitz © 1992 hy Gustav Fischer Verlag, Stuttgart
et al.s, 40 patients showing abdominal mass, pain, jaundice, etc, did not suffer from hormonally induced symptoms. In 10 of them, an elevated serum level of pancreatic polypeptide (PP) was found, and the tumors in these cases were labelIed as PPoma because immunoreactive PP cells were also found in all of them. In order to probe into the endocrine nature of NFPETs, the clinical, pathological, immunohistochemical and ultrastructural characteristics of aseries of surgically resected NFPETs were studied and analyzed. Material and Methods From June 1968 to June 1990, 26 cases of NFPET were diagnosed and treated in PUMC Hospital. In one case, only a biopsy was taken during operation because of extensive liver metastasis. Surgical resections were performed in all the other 25 cases. Tumor tissues were fixed in 10 % neutral formalin, the biopsy material and 4-8 tissue blocks from each of the 25 resected tumors were embedded in paraffin. Routine paraffin sections were stained with hematoxylin-eosin (HE), and some were also 0344-0338/92/0188-0191$3.50/0
192 . Tong-hua Liu et al. Table 1. Working dilution and source of antibodies
Table 2. Mode of operation
Antibody
Dilution
Source
Mode of operation
anti-insulin (porcine) anti-glucagon anti-somatostatin anti-NSE anti-PP
1: 100 1:400 1:600 1: 1,000 1: 10,000
Simple extirpation of islet tumor
7
anti-neurotensin
1: 1,000
anti-VIP anti-hCG(alpha) anti-hCG(beta)
1: 1,000 1:600 1:600
Miles Yeda DAKO Patt DAKO Patt DAKO Patt Gift from Dr. Chance, Lilly Lab. USA Gift from Dr. Polak, Royal Postgraduate Med School, London Immuno Nuclear Corp. UCB-Bioproducts UCB-Bioproducts
No.of cases
Extirpation of islet tumor with: 1) Segmental resection of common bile duct, 1 choledochostomy 2) Segmental resection involving small intestine, 4 end to end anastomosis (1 case with splenectomy) Extirpation of pheochromocytoma concomitantly 4) T-tube drainage of common bile duct 5) Partial resection of portal vein, end to end portal vein anastomosis and superior mesenterlC
stained according to periodic acid/Schiff (PAS) procedure and/or with reticulum stain. For immunohistochemical study, 2 to 4 paraffin blocks from each of the 25 surgically resccted tumors and the paraffin block embedding the specimens from the biopsy case were cut into serial sections of 5 [! thick. Peroxidase antiperoxidase (PAP) technique was used for all primary antibodies except anti-insulin, for which the indirect immunoperoxidase method was employed. The immunohistochemical staining for tumors, positive and negative controls were all the same as previously reported 8 • All primary antibodies were incubated at 4°C overnight. The primary antibodies used, their dilution and sources are listed in Table 1. Fresh tumor tissue from 9 cases was fixed in 2.5 % cold glutaraldehyde, postfixed in 1 % osmium tetraoxide, embedded in Epon 618. Sections of 1 [! thick were stained with toluidine blue for light microscopy while ultrathin sections were stained with uranyl acetate and lead citrate and examined under H-600 transmission electron microscope.
Results Clinical Features
Among the 26 patients, 19 were female and 7 were male, giving a male to female ratio of 1: 2.7. Ages ranged from 12 to 73 years, with a mean of 33 years. The majority of female patients were young or middle-aged, being 12 to 49 years, averaging 24.6 years. The male patients were significantly older than the female ones, being 40 to 73 years, and 55.7 years on average. The clinical symptoms and signs were nonspecific. Abdominal mass and abdominal pain were most common; and GI bleeding, nausea vomiting, anorexia, fever and jaundice were less frequently found. One patient suffered from rupture of esophageal varicose vein due to portal hypertension. Another patient had a pheochromocytoma in the right adrenal (multiple endocrine neoplasm IV, MEN IV) in addition to the NFPET in the pancreas. Her chief complaints were paroxysmal dizziness, headache and palpitation. Surgical Management and Prognosis
Twenty-five patients were subjected to different kinds of operation (Table 2}, The tumor was malignant in 12 (46.2 %) of the 26 cases, with regionallymph-node and/or
artery graft Distal partial resection of tumor bearing pancreas (body and tail) 1) Without splenectomy 1 2) With splenectomy 4 3) Roux- Y pancreatico-enterostomy 1 Pancrcatico-duodenectomy
3
Laparotomy
1
liver metastasis as found during operation in 4 ca ses and retroperitoneal meta stasis in 1 case of them. Two tumors invaded the inferior vena cava and pancreatic vein. Follow-up observation showed that lymph-node, liver and/or abdominal metastasis developed in 3 patients during 3-7 postoperative years, and the tumor recurred in 1 case 9 years after operation. One tumor originating from the pancreatic head extended diffusely into the body and tail of the pancreas. Three patients died postoperatively, 9 patients were lost from follow-up, and the remaining 14 patients have been followed for from 2 months to 7 years, and found to be alive with or without tumors. Pathology
All tumors were solitary as demonstrated by careful examination, completely or partially encapsulated and clearly circumscribed. Some tumors had very thick and tough fibrous capsules. On cut surfaces, the tumors were greyish white in color, homogeneous, usually associated with areas of hemorrhage and/or necrosis (Fig. 1). Some tumors showed cystic change of different sizes. The largest diameter of the tumors ranged from 3.5 cm to 20 cm, with an average of 9.9 cm. Fourteen tumors (53.8 %) were located in the head of the pancreas, 2 (7.7 %) in the body, 5 (19.8 %) in the tail and 4 (15.4 %) in the body-tail. In the remaining one case . (3.8 %), the exact site of the tumor could not be identified. Histologically, tumor cells were similar to those of functioning pancreatic endocrine tumors in shape and size. They were polygonal, low columnar, small round or oval
Non-functioning Pancreati c Endocrine Tumors· 193
N onfunctioning Pancreatic Endocrine Tumors An Immunohistochemical and Electron Microscopic Analysis of 26 Cases Tong-hua Liul, Yu Zhu 2 , Quan-cai Cuil, Li-xing Cai 2 , Sheng-feng Yel, Shou-xian Zhong 2 and Hong-ping Jia 1 lDepartments of Pathology and 2Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, AR. China
SUMMARY Twenty-six patients with non-functioning pancreatic endocrine tumor (NFPET) were operated on during a 22-year period (1968-1990) at PUMC Hospital, Beijing. Gf these, 19 were female and 7 were male with a mean age of33 years. All these tumors, including 12 malignant and 14 benign, were solitary, and most of them were well-encapsulated. Immunohistochemical staining showed 23 (88.5 %) containing 1-4 kinds of peptide hormone and 18 (69.2 %) being multihormonal. In 7 of the 9 tumors subjected to electron microscopic study, various amounts of neurosecretory granules were found. Tumors of this series were clinically silent, but they contained some immunoreactive peptides, although the amount of the peptides varied from tumor to tumor.
Introducrion Nonfunctioning pancreatic endocrine tumors (NFPETs) or nonfunctioning islet cell tumors (NFICTs) are rare; they account for 10% to 25 % 1,7, 9 of the total pancreatic endocrine tumors. Usually, these tumors show some nonspecific clinical manifestations only, such as abdominal mass, abdominal pain, jaundice, gastrointestinal (GI) tract bleeding, etc, because of their nonfunctioning or nonsecreting character. By virtue of the application of sensitive immunological techniques such as radioimmunoassay (RIA) and immunohistochemistry, most of NFPETs are found to be "secreting" instead of "nonsecreting" , and some NFPETs are even multihormonal. Gwing to the lack of specific physiological action, tumors containing pancreatic polypeptide (PPoma) are gene rally clinically silent; thus some people considered that NFPET may represent unidentified PPoma. Actually, after careful investigation, in some ca ses of NFPET, high level of pancreatic polypeptide in serum and large amount of immunopositive pp cells in tumor tissues were found. In the series of pancreatic endocrine tumors reported by Heitz © 1992 hy Gustav Fischer Verlag, Stuttgart
et al.s, 40 patients showing abdominal mass, pain, jaundice, etc, did not suffer from hormonally induced symptoms. In 10 of them, an elevated serum level of pancreatic polypeptide (PP) was found, and the tumors in these cases were labelIed as PPoma because immunoreactive PP cells were also found in all of them. In order to probe into the endocrine nature of NFPETs, the clinical, pathological, immunohistochemical and ultrastructural characteristics of aseries of surgically resected NFPETs were studied and analyzed. Material and Methods From June 1968 to June 1990, 26 cases of NFPET were diagnosed and treated in PUMC Hospital. In one case, only a biopsy was taken during operation because of extensive liver metastasis. Surgical resections were performed in all the other 25 cases. Tumor tissues were fixed in 10 % neutral formalin, the biopsy material and 4-8 tissue blocks from each of the 25 resected tumors were embedded in paraffin. Routine paraffin sections were stained with hematoxylin-eosin (HE), and some were also 0344-0338/92/0188-0191$3.50/0
192 . Tong-hua Liu et al. Table 1. Working dilution and source of antibodies
Table 2. Mode of operation
Antibody
Dilution
Source
Mode of operation
anti-insulin (porcine) anti-glucagon anti-somatostatin anti-NSE anti-PP
1: 100 1:400 1:600 1: 1,000 1: 10,000
Simple extirpation of islet tumor
7
anti-neurotensin
1: 1,000
anti-VIP anti-hCG(alpha) anti-hCG(beta)
1: 1,000 1:600 1:600
Miles Yeda DAKO Patt DAKO Patt DAKO Patt Gift from Dr. Chance, Lilly Lab. USA Gift from Dr. Polak, Royal Postgraduate Med School, London Immuno Nuclear Corp. UCB-Bioproducts UCB-Bioproducts
No.of cases
Extirpation of islet tumor with: 1) Segmental resection of common bile duct, 1 choledochostomy 2) Segmental resection involving small intestine, 4 end to end anastomosis (1 case with splenectomy) Extirpation of pheochromocytoma concomitantly 4) T-tube drainage of common bile duct 5) Partial resection of portal vein, end to end portal vein anastomosis and superior mesenterlC
stained according to periodic acid/Schiff (PAS) procedure and/or with reticulum stain. For immunohistochemical study, 2 to 4 paraffin blocks from each of the 25 surgically resccted tumors and the paraffin block embedding the specimens from the biopsy case were cut into serial sections of 5 [! thick. Peroxidase antiperoxidase (PAP) technique was used for all primary antibodies except anti-insulin, for which the indirect immunoperoxidase method was employed. The immunohistochemical staining for tumors, positive and negative controls were all the same as previously reported 8 • All primary antibodies were incubated at 4°C overnight. The primary antibodies used, their dilution and sources are listed in Table 1. Fresh tumor tissue from 9 cases was fixed in 2.5 % cold glutaraldehyde, postfixed in 1 % osmium tetraoxide, embedded in Epon 618. Sections of 1 [! thick were stained with toluidine blue for light microscopy while ultrathin sections were stained with uranyl acetate and lead citrate and examined under H-600 transmission electron microscope.
Results Clinical Features
Among the 26 patients, 19 were female and 7 were male, giving a male to female ratio of 1: 2.7. Ages ranged from 12 to 73 years, with a mean of 33 years. The majority of female patients were young or middle-aged, being 12 to 49 years, averaging 24.6 years. The male patients were significantly older than the female ones, being 40 to 73 years, and 55.7 years on average. The clinical symptoms and signs were nonspecific. Abdominal mass and abdominal pain were most common; and GI bleeding, nausea vomiting, anorexia, fever and jaundice were less frequently found. One patient suffered from rupture of esophageal varicose vein due to portal hypertension. Another patient had a pheochromocytoma in the right adrenal (multiple endocrine neoplasm IV, MEN IV) in addition to the NFPET in the pancreas. Her chief complaints were paroxysmal dizziness, headache and palpitation. Surgical Management and Prognosis
Twenty-five patients were subjected to different kinds of operation (Table 2}, The tumor was malignant in 12 (46.2 %) of the 26 cases, with regionallymph-node and/or
artery graft Distal partial resection of tumor bearing pancreas (body and tail) 1) Without splenectomy 1 2) With splenectomy 4 3) Roux- Y pancreatico-enterostomy 1 Pancrcatico-duodenectomy
3
Laparotomy
1
liver metastasis as found during operation in 4 ca ses and retroperitoneal meta stasis in 1 case of them. Two tumors invaded the inferior vena cava and pancreatic vein. Follow-up observation showed that lymph-node, liver and/or abdominal metastasis developed in 3 patients during 3-7 postoperative years, and the tumor recurred in 1 case 9 years after operation. One tumor originating from the pancreatic head extended diffusely into the body and tail of the pancreas. Three patients died postoperatively, 9 patients were lost from follow-up, and the remaining 14 patients have been followed for from 2 months to 7 years, and found to be alive with or without tumors. Pathology
All tumors were solitary as demonstrated by careful examination, completely or partially encapsulated and clearly circumscribed. Some tumors had very thick and tough fibrous capsules. On cut surfaces, the tumors were greyish white in color, homogeneous, usually associated with areas of hemorrhage and/or necrosis (Fig. 1). Some tumors showed cystic change of different sizes. The largest diameter of the tumors ranged from 3.5 cm to 20 cm, with an average of 9.9 cm. Fourteen tumors (53.8 %) were located in the head of the pancreas, 2 (7.7 %) in the body, 5 (19.8 %) in the tail and 4 (15.4 %) in the body-tail. In the remaining one case . (3.8 %), the exact site of the tumor could not be identified. Histologically, tumor cells were similar to those of functioning pancreatic endocrine tumors in shape and size. They were polygonal, low columnar, small round or oval
Non-functioning Pancreati c Endocrine Tumors· 193
