Diagnostic challenge of glucagonoma: case report and literature review.

OBJECTIVE: To report the diagnostic difficulties encountered in a case of glucagonoma. METHODS: We provide a literature review and present the clinical findings, pertinent laboratory data, and results of related studies in a patient with a glucagonoma. RESULTS: A 54-year-old-man, with no relevant history of endocrine disorders, presented to the hospital with a 5-year history of recurrent stomatitis and glossitis, a more recent weight loss of 11.5 kg, and recurrent pruritic maculae on the scalp in conjunction with raised erythematous maculae in the scrotal region and perineum that gradually migrated to the distal extremities, becoming bullous and painful. The patient was hospitalized, and because of the dermatologic findings suggestive of necrolytic migratory erythema, the presence of a glucagonoma was suspected. His blood glucose levels were in the normal range. Glucagon levels were found to be elevated, and imaging studies confirmed the presence of an enlarged mass in the pancreatic tail, without evidence of extension to surrounding structures. Liver metastatic lesions were also excluded. After surgical removal of the tumor, the skin and oral mucosal lesions disappeared spontaneously. The histologic appearance and immunohistochemical staining results confirmed the diagnosis of a glucagonoma. Subsequently, all related symptoms resolved, and the glucagon levels normalized. CONCLUSION: The diagnosis of glucagonoma is often delayed. Clinicians should be aware of the unusual initial manifestations of this tumor and the potential for less than a full spectrum of the characteristic features of the glucagonoma syndrome.

Immunohistochemical localization of pancreatic secretory trypsin inhibitor in malignant pancreatic endocrine tumors.

Differentiation of benign from malignant pancreatic endocrine tumors by existing clinical, biochemical, histologic, and cytologic criteria is difficult. We immunohistochemically localized pancreatic secretory trypsin inhibitor (PSTI) in 28 pancreatic endocrine tumors (13 benign, 15 malignant). PSTI-immunoreactive cells were detected in nine endocrine tumors. Immunoreactivity in these tumors was detected in nearly all tumor cells in five cases, scattered cells in two cases, and a few cells in two cases. All positive cases were malignant, and eight were equal to or larger than 10 cm. Serum concentrations of PSTI were markedly elevated in the two patients so tested. PSTI may be a specific immunohistochemical marker for malignant pancreatic endocrine tumors.

Prohormone convertases (PC1/3 and PC2) in rat and human pancreas and islet cell tumors: subcellular immunohistochemical analysis.

Prohormone convertase 1/3 (PC1/3; also termed PC1 or PC3) and PC2 are enzymes that activate prohormones by cleaving the pairs of basic amino acids. This mechanism was initially inferred from the series of several endocrine and neuroendocrine precursor proteins, including proinsulin and proglucagon. To determine the cellular and subcellular distribution of PC1/3 and PC2 in the rat and human pancreas, immunohistochemistry was performed using polyclonal antisera against mouse PC1/3 (ST-28) and mouse PC2 (ST-29). These studies showed light and electron microscopic co-localization of insulin, PC1/3 and PC2, and the coexistence of glucagon and PC2 in the pancreatic islets. This tendency of colocalization was also depicted in one case of human insulinoma and three cases of human glucagonomas, as well as in rat insulinomas. In two cases of human insulinomas, incomplete processing of proinsulin was suggested by the absence of PC2. At the subcellular level in the rat pancreatic islet, the colocalization of PC1/3 and insulin, and that of PC2 and glucagon, were observed in the same secretory granules by immunoelectron microscopy and image analysis. These studies suggest that PC1/3 and PC2 can function with the specificities in the processing of proinsulin and proglucagon into their active forms, respectively, in the normal and neoplastic pancreatic islets.

An immunohistochemical study of glucagonoma conducted on the metastatic lymph nodes from a patient with recurrent metastatic glucagonoma: report of a case.

In this report, we briefly present the case of a 67-year-old woman who developed recurrent glucagonoma with lymph node metastasis. An immunohistochemical study of the metastatic tumor revealed immunoreactivity of glucagon and protein kinase C (PKC)-alpha, -beta, and -gamma in the tumor cells, two types of which were seen by electron microscopy. One type had abundant secretory granules and mitochondria, while the other had few granules and mitochondria. Some granules were similar to typical A cell granules and others were atypical. An immunoelectron microscopic demonstration revealed PKC-alpha, -beta, and -gamma immunostaining in the cytoplasm of all the tumor cells, while some secretory granules had PKC immunostaining, and others had no immunostaining. Thus, it appears that metastatic glucagonoma and its associated granules are composed of two types of mature and immature cells or granules. As immunoreactivity of PKC-alpha and -gamma was found in the tumor cells, but not in the normal A cells of the islets of Langerhans, the PKC subspecies alpha and gamma, which are not present in normal pancreatic A cells, may exist in human glucagonoma cells.

Proglucagon processing similar to normal islets in pancreatic alpha-like cell line derived from transgenic mouse tumor.

A pancreatic alpha-like cell line has been established from a glucagonoma arising in transgenic mice expressing a hybrid gene consisting of the rat glucagon-promoter sequence fused to the sequence encoding the SV40 T-antigen oncoprotein. The alpha-tumor cell 1 (alpha TC1) line maintained many characteristics of differentiated alpha-cells for greater than 40 passages in culture and expressed levels of glucagon mRNA 5- to 10-fold higher than those reported previously in rat and hamster islet cell lines. By radioimmunoassay, the cells synthesized considerable amounts of glucagon, glucagonlike peptide I (GLP-I), the major proglucagon fragment, and small amounts of unprocessed proglucagon but no free GLP-II. This distribution of peptides is similar to that found in extracts of rodent pancreases and is distinct from that seen with other islet cell lines, which process proglucagon in patterns more characteristic of intestinal cells. The GLP-I peptide in the alpha TC1 cell line was in the form of GLP-I-(1-37), which is inactive as a stimulator of insulin secretion, and not GLP-I-7-37) or -(7-36)-amide peptides, both of which are potent insulin secretagogues. The alpha TC1 cell line produced glucagon-related peptides in a relatively uniform pattern by immunocytochemistry, and electron microscopy revealed typical alpha-type (glucagon) secretory granules. Although the cell line was derived from an islet tumor producing only glucagon, the alpha TC1 cell line also produced insulin in addition to the glucagon peptides.(ABSTRACT TRUNCATED AT 250 WORDS)

Electron microscopic and immunoelectron microscopic demonstration of pancreatic polypeptide cells in glucagonoma: colocalization of pancreatic peptide and glucagon in single secretory granules.

We describe a case of pancreatic tumor in a 65-year-old woman with typical glucagonoma syndrome. Plasma glucagon (GL) and pancreatic polypeptide (PP) were markedly elevated up to 1404 and 1200 pg/ml, respectively. Histologic examination of the metastatic tumors in liver and lymph nodes showed endocrine-type tumors composed of GL-positive cells some of which coexpressed PP immunoreactivity. Electron microscopy revealed the tumor cells with single-type secretory granules similar to normal A cell granules. Double immunogold staining demonstrated both GL and PP immunoreactivities in the same secretory granules. Biologic and diagnostic significance of coexpression of PP and GL in a single secretory granules of pancreatic endocrine tumors is discussed briefly.

A malignant tumor of the pancreas producing glucagonoma syndrome: immunocytochemistry and ultrastructure of liver metastases and comparison with the primary tumor.

In this study, liver metastases from a patient with a pancreatic glucagonoma producing the syndrome have been investigated histologically, ultrastructurally, and immunocytochemically. A comparison has also been made between the metastases and the primary pancreatic tumor investigated in a parallel study. In the metastatic tissue, glucagon-, pancreatic polypeptide (PP)-, and somatostatin-containing cells were found together with a majority of cells without any immunoreactivity. Glucagon-positive cells were much more numerous than PP- and somatostatin-immunoreactive cells. As in the primary tumor, double immunogold staining of ultrathin sections demonstrated the co-existence of glucagon and PP immunoreactivities in most of the granulated cells, but PP immunolabeling was often faint, so that it probably could not be revealed by the PAP method in light microscopical sections. Such a finding, together with the histological and ultrastructural features, is consistent with an ontogenic and phylogenetic primitiveness of the metastatic cell population.

A malignant tumor of the pancreas producing glucagonoma syndrome: coexistence of glucagon and pancreatic polypeptide (PP) in the tumor cells.

A malignant tumor of the pancreas producing the glucagonoma syndrome and associated with high plasma levels of glucagon and pancreatic polypeptide was studied histologically, ultrastructurally, and immunocytochemically. The histologic and ultrastructural features were closely similar to those of previously reported malignant glucagonomas. However, immunolabeling with specific antisera revealed that, in addition to cells having only glucagon- or only pancreatic polypeptide-immunoreactivity, other cells were also present, showing a co-existence of both peptides. These findings indicate that the tumor contains a cell population with a phenotype similar to that of intestinal L-cells rather than to pancreatic A-cells.

Immunocytochemical patterns of islet cell tumors as defined by the monoclonal antibody HISL-19.

A series of 51 islet cell tumors removed from 28 patients was investigated immunohistochemically with the monoclonal antibody HISL-19. The antibody was produced after immunization of BALB/c mice with human islet cells and was found to react with a wide range of neuroendocrine and neural cells. All tumors presented positive immunoreaction showing various combinations of 2 basic patterns. The first pattern reflected the immunostaining of the secretory granules of the tumor cells. This "granular" staining was predominantly associated with benign neoplasms and with the tumoral production of glucagon and pancreatic polypeptide (PP), while it was absent or inconsistent in most insulin-secreting tumors. The second pattern consisted of focal immunoreactive aggregates located in a peri- (and, in polarized cells, supra-) nuclear position. This "cluster-type" staining showed a good morphologic and topographic correspondence with the Golgi apparatus of the cells of the same tumors, as shown by electron microscopy. The latter pattern was well represented in all types of islet cell tumors except those producing PP. Moreover, it was more apparent in less differentiated tumors in which the granular pattern was often absent or inconsistent. Cluster-type (but not granular) immunoreactivity was frequently found in some nonendocrine, nontumoral pancreatic structures, particularly in the epithelium of small ducts. However, the immunoreactive aggregates of nonendocrine cells were distinctly less prominent than those of endocrine cells. On the basis of a comparison with other immunohistochemical markers for neuroendocrine cells, it is concluded that the HISL-19 monoclonal antibody presents specific staining characteristics useful for the cytologic analysis of islet cell tumors.

Silent human pancreatic glucagonoma and "A" nesidioblastosis.

Surgical fragments of healthy and tumor-bearing pancreas from a patient with pancreatic tumor were studied by electron or light microscopy, histochemistry, and immunocytochemistry (human insulin, glucagon, somatostatin, gastrin, and bovine pancreatic polypeptide). Histological results were compared to those obtained by radioimmunoassay, both in tumor and serum. The tumor was identified as a glucagonoma because reactions for Grimelius' silver impregnation and immunoreaction with an antiserum against glucagon were positive and because a very high level of glucagon in the tumor was observed. Insulin, somatostatin, and gastrin levels remained normal, both in tumor and serum, but the glucagon level was normal in serum. Associated with this silent glucagonoma, an uncommon nesidioblastosis was also diagnosed with many A cells irregularly mixed with acinar cells, isolated or clustered in small groups. Acinar "intermediate" cells of "A" type were also observed. Such associative histopathological processes evoked possible development of an endocrine tumor from nesidioblastic-like tissue. Its embryogenic origin remained uncertain.

Secretory granules in benign and malignant glucagonomas of the pancreas.

Two cases of glucagonoma, one benign and the other malignant, was presented. Benign glucagonoma in a 29-year-old man with multiple endocrine neoplasia type 1 was composed largely of tumor cells with secretory granules ranging from 139 to 417 nm in diameter identical to A cell granules. There were a few tumor cells which contained no A cell granules but smaller granules of approximately 166 nm diameter similar to those of pancreatic polypeptide containing cells. Radioimmunoassay of the tumor extract showed 319 micrograms/g wet weight of glucagon and 0.72 microgram/g wet weight of pancreatic polypeptide. Malignant glucagonoma in a 34-year-old man was a massive tumor of 7 X 6 X 5 cm replacing the tail and body of the pancreas with multiple metastases. The tumor contained 0.2 microgram/g wet weight of glucagon and 0.065 microgram/g wet weight of vasoactive intestinal peptide. The electron microscopic examination revealed that the tumor cells had variable numbers of atypical secretory granules measuring 110 to 200 nm in diameter different from A cell granules. An analysis of plasma glucagon by the gel filtration technique showed the heterogeneity of glucagon molecules indicating the presence of large glucagon. Atypical secretory granules in malignant glucagonoma were considered to represent immature granules containing the precursor or intermediate of glucagon.

Glucagonomas. Ultrastructure and immunocytochemistry.

Pancreatic tumors harboring glucagon immunoreactive cells were found in four patients with diabetes mellitus. Alpha-cell (glucagon) granules were present in three tumors; pancreatic polypeptide (PP) immunoreactive cells were detected in two. In two patients the tumors were malignant and one of these had the glucagonoma syndrome; the other was a member of a family with MEN-type I syndrome. These cases illustrate three clinical subtypes of glucagonoma.

[A human pancreatic glucagonoma, ultrastructural, immunocytochemical and radioimmunological investigations (author's transl)]. / Etude ultrastructurale, immunocytochimique et radioimmunologique d'un glucagonome pancréatique humain.

The authors report a case of glucagonoma in a 52 years old man presenting a migratory necrolytic erythema. By conjugated means of arteriography and splenoportography with plasma glucagon assays the tumour was localized in the tail of the pancreas. Surgical excision was easy but hepatic metastases revealed the malignant nature of the tumor. This glucagonoma has been investigated by several approaches including electron microscopy, immunocytochemistry and radioimmunological techniques. The tumor contained scattered glucagon and pancreatic polypeptide immunoreactive cells; insuline, glucagon, somatostatin, pancreatic polypeptide, gastrin and VIP antisera gave negative results. Ultrastructurally, these cells showed atypical secretory granules different from A granules of the normal glucagon cell. Radio immunological determinations carried out after gel permeation chromatography of plasma revealed high molecular weight (4 000, 9 000, 14 000) immunoreactive glucagon peptides. They have been thought to be proglucagon forms which did not react with specific antiglucagon sera used in cytological studies. Reported data are consistent with the classification of this tumor in the category of glucagonoma with the "glucagonoma syndrome".