Pancreatic endocrine tumors: an update

Fine-Needle Aspiration Cytology in the Diagnosis of Pancreatic Neuroendocrine Tumors: A Single-Center Experience of 25 Cases

OBJECTIVE

Pancreatic neuroendocrine tumors (Pan NETs) are rare but are being increasingly diagnosed. The objective of this retrospective study was to share our experience of fine-needle aspiration (FNA), including endoscopic ultrasound-guided FNA with rapid on-site evaluation (ROSE), with the use of immunohistochemical (IHC) markers in the diagnosis of Pan NET.

STUDY DESIGN

A total of 25 cases of Pan NET diagnosed on pancreatic FNA between 2008 and 2013 were identified from our hospital database. Clinical history, radiology, cytomorphological features, and IHC performed were reviewed.

RESULTS

The mean age of our patient group was 52 years; 15/25 were male. Most presented with abdominal pain and the majority of the lesions were in the pancreatic body, the largest being 14 cm in size. Based on the 2010 World Health Organization criteria, cases were further graded as follows: 21 cases were grade 1, 2 cases were grade 2 and 2 cases were grade 3. Proliferation marker Ki-67 was utilized in 6 cases for definitive grading. Of the 25 cases, 23 were diagnosed as nonfunctional while 2 were functional; 1 patient had MEN-1 syndrome and 1 had von Recklinghausen's syndrome.

CONCLUSIONS

Our data suggests that FNA, with ROSE and IHC markers, is highly sensitive and specific for diagnosing Pan NET.

Endoscopic ultrasound-guided fine-needle aspiration diagnosis of clear-cell pancreatic endocrine neoplasm in a patient with von Hippel-Lindau disease: a case report

The cytologic findings of a clear-cell pancreatic endocrine neoplasm (PEN) diagnosed by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) occurring in a 29-year-old man with von Hippel-Lindau (VHL) syndrome are described. Imaging studies showed multiple pancreatic masses and cysts, a single liver lesion, and pulmonary and renal cysts. Cytologic features of this clear-cell PEN included the presence of large sheets and rounded clusters of polygonal neoplastic cells with relatively abundant cytoplasm containing numerous, small, sharply-demarcated vacuoles that occasionally indented nuclei and gave the cells a "frothy" appearance. Mild anisonucleosis was present and nucleoli were visible. Rare single cells and stripped nuclei were seen. Small vessels transgressed tumor cell sheets. These cytologic findings are distinct from those of typical endocrine neoplasms, and bear resemblance to the cytologic features of renal cell carcinoma metastatic to the pancreas. To the best of our knowledge, this is the first detailed report of the EUS-FNA cytologic findings of a clear-cell PEN associated with VHL syndrome. We believe that the distinctive and characteristic cytologic features, together with immunohistochemical studies, can allow a preoperative cytologic diagnosis of this highly unusual pancreatic lesion and avoid possible confusion with other clear-cell neoplasms in the pancreas, particularly metastatic renal cell carcinoma.

Endoscopic ultrasound-guided fine-needle aspiration cytology of pancreatic neuroendocrine tumors: a study of 48 cases

BACKGROUND

Neuroendocrine tumors (NETs) of the pancreas are relatively uncommon tumors. The objective of this report was to describe the cytopathologic and immunocytochemical features of NETs obtained by endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA).

METHODS

Forty-eight patients who were diagnosed with pancreatic NETs based on EUS-guided FNA were studied retrospectively (from 2002 to 2007). Clinical data, EUS findings, cytopathologic features, and immunocytochemical stains were reviewed for this study. The final histopathologic diagnosis from each patient also was available for comparison.

RESULTS

Forty-eight patients (28 men and 20 women) who ranged in age from 16 years to 86 years were selected and had the following clinical findings: solid or multiple pancreatic masses diagnosed by computed tomography or magnetic resonance imaging studies; simultaneous, suspicious, metastatic masses in the liver, mediastinum, and/or lung; hypoglycemia; multiple endocrine neoplasia type 1 syndrome; von Hippel-Lindau syndrome; and primary NET of the small bowel. EUS findings revealed solid or multiple masses in the pancreatic head/uncinate, or in the pancreatic body/tail, or simultaneously in the pancreatic head/uncinate and body/tail. Cytologically, 40 patients were diagnosed with NETs (histopathogically confirmed), and 8 patients had findings that were suspicious of NETs (2 patients had false-positive results, and 6 patients had histopathologically confirmed NETs). The most helpful cytologic findings for the diagnosis of NET were a richly cellular sample with a monotonous, poorly cohesive population of small or medium-sized cells with granular chromatin (salt and pepper) and plasmacytoid morphology. Immunocytochemistry confirmed the neuroendocrine origin of tumors in 40 patients (material for immunocytochemistry was inadequate in 8 patients).

CONCLUSIONS

The current results indicated that EUS-guided FNA is a useful method for the diagnosis of pancreatic NETs. Cytopathologic examination in coordination with immunocytochemistry can provide an accurate diagnosis in most patients.

Application of immunohistochemistry to liver and gastrointestinal neoplasms: liver, stomach, colon, and pancreas

CONTEXT

Immunohistochemistry has become an integral component of the practice of pathology. Newer antibodies allow for increasingly precise diagnoses for tumors that previously could not be easily identified. Recently, immunohistochemical evaluations have begun to allow pathologists to actively assist in determining prognosis and even in selecting therapies.

OBJECTIVE

To summarize the usefulness of currently available immunostains for the study of liver and gastrointestinal system neoplasms and to make recommendations for panels of immunostains that can be particularly helpful.

DATA SOURCES

Information has been collected from recent literature as well as from personal experience and practice.

CONCLUSIONS

Many immunostains are now available for the practicing pathologist that allow for increasing accuracy in diagnosis of liver and gastrointestinal tract neoplasms. Panels of immunostains can be used to differentiate between various tumors and also to identify site of origin in the case of a metastatic neoplasm. Immunostains that allow for prognostic determinations and for guidance in the selection of chemotherapeutic agents can also be used by pathologists to assist in the management of patients with malignant tumors affecting the liver and gastrointestinal tract.

Extensive acrochordons and pancreatic islet-cell tumors in tuberous sclerosis associated with TSC2 mutations

Acrochordons are frequently encountered benign skin lesions that may occasionally represent underlying pathology. Pancreatic islet-cell tumors are rare neoplasms and few cases have been described in patients with tuberous sclerosis complex (TSC). A 39-year-old man presenting in acute renal failure was referred to us for further diagnostic evaluation of coincidentally noted dysmorphic features. Physical examination revealed over 1,000 acrochordons in addition to findings meeting criteria for TSC. The diagnosis was confirmed by disclosure of mutation in the TSC2 gene. Further evaluation revealed pancreatic islet cell tumors. Acrochordons are a common skin lesion, but when presenting in an atypical manner or unusual number may be a sign of TSC and underlying occult pathology thereby warranting evaluation of TSC2. Additionally, mutations in TSC2 gene may be a risk factor for developing pancreatic islet-cell tumors.

Review of endoscopic ultrasound-guided fine-needle aspiration cytology

This review, based on the Hennepin County Medical Center experience and review of the literature, vastly covers the up-to-date role of endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (FNA) in evaluating tumorous lesions of the gastrointestinal tract and adjacent organs. Emphasis is given to the tumoral and nodal staging of esophageal, pulmonary, and pancreatic cancer. This review also discusses technical, pathological, and gastroenterologic aspects and the role of the pathologist and endosonographer in the evaluation of these lesions, as well as the corresponding FNA cytology and differential diagnosis.

Molecular Evidence for Independent Origin of Multifocal Neuroendocrine Tumors of the Enteropancreatic Axis

Neuroendocrine tumors of the enteropancreatic axis are often multifocal. We have investigated whether multifocal intestinal carcinoid tumors and multifocal pancreatic endocrine tumors arise independently or whether they originate from a single clone with subsequent intramural or intrapancreatic spread. Twenty-four cases, including 16 multifocal intestinal carcinoid tumors and eight multifocal pancreatic endocrine tumors, were studied. Genomic DNA samples were prepared from 72 distinct tumor nodules using laser capture microdissection. Loss of heterozygosity (LOH) assays were done using markers for putative tumor suppressor genes located on chromosomes 9p21 (p16), 11q13 (MEN1), 11q23 (SDHD), 16q21, 18q21, and 18q22-23. In addition, X chromosome inactivation analysis was done on the tumors from eight female patients. Twenty-two of 24 (92%) cases showed allelic loss in at least one tumor focus, including 15 of 16 (94%) cases of multifocal carcinoid tumors and 7 of 8 (88%) cases of multifocal pancreatic endocrine tumors. Eleven of 24 (46%) cases exhibited a different LOH pattern for each tumor. Additionally, 9 of 24 (38%) cases showed different LOH patterns among some of the coexisting tumors, whereas other coexisting tumors displayed the same allelic loss pattern. Two of 24 (8%) cases showed the same LOH pattern in every individual tumor. X chromosome inactivation analysis showed a discordant pattern of nonrandom X chromosome inactivation in two of six informative cases and concordant pattern of nonrandom X chromosome inactivation in the four remaining informative cases. Our data suggest that some multifocal neuroendocrine tumors of the enteropancreatic axis arise independently, whereas others originate as a single clone with subsequent local and discontinuous metastasis.

Endoscopic ultrasound-guided fine needle aspiration cytology of pancreatic neuroendocrine tumours: cytomorphological and immunocytochemical evaluation

OBJECTIVES

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) is increasingly used in preoperative localization and diagnosis of pancreatic neoplasms including neuroendocrine tumours (NETs). The objective of the present study was to identify the cytological features of pancreatic NETs obtained by EUS-FNA.

METHODS

The study group consisted of nine cases of pancreatic tumours correctly diagnosed or strongly suggestive of NETs based on EUS-FNA. Cytological smears were retrospectively reviewed. The clinical data and immunocytochemical stains applied to the cell block preparations were also reviewed and examined.

RESULTS

All cases except one showed characteristic cytomorphological features sufficient for their recognition and separation from pancreatic adenocarcinoma and other lesions. The most helpful cytological features that facilitated the cytological diagnosis of NET were a richly cellular aspirate with a monotonous, poorly cohesive population of small cells with a speckled or dusty chromatin pattern and plasmacytoid morphology. The neuroendocrine differentiation of these tumours was further confirmed by immunocytochemistry.

CONCLUSION

EUS-FNA is a valuable method in the recognition of pancreatic NETs. By adherence to the characteristic cytomorphological criteria of pancreatic NET together with collection of suitable material for ancillary immunocytochemical stains, cytopathologists could reach a correct diagnosis in most instances.

Lipid-Rich Variant of Pancreatic Endocrine Neoplasms

Most pancreatic endocrine neoplasms (PENs) show characteristic and well-recognized endocrine morphology; however, a lipid-rich pattern, which can present a diagnostic problem in biopsies, has been reported, mostly as individual cases. Some have been included in descriptions of the rare clear-cell variant associated with von Hippel-Lindau (VHL) syndrome. The histogenesis, clinicopathologic characteristics, and significance of this lipid-rich pattern have not been unraveled. In this study, 11 PENs exhibiting foamy, microvesicular cytoplasm were analyzed. In some cases, the nuclei were distorted by the vesicles, and the usual endocrine chromatin pattern was not evident. The growth pattern was relatively diffuse, with vague compartmentalization of the cells by a delicate vasculature; prominent nesting was noted in only 4 cases. Pathology reports indicated substantial diagnostic challenge in these cases; on biopsies, 1 case was originally diagnosed as adrenal cortical carcinoma, another as renal cell carcinoma, a third as solid-pseudopapillary tumor, and a fourth had a fine needle aspiration cytologic diagnosis of adenocarcinoma. All cases were chromogranin and synaptophysin positive. Electron microscopy in 3 cases confirmed the cytoplasmic vesicles to be lipid vacuoles. Neurosecretory granules were also evident. Clinically, as in conventional PENs, there appeared to be two distinct subsets: Two cases were familial or functional/syndromic (1 with VHL and the other with MEN-1 and glucagonoma syndrome) and occurred in younger adults (ages 41 and 47 years); the majority (n = 9) were nonfunctional/nonsyndromic and nonfamilial. The latter group was mostly represented by elderly males (mean age: 65 vs. 58 years in conventional sporadic PENs). Immunohistochemically, markers implicated in VHL-associated neoplasia, including HIF-1alpha, inhibin, and Melan-A (in clear-cell PENs) and MUC6 (in serous cystadenomas) were mostly negative in lipid-rich PENs (1 of 10, 1 of 10, 0 of 10 and 0 of 10, respectively). In conclusion, the lipid-rich pattern, reminiscent of adrenal cortical cells, represents a distinct subset of PENs. It presents a diagnostic challenge for surgical pathologists, especially in biopsies. EM supports the name lipid-rich for this variant. The findings suggest that the pathogenesis of lipid-rich tumors may be different from the VHL-associated clear-cell variants of PENs.

Cytologic diagnosis of pancreatic endocrine tumors by endoscopic ultrasound-guided fine-needle aspiration: A review

Precise localization and diagnosis of pancreatic endocrine tumors (PETs) is important, because pancreatic PETs have different clinical and biological behavior and treatment modalities than do exocrine pancreatic tumors. In contrast to the much more common exocrine adenocarcinomas, cytologic studies of PET are relatively rare and many cytopathologists lack experience with the cytomorphologic features of these tumors.During the last 10 yr, endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) has matured into an accurate, highly sensitive, and cost-effective modality for the preoperative localization of pancreatic PETs. This has resulted in an increased number of PETs first sampled as cytology specimens. This manuscript focuses on the cytomorphologic features most suggestive of pancreatic PETs, differential diagnosis, and diagnostic pitfalls of PETs. The technical development of EUS-guided FNA and the ancillary studies for pancreatic PETs are also reviewed. The data summarized in this review indicate that EUS-FNA is a valuable method in the recognition of pancreatic PETs and in most cases cytopathologists could reach a correct diagnosis of these tumors, including their hormone producing capability on aspirated cytologic material.