Calcitonin-secreting tumor of the pancreas

Insulinoma with Hyperprocalcitoninemia and Hypercalcitoninemia Showing Coexpression of Insulin and Calcitonin in Its Tumor Cells

Neuroendocrine neoplasms can produce multiple hormones that are released into the bloodstream, causing symptoms that vary depending on the type and quantity of hormones involved. We herein report a 63-year-old asymptomatic patient with pancreatic insulinoma who showed marked elevations in circulating calcitonin and procalcitonin levels that returned to normal following surgery. Immunohistochemical analyses confirmed the co-staining of calcitonin and insulin immunoreactivity in the tumor cells, suggesting a calcitonin-producing insulinoma. This insulinoma released calcitonin and a considerable amount of its precursor peptide, procalcitonin, resulting in both hyperprocalcitoninemia and hypercalcitoninemia.

Whole-exome sequencing of calcitonin-producing pancreatic neuroendocrine neoplasms indicates a unique molecular signature

Introduction

Calcitonin-producing pancreatic neuroendocrine neoplasms (CT-pNENs) are an extremely rare clinical entity, with approximately 60 cases reported worldwide. While CT-pNENs can mimic the clinical and diagnostic features of medullary thyroid carcinoma, their molecular profile is poorly understood.

Methods

Whole-exome sequencing (WES) was performed on tumor and corresponding serum samples of five patients with increased calcitonin serum levels and histologically validated calcitonin-positive CT-pNENs. cBioPortal analysis and DAVID gene enrichment analysis were performed to identify dysregulated candidate genes compared to control databases. Immunohistochemistry was used to detect the protein expression of MUC4 and MUC16 in CT-pNEN specimens.

Results

Mutated genes known in the literature in pNENs like MEN1 (35% of cases), ATRX (18-20% of cases) and PIK3CA (1.4% of cases) were identified in cases of CT-pNENs. New somatic SNVs in ATP4A, HES4, and CAV3 have not been described in CT- pNENs, yet. Pathogenic germline mutations in FGFR4 and DPYD were found in three of five cases. Mutations of CALCA (calcitonin) and the corresponding receptor CALCAR were found in all five tumor samples, but none of them resulted in protein sequelae or clinical relevance. All five tumor cases showed single nucleotide variations (SNVs) in MUC4, and four cases showed SNVs in MUC16, both of which were membrane-bound mucins. Immunohistochemistry showed protein expression of MUC4 in two cases and MUC16 in one case, and the liver metastasis of a third case was double positive for MUC4 and MUC16. The homologous recombination deficiency (HRD) score of all tumors was low.

Discussion

CT-pNENs have a unique molecular signature compared to other pNEN subtypes, specifically involving the FGFR4, DPYD, MUC4, MUC16 and the KRT family genes. However, a major limitation of our study was the relative small number of only five cases. Therefore, our WES data should be interpreted with caution and the mutation landscape in CT-pNENs needs to be verified by a larger number of patients. Further research is needed to explain differences in pathogenesis compared with other pNENs. In particular, multi-omics data such as RNASeq, methylation and whole genome sequencing could be informative.

Severe hypercalcemia due to metastatic pancreatic neuroendocrine tumor: a case report

BACKGROUND

Hypercalcemia of malignancy, as a paraneoplastic syndrome, is the most common metabolic disorder that accounts for 30% of malignancies and usually has a poor prognosis. Neuroendocrine tumors are uncommon and arise from neuroendocrine cells throughout the body. Actually, paraneoplastic hypercalcemia in neuroendocrine tumors is unusual and mostly associated with parathyroid hormone-related protein (PTHrP) secretion.

CASE PRESENTATION

We report a 51-year-old Iranian man who presented with nausea, vomiting, and significant weight loss for 1 month. Laboratory data revealed calcium of 26 mg/dl, accompanied by low level of PTH. Octreotide scan revealed a large donut-shaped octreotide avid lesion in the epigastric region at the right side of the mid-abdomen, with multiple varying size foci of abnormally increased radiotracer uptake in the epigastric region and both lobes of the liver. Endoscopic ultrasonography demonstrated a large heterogeneous mass lesion with irregular outline and good demarcation in the body of the pancreas with diffuse foci of calcification. Percutaneous biopsy of the liver mass demonstrated a well-differentiated neuroendocrine tumor (low grade) confirmed by immunohistochemistry with strongly positive chromogranin and synaptophysin stain. Hypercalcemia was treated with hydration, few sessions of hemodialysis, calcitonin, and denosumab injection. However, the patient developed symptomatic hypocalcemia. Oncology consultation led to prescription of long-acting octreotide 30 mg monthly and everolimus daily.

CONCLUSION

Pancreatic neuroendocrine tumor could lead to malignant hypercalcemia; secretion of PTHrP is the most common cause, and signs and symptoms are usually milder than paraneoplastic syndrome due to hematologic and solid tumor. Generally, survival is better; however, its treatment is challenging, and primary debulking surgery is often required. A team approach to management is important at all points.

A calcitonin-producing pancreatic neuroendocrine neoplasm treated with distal pancreatectomy a lengthy time after a left trisectionectomy for liver metastases: a case report

BACKGROUND

Calcitonin-producing pancreatic neuroendocrine neoplasms (PanNENs) are extremely rare. There have been no reports of a patient in whom liver metastases were the presenting finding, and a calcitonin-producing PanNEN was subsequently detected after a lengthy period.

CASE PRESENTATION

A 53-year-old man had diarrhea for several years. Computed tomography (CT) revealed multiple liver tumors. We performed a left trisectionectomy with a bile duct resection. The histologic examination showed neuroendocrine tumors G1. Immunohistochemistry was positive for calcitonin and the serum calcitonin level was elevated. Neuroendocrine neoplasms of hepatic origin are extremely rare, so a systemic exploration was performed, but no tumor was detected. CT showed a 4-mm calcification in the pancreatic body, but no contrast-enhanced mass was noted. Although the liver tumors were resected, the diarrhea and high serum calcitonin level persisted. Serial examinations were performed for 6 years, but no tumor was identified; however, 6.5 years after the hepatectomy the serum calcitonin level increased. CT showed a 10-mm contrast-enhanced mass in the calcified area of the pancreatic body. A distal pancreatectomy was performed. The histologic examination showed a neuroendocrine tumor G1, which mimicked the liver tumors. Immunohistochemistry was positive for calcitonin. After the distal pancreatectomy, the serum calcitonin level decreased and diarrhea resolved. The calcitonin-producing neuroendocrine neoplasm was considered the pancreatic primary and the hepatic tumors were metastases.

CONCLUSIONS

Calcitonin-producing PanNENs may be initially recognized as liver tumors and may become evident after a lengthy period, thus long-term observation is recommended. Aggressive surgeries may contribute to long-term survival.

What Lies behind Paraneoplastic Hypercalcemia Secondary to Well-Differentiated Neuroendocrine Neoplasms? A Systematic Review of the Literature

BACKGROUND

Neuroendocrine neoplasms (NEN) originate from neuroendocrine cells ubiquitously spread throughout the body. Hypercalcemia associated with cancer is the most common life-threatening metabolic disorder in patients with advanced stage cancer. Paraneoplastic hypercalcemia is more commonly associated with hematological malignancies, renal and breast carcinomas, and squamous cell carcinomas, but it has also been described in patients with well-differentiated NEN, where it often remains undiagnosed. Among its causes, systemic secretion of parathyroid hormone-related protein (PTHrP) and ectopic production of 1,25-dihydroxyvitamin D and parathyroid hormone (PTH) may be considered paraneoplastic causes of hypercalcemia. In order to clarify the diagnostic work up of paraneoplastic hypercalcemia in patients with NEN, we perform a systematic review, which is lacking in the literature.

METHODS

We performed a data search using MEDLINE and SCOPUS including papers from 1961 to 2021. We selected articles on paraneoplastic hypercalcemia associated with well-differentiated NEN.

RESULTS

The search led to the selection of 78 publications for a total of 114 patients. Pooled data showed that the most frequent primary tumor site associated with paraneoplastic hypercalcemia was pancreatic NEN, followed by Pheochromocytoma. In most cases, paraneoplastic hypercalcemia was caused by PTHrP production and secretion. In more than two thirds of cases, paraneoplastic hypercalcemia was present at the time of NEN diagnosis and, in metachronous cases, was related to local recurrence, distant metastasis development, or tumor progression. In most patients, a combination of therapeutic approaches was employed, and reduction of the tumor burden was essential to control the paraneoplastic syndrome.

DISCUSSION

The onset of hypercalcemia associated with cancer in patients with well-differentiated NEN represents a major clinical challenge. The complex clinical and therapeutical management of paraneoplastic hypercalcemia implies the need for a multidisciplinary approach, aimed at controlling the clinical syndrome and tumor growth.

Calcitonin-Producing Neuroendocrine Neoplasms of the Pancreas: Clinicopathological Study of 25 Cases and Review of the Literature

Increased levels of circulating calcitonin are a clue in the diagnosis of medullary thyroid carcinoma. However, hypercalcitoninemia can also be related to other pathological conditions, including pancreatic neuroendocrine neoplasms (PanNENs). Ectopic hormonal production is not unusual in both functioning and non-functioning PanNENs; however, little is known about the frequency of calcitonin expression in these neoplasms. The aims of this study were to assess the frequency of calcitonin immunoreactivity in PanNENs, independently from serum calcitonin levels, and to evaluate the clinicopathological and prognostic features of calcitonin-immunoreactive (Cal-IR) PanNENs, including a comparison with cases already reported in the literature. We screened 229 PanNENs for the immunohistochemical expression of calcitonin, including both functioning and non-functioning neoplasms, as well as both well-differentiated and poorly differentiated PanNENs. Both the clinicopathological data and the follow-up information were available and were compared with the immunohistochemical results. In addition, we reviewed the features of the calcitonin-producing PanNENs previously reported in the literature. Calcitonin was expressed in 25 of our 229 PanNENs (10.9%). Examples of well- and poorly differentiated, as well as both functioning and non-functioning PanNENs, were found to be calcitonin immunoreactive. Cal-IR PanNENs did not show any significant difference with the whole series of neoplasms included in the study, when the clinicopathological parameters were considered, except for a younger age at diagnosis and for a larger size of the tumor in non-functioning Cal-IR PanNENs. Taken together, our results show that calcitonin immunoreactivity is not an exceptional event in PanNENs. Furthermore, calcitonin expression does not identify a separate clinical entity, in contrast to other PanNENs with ectopic hormone production, such as adrenocorticotropic hormone (ACTH)-producing PanNENs, which show a distinctively more aggressive behavior.

Calcitonin-secreting pancreatic neuroendocrine tumors: a case report and review of the literature

OBJECTIVE

We report the presentation and novel therapy of a calcitonin-secreting pancreatic neuroendocrine tumor (PNET) and review the literature on this unusual neoplasm.

METHODS

We cite the history of a 38-year-old male who presented with fatigue, weight loss, and diarrhea and was found to have a pancreatic head mass on cross-sectional imaging, as well as liver metastases.

RESULTS

The patient's laboratory evaluation was notable for a >100-fold elevation of the peptide hormone calcitonin in serum. As calcitonin is typically secreted by thyroid C-cells, hypercalcitoninemia is considered a marker for medullary thyroid cancer (MTC) or C-cell hyperplasia, but it may be present in several physiologic or pathologic conditions or may be ectopically secreted in rare PNETs. An octreotide scan confirmed the presence of somatostatin (SST) receptors on the pancreatic mass and liver metastases, leading to the diagnosis of a calcitonin-secreting PNET. We initiated treatment with long-acting SST analogs and peptide receptor radionuclide therapy (90Yttrium-DOTATOC) and achieved disease regression while maintaining a high quality of life.

CONCLUSION

Functional PNETs that secrete calcitonin are exceedingly rare, but they are important to consider in the differential diagnosis of nonthyroid-mediated hypercalcitonemia or pancreatic tumors that present with diarrhea, as the management differs markedly from both MTC and other pancreatic malignancies.

Diarrhea caused by circulating agents

Circulating agents cause intestinal secretion or changes in motility with decreased intestinal transit time, resulting in secretory-type diarrhea. Secretory diarrhea as opposed to osmotic diarrhea is characterized by large-volume, watery stools, often more than 1 L per day; by persistence of diarrhea when patients fast; and by the fact that on analysis of stool-water, measured osmolarity is identical to that calculated from the electrolytes present. Although sodium plays the main role in water and electrolyte absorption, chloride is the major ion involved in secretion.

Calcitonin receptor-mediated CFTR activation in human intestinal epithelial cells

High levels of calcitonin (CT) observed in medullary thyroid carcinoma and other CT-secreting tumours cause severe diarrhoea. Previous studies have suggested that CT induces active chloride secretion. However, the involvement of CT receptor (CTR) and the molecular mechanisms underlying the modulation of intestinal electrolyte secreting intestinal epithelial cells have not been investigated. Therefore, current studies were undertaken to investigate the direct effects of CT on ion transport in intestinal epithelial cells. Real time quantitative RT-PCR and Western blot analysis demonstrated the expression of CTR in intestinal epithelial T84 cells. Exposure of T84 cells to CT from the basolateral but not from apical side significantly increased short circuit current (I_SC) in a dose-dependent manner that was blocked by 1 μM of CTR antagonist, CT8–32. CT-induced I_SC was blocked by replacing chloride in the bath solutions with equimolar gluconate and was significantly inhibited by the specific cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor, CFTR_127inh. Further, biotinylation studies showed that CT increased CFTR levels on the apical membrane. The presence of either the Ca²⁺ chelator, bis(2-aminophenoxy)ethane tetraacetic acid-acetoxymethyl (BAPTA-AM) ester or the protein kinase A (PKA) inhibitor, H89, significantly inhibited I_SC induced by CT (∼32–58% reduction). Response to CT was retained after permeabilization of the basolateral or the apical membranes of T84 cells with nystatin. In conclusion, the activation of CTR by CT induced chloride secretion across T84 monolayers via CFTR channel and the involvement of PKA- and Ca²⁺-dependent signalling pathways. These data elucidate the molecular mechanisms underlying CT-induced diarrhoea.

Calcitonin-secreting pancreatic endocrine tumors: systematic analysis of a rare tumor entity

OBJECTIVE

Pancreatic endocrine tumors (PETs) are characterized by the presence of hormone syndromes. Reports focusing on calcitonin-secreting PET (CTsPETs) are very rare. This study aimed to define a CTsPET-associated syndrome in regard to chemical, anatomical, and developmental aspects.

METHODS

A computerized MEDLINE search was conducted under the search items: "pancreatic endocrine tumor," "calcitonin," "neuroendocrine pancreatic tumor," and "pancreas." Results of clinical, histopathological, immunohistochemical, and biochemical assessments of all patients identified with CTsPET were registered and statistically analyzed.

RESULTS

Thirty-seven patients with CTsPET were identified. Mean serum calcitonin was elevated to the 89.2-fold of the upper reference value. Main symptoms were watery diarrhea (51.4%) and abdominal pain (35.1%). Most patients (59.5%) presented with metastatic spread at the time of diagnosis. Of all patients, 66.7% were alive after a mean follow-up of 28.9 months. Survival was higher in patients who underwent more aggressive surgical therapies independent from tumor sizes and in those with no metastases at the time of diagnosis.

CONCLUSIONS

High calcitonin levels should always raise suspicion of medullary thyroid carcinomas. However, when thyroid examination remains without pathological findings, a CTsPET should be excluded. An aggressive surgical approach even in cases with large primary tumor sizes may lead to a longer survival.

Pancreatic endocrine tumors

Pancreatic endocrine tumors have been steadily growing in incidence and prevalence during the last two decades, showing an incidence of 4-5/1,000,000 population. They represent a heterogeneous group with very varying tumor biology and prognosis. About half of the patients present clinical symptoms and syndromes related to substances released from the tumors (Zollinger-Ellison syndrome, insulinoma, glucagonoma, etc) and the other half are so-called nonfunctioning tumors mainly presenting with symptoms such as obstruction, jaundice, bleeding, and abdominal mass. Ten percent to 15% of the pancreatic endocrine tumors are part of an inherited syndrome such as multiple endocrine neoplasia type 1 (MEN-1), von Hippel-Lindau (VHL), neurofibromatosis, or tuberousclerosis. The diagnosis is based on histopathology demonstrating neuroendocrine features such as positive staining for chromogranin A and specific hormones such as gastrin, proinsulin, and glucagon. Moreover, the biochemical diagnosis includes measurement of chromogranins A and B or specific hormones such as gastrin, insulin, glucagon, and vasoactive intestinal polypeptide (VIP) in the circulation. In addition to standard localization procedures, radiology (computed tomography [CT] scan, magnetic resonance imaging [MRI], ultrasound [US]), somatostatin receptor scintigraphy, and most recently positron emission tomography with specific isotopes such as (11)C-5 hydroxytryptamin ((11)C-5-HTP), fluorodopa and (68)Ga-1,4,7,10-tetra-azacyclododecane-N,N',N″,N‴-tetra-acetic acid (DOTA)-octreotate are performed. Surgery is still one of the cornerstones in the management of pancreatic endocrine tumors, but curative surgery is rarely obtained in most cases because of metastatic disease. Debulking and other cytoreductive procedures might facilitate systemic treatment. Cytotoxic drugs, biological agents, such as somatostatin analogs, alpha interferons, mammalian target of rapamycin (mTOR) inhibitors and tyrosine kinase inhibitors are routinely used. Tumor-targeted radioactive treatment is available in many centres in Europe and is effective in patients with tumors that express high content of somatostatin receptors type 2 and 5. In the future, treatment will be based on tumor biology and molecular genetics with the aim of so-called personalized medicine.

Routine serum calcitonin measurement in the evaluation of thyroid nodules

Calcitonin (CT) is secreted mainly by parafollicular C cells. In normal subjects, serum CT (sCT) levels are low and barely detectable by commonly used assays. Increased sCT levels are highly suggestive of medullary thyroid carcinoma (MTC). Since the clinical manifestation of MTC is a thyroid nodule, either single or in the context of a multinodular goitre, the routine measurement of sCT in the evaluation of thyroid nodule(s) facilitates the diagnosis of MTC. sCT measurement is indeed more sensitive than cytology in finding MTC. There are two major benefits from this clinical practice: (a) the surgeon is alerted to the need to perform total thyroidectomy and central compartment lymphadenectomy, which is the minimal surgical treatment for MTC; and (b) the outcome of MTC is favourably affected because it is usually identified at a less advanced stage. However, other non-MTC causes of hypercalcitoninaemia and false sCT positivity do exist and must be recognized. The differential diagnosis is possible using previously validated assays against possible sources of interference, and performing stimulation tests with pentagastrin or, eventually, calcium infusion.

Multimodality management of a polyfunctional pancreatic endocrine carcinoma with markedly elevated serum vasoactive intestinal polypeptide and calcitonin levels

We present an unusual case of a 52-year-old woman with severe, uncontrollable, refractory diarrhea attributable to pancreatic endocrine carcinoma (ECA) with markedly elevated serum vasoactive intestinal polypeptide (VIP) and calcitonin levels. After initial correction of fluid and electrolyte abnormalities, the patient was treated with high-dose octreotide. Shortly thereafter, due to the intractable nature of her diarrhea, she underwent cytoreductive hepatic surgery. The pancreatosplenectomy specimen showed a poorly differentiated ECA of the distal pancreas, immunoreactive for synaptophysin, CD56, and S100 protein, with morphologically similar hepatic and lymph node metastases. Postoperatively, her diarrhea improved, along with decline in serum VIP and calcitonin levels. Systemic chemotherapy with etoposide and cisplatin did not result in any radiographic and biochemical improvement. Having radiologically stable disease with depot-octreotide and short-acting octreotide (Sandostatin), she was subjected to peptide receptor radiotherapy with [177Lu-DOTA0,Tyr]octreotate (LuTate) that resulted in marked clinical and biochemical improvement, along with dramatic reduction in the number and size of hepatic metastases. In summary, this is a unique case of metastatic VIP- and calcitonin-secreting pancreatic ECA with dramatic sustained clinical, biochemical, and objective tumor response to peptide receptor radionuclide therapy.

Digestive calcitonin-secreting tumors of the foregut: comparison with non-calcitonin-secreting tumors

OBJECTIVES

Digestive calcitonin-secreting endocrine tumors are very rare lesions of the foregut. This study was undertaken to compare the characteristics and the prognosis of these tumors and those of non-calcitonin-secreting endocrine tumors.

METHODS

All patients with a digestive endocrine tumor of the foregut followed up in Reims University Hospital and whose serum calcitonin levels were determined between 1988 and 2004 were included. Clinical and tumor characteristics of calcitonin-positive and calcitonin-negative patients were compared.

RESULTS

Thirty-two patients were included. Among the five (15.6%) with high calcitonin levels (median: 340 pg/ml, range: 42-7460 pg/ml), only one tumor was functioning (diarrhea). Significant differences between patients with positive and negative calcitonin levels were, respectively: liver metastases [5 (100%) versus 11 (40.7%); P=0.04], type according to the World Health Organization 2000 histological classification [notably 4 (80%) versus 3 (12.5%) poorly differentiated endocrine carcinomas; P=0.02] and Ki67 proliferation index [median: 25% (range: 20-30%) versus 7% (0-80%); P=0.03]. The only calcitonin-positive well-differentiated endocrine carcinoma had a high proliferation index (30%). Survival also differed significantly (P=0.001), as all calcitonin-positive patients died, with a median survival of 22.6 months (range: 1.2-27.2 months), versus five (18.5%) calcitonin-negative patients. Median follow-up period for the latter was 42.3 months (range: 3.4-208 months).

CONCLUSIONS

The secretion of calcitonin appears predictive of a poor prognosis. Digestive endocrine calcitonin-secreting tumors correspond histopathologically to poorly differentiated or well-differentiated carcinomas with high proliferation indexes.