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

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.

European Neuroendocrine Tumor Society 2023 guidance paper for functioning pancreatic neuroendocrine tumour syndromes

This ENETS guidance paper aims to provide practical advice to clinicians for the diagnosis, treatment and follow-up of functioning syndromes in pancreatic neuroendocrine tumours (NET). A NET-associated functioning syndrome is defined by the presence of a clinical syndrome combined with biochemical evidence of inappropriately elevated hormonal levels. Different hormonal syndromes can be encountered in pancreatic NET patients, including insulinoma, gastrinoma as well as the rare glucagonoma, VIPoma, ACTHoma, PTHrPoma, carcinoid syndrome, calcitoninoma, GHRHoma and somatostatinoma. The recommendations provided in this paper focus on the biochemical, genetic and imaging work-up as well as therapeutic management of the individual hormonal syndromes in well-differentiated, grade 1-3, functioning NET with the primary tumour originating in the pancreas, and for specific subtypes also in the duodenum.

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.

Calcitonin-secreting pancreatic neuroendocrine tumor in a patient with elevated thyroid fine-needle aspirate calcitonin washout: A case report and review of the literature

We report the unique case of a patient with previously proven non-functional PanNET and Graves' disease with thyroid nodules. The patient had elevated intranodular calcitonin, but no MTC or c-cell hyperplasia on thyroidectomy. They were found to have calcitonin secreting PanNET. This case presents a false-positive intranodular calcitonin.

Persistence of Elevated Procalcitonin in a Patient with Coronavirus Disease 2019 Uncovered a Diagnosis of Medullary Thyroid Carcinoma

Objective

During the ongoing coronavirus disease 2019 pandemic, procalcitonin (PCT) levels have proven useful in assisting clinicians to diagnose bacterial superinfection. However, in the absence of signs of infection or at the resolution thereof, inappropriately and persistently high PCT levels may suggest and reveal the presence of other pathologies. We report a patient with severe acute respiratory syndrome coronavirus 2 pneumonia with initially elevated PCT levels that persisted during recovery, prompting the diagnosis of medullary thyroid carcinoma (MTC).

Methods

A 43-year-old man presented with a 2-day history of fever, sneezing, sore throat, and dry cough. His PCT was 94 ng/mL (normal value, 0.00-0.10 ng/mL), and he was positive for severe acute respiratory syndrome coronavirus 2 RNA.

Results

Empirical antibiotic therapy was administered for 7 days, but despite a clinical improvement, serum PCT remained high (84 ng/mL). Serum calcitonin (CTN) was 2120 pg/mL (normal, ≤12 pg/mL). Cytologic examination of thyroid nodules and CTN measurement of the aspiration needle washout confirmed MTC. The patient underwent total thyroidectomy with bilateral cervical lymph node dissection. Lowered CTN (986 pg/mL) and PCT (16 ng/mL) levels were observed 48 hours after surgery. A close follow-up was planned following the results of RET gene analysis.

Conclusion

PCT can be a useful biochemical marker of MTC suspicion in patients with inflammatory conditions and persistently elevated PCT, even after resolution. In our case, high levels of PCT in a patient with coronavirus disease 2019 pneumonia without signs of bacterial infection led to MTC diagnosis.

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.

Detection of Biosynthetic Precursors, Discovery of Glycosylated Forms, and Homeostasis of Calcitonin in Human Cancer Cells

The peptide hormone calcitonin is intimately connected with human cancer development and proliferation. Its biosynthesis is reasoned to proceed via glycine-, α-hydroxyglycine-, glycyllysine-, and glycyllysyllysine-extended precursors; however, as a result of the limitations of current analytical methods, until now, there has been no procedure capable of detecting these individual species in cell or tissue samples. Therefore, their presence and dynamics in cancer had not been established. Here, we report the first methodology for the separation, detection, and quantification of calcitonin and each of its precursors in human cancer cells. We also report the discovery and characterization of O-glycosylated calcitonin and its analogous biosynthetic precursors. Through direct and simultaneous analysis of the glycosylated and nonglycosylated species, we interrogate the hormone biosynthesis. This shows that the cellular calcitonin level is maintained to mitigate effects of biosynthetic enzyme inhibitors that substantially change the proportions of calcitonin-related species released into the culture medium.

Unusual Cushing's Syndrome and Hypercalcitoninaemia due to a Small Cell Prostate Carcinoma

A 75-year-old man was hospitalized because of severe hypokalaemia due to ACTH dependent Cushing's syndrome. Total body computed tomography (TBCT) and 68 Gallium DOTATATE PET/CT localized a voluminous prostate tumour. A subsequent transurethral prostate biopsy documented a small cell carcinoma positive for ACTH and calcitonin and negative for prostatic specific antigen (PSA) at immunocytochemical study; serum prostatic specific antigen (PSA) was normal. Despite medical treatments, Cushing's syndrome was not controlled and the patient's clinical condition progressively worsened. Surgical resection was excluded; the patient underwent a cycle of chemotherapy followed by febrile neutropenia and fatal intestinal perforation. This case report describes a rare case of Cushing's syndrome and hypercalcitoninaemia due to a small cell carcinoma of the prostate, a rare tumour with very few therapeutic options and negative prognosis.

pNET co-secreting GHRH and calcitonin: ex vivo hormonal studies in human pituitary cells

Acromegaly due to ectopic GHRH secretion from a neuroendocrine tumor (NET) is rare and comprises <1% of all acromegaly cases. Herein we present a 57-year-old woman with clinical and biochemical features of acromegaly and a 6 cm pancreatic NET (pNET), secreting GHRH and calcitonin. Following surgical resection of the pancreatic tumor, IGF1, GH and calcitonin normalized, and the clinical features of acromegaly improved. In vitro studies confirmed that the tumor secreted large amounts of both GHRH and calcitonin, and incubation of pNET culture-derived conditioned media stimulated GH release from a cultured human pituitary adenoma. This is a unique case of pNET secreting both GHRH and calcitonin. The ability of the pNET-derived medium to stimulate in vitro GH release from a human pituitary-cell culture, combined with the clinical and hormonal remission following tumor resection, confirmed the ectopic source of acromegaly in this patient.

Extrathyroidal Calcitonin Secreting Tumors: Pancreatic Neuroendocrine Tumors in Patients With Multinodular Goiter: Two Case Reports

Calcitonin is the hallmark of medullary thyroid carcinoma. However, extrathyroidal neuroendocrine tumors can also release calcitonin.We report 2 cases of calcitonin-secreting pancreatic tumors found in asymptomatic patients with thyroid nodules referred to our center within 11 months.Case 1: A man initially referred for thyroid nodule characterization was found to have hypercalcitoninemia (>200 pg/mL) during non-neoplastic fine-needle aspiration.Case 2: A woman evaluated for liver metastasis was found to have hypercalcitoninemia and multinodular goiter.Our research emphasizes that marked hypercalcitoninemia in the presence of thyroid nodules is not necessarily due to medullary thyroid carcinoma; awareness of this could avoid unnecessary thyroidectomy. The lack of specific symptoms related to hypercalcitoninemia may be the reason that the prevalence of calcitonin-secreting pancreatic tumors is underestimated.