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

Endocrine paraneoplastic syndromes in lung cancer: A call for clinical vigilance (Review)

Endocrine paraneoplastic syndromes (PNS) are uncommon but clinically impactful manifestations associated with malignancies, particularly lung cancer, most notably small-cell lung cancer. These syndromes arise from ectopic hormone production by malignant cells, causing systemic effects that are independent of direct tumor invasion or metastasis. Their presentation often precedes or signals recurrence of the primary cancer, underscoring the importance of early recognition and targeted intervention. Common endocrine PNS in lung cancer include syndrome of inappropriate antidiuretic hormone secretion, hypercalcemia, Cushing syndrome, carcinoid syndrome, and other hormonal imbalances such as non-islet cell tumor hypoglycemia, gynecomastia and acromegaly. The pathophysiology of these conditions involves ectopic secretion of bioactive substances such as hormones and cytokines, leading to diverse clinical manifestations. Accurate diagnosis necessitates a combination of biochemical assessments, imaging modalities, and histopathological evaluations to differentiate paraneoplastic processes from primary endocrine disorders. Management strategies emphasize treating the underlying malignancy, often through chemotherapy, radiotherapy, or surgical intervention, alongside symptomatic therapies tailored to the specific endocrine abnormality. Multidisciplinary care is critical for optimizing outcomes and enhancing patients' quality of life. The current review highlights the need for heightened clinical vigilance and a systematic approach to diagnosing and managing endocrine PNS in lung cancer. By fostering early detection and comprehensive management, clinicians can significantly improve prognostic outcomes for affected individuals.

Functioning neuroendocrine tumors (NET): Minimum requirements for a NET specialist

INTRODUCTION AND AIMS

Functioning neuroendocrine tumors (f-NETs) represent a minority of all NETs, however their management is challenging due to the impact on patients' survival and quality of life. In addition to f-NETs, paraneoplastic syndromes (PNS) are due to substances that are not related to the primary anatomical site, they can develop in different phases of NETs evolution, and might complicate the patient's clinical course. Dedicated guidelines are still scanty. We aim to review available literature on f-NETs to propose a useful tool for clinicians in order to improve the diagnostic process and the management.

METHODS

Narrative review focused on f-NETs.

RESULTS

The most common f-NETs include insulinomas, gastrinomas and carcinoid syndrome (CS)- associated NETs. Symptoms related to hormone production may overlap with other common endocrine and gastrointestinal disorders, highlighting the pivotal role of multidisciplinary management. Somatostatin analogs (SSAs) represent the gold standard first-line treatment of most f-NETs, often followed by or combined with other treatments (surgery, liver-directed therapies, targeted therapies, peptide receptor radionuclide therapy). Paraneoplastic syndromes can develop in different phases of NET evolution and might complicate the patient's clinical course and response to therapy.

CONCLUSIONS

The management of hormonal syndromes is challenging and must be based on the multidisciplinary approach. Herein, we pointed out the minimal requirements for a NET specialist in the diagnosis and treatment of f-NETs. Efforts should be made to improve the awareness of functioning forms, to understand their pathogenesis and to improve their management.

Hypercalcemia due to PTHrp producing pancreas NET: A case report

INTRODUCTION

Secretion of parathormone related peptide (PTHrp) is the most common cause of tumor-associated hypercalcemia. This occurs most often in squamous cell carcinomas in the ear nose and throat, bronchial and breast carcinomas. We report a rare case of a PTHrp-producing pancreatic neuroendocrine tumor (pNET) and provide a brief review of the literature.

CASE PRESENTATION

A 68-year-old female patient with epigastric pain and weight loss was diagnosed with a 11 × 8 × 9 cm tumor in the pancreatic body with infiltration of the splenic vein and consecutive portal vein thrombosis without evidence of distant metastases. An endosonographic fine needle aspiration revealed a neuroendocrine tumor G2 (Ki-67 3 %). Laboratory analyses showed an asymptomatic hypercalcemia and elevated PTHrp. Distal splenopancreatectomy, left adrenalectomy, thrombectomy of the portal vein, cholecystectomy and partial resection of the left renal vein was performed. Histopathologic examination showed a PTHrp-producing NET of the pancreas G2, pT4 pN0 M0 L0 V2 Pn0 R0. Postoperatively serum levels of PTHrp and calcium dropped to normal values.

DISCUSSION

Up to date only 83 cases of PTHrp producing pNETs have been reported in the English literature. Frequently, as in the reported patient, locally advanced or already distantly metastasized tumors were present. In addition to initial drug control of hypercalcemia, surgical treatment in case of R0 resection offers long-term symptom control and should be performed, when possible.

CONCLUSION

In case of a pancreatic tumor and the simultaneous occurrence of hypercalcemia, the determination of PTHrp should be considered. Surgical resection remains the only curative therapy.

Survival Outcomes in Malignancy-related Hypercalcemia: A Tertiary Care Single-center Experience

Introduction

Malignancy-related hypercalcemia is commonly observed in patients with advanced stages of cancer. It is intricately linked with an unfavorable prognosis among oncology patients. This study aimed to evaluate survival outcomes among individuals diagnosed with hypercalcemia associated with malignancy.

Materials and Methods

This retrospective analysis of 173 cancer patients with hypercalcemia who sought treatment at Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan, between July 2019 and June 2020. This cohort of patients underwent a longitudinal follow-up for 2.5 years. To assess survival outcomes, the Kaplan-Meier tool was used to construct survival curves and estimate the survival probability over time. The significance of potential survival factors was evaluated using the log-rank test.

Results

All patients exhibited elevated levels of calcium. At admission, the cohort demonstrated varying degrees of hypercalcemia severity attributable to malignancy: Mild hypercalcemia was observed in approximately 61.3% of patients, moderate hypercalcemia in 23.7%, and severe hypercalcemia in 15% of cases. Among the total sample, most patients were female (54.9%), with a median age of 54. The primary tumor site most frequently observed was in cases of breast cancer (35.3%), wherein the prevalent histological subtype was lobular/ductal invasive carcinoma (34.1%). Most of the patients (93.6%) had an Eastern Cooperative Oncology Group (ECOG) performance status (ECOG) >1. In addition, the median overall survival for patients diagnosed with hypercalcemia was 51 days. Notably, there was a significant association between survival factors, including the primary site of malignancy (P = 0.001), bone metastasis (P = 0.04), severity and symptoms of hypercalcemia (P = 0.001), altered mental state (P = 0.001), albumin levels (P = 0.001), and ECOG (P = 0.001).

Conclusion

Malignancy-related hypercalcemia in patients with cancer is a significant predictor of an unfavorable prognosis. The aforementioned survival factors may have the potential to influence patient survival outcomes. Further studies on larger cohorts are warranted.

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.