Metabolic bone disease in the context of metastatic neuroendocrine tumor: differentiation from skeletal metastasis, the molecular PET-CT imaging features, and exploring the possible etiopathologies including parathyroid adenoma (MEN1) and paraneoplastic humoral hypercalcemia of malignancy due to PTHrp hypersecretion

Ranade, Rohit; Basu, Sandip

doi:10.4103/1450-1147.172307

Cited by 5 publications

(1 citation statement)

References 12 publications

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“…Furthermore, up to 30–40% of the GEP-NETs are known to be functional (i.e. causing symptoms mediated by excessive hormone/peptide secretion) [ 16 ], and evidence is accumulating that PRRT is valuable in controlling these functional neuroendocrine tumor syndromes [ 17 – 22 ]. This case documents a rare finding of refractory hypercalcaemia of underlying malignancy due to a calcitriol-producing pancreatic neuroendocrine tumor, responding to peptide receptor radionuclide therapy (PRRT).…”

Section: Introductionmentioning

confidence: 99%

Peptide receptor radionuclide therapy controls inappropriate calcitriol secretion in a pancreatic neuro-endocrine tumor: a case report

et al. 2020

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Background Hypercalcemia of malignancy is not uncommon in patients with advanced stage cancer. In rare cases the cause of the hypercalcemia is excessive production of calcitriol, the active form of vitamin D. Although inappropriate tumoral secretion of calcitriol is typically associated with lymphomas and some ovarian germ cell tumors, we present a case of calcitriol overproduction-induced hypercalcemia due to a pancreatic neuroendocrine tumor. The high expression of somatostatin receptors on this neuroendocrine neoplasm opened up the opportunity to treat the patient with radiolabelled somatostatin analogs, which successfully controlled the refractory hypercalcaemia and calcitriol levels. This case documents a rare finding of refractory hypercalcaemia of underlying malignancy due to a calcitriol-producing pancreatic neuroendocrine tumor, responding to peptide receptor radionuclide therapy (PRRT). Case presentation A 57 years-old patient presented with back pain, general discomfort, polydipsia, polyuria, fatigue and recent weight loss of 10 kg. Clinical examination was normal and there was no relevant medical history. Biochemical evaluation showed hypercalcemia with markedly increased calcitriol levels. CT-thorax-abdomen and ultrasound guided biopsy revealed a pancreatic neuroendocrine tumor with multifocal liver metastases, suggesting that excessive overproduction of calcitriol by this neuroendocrine tumor was the cause of the refractory hypercalcemia. The patient was eligible for PRRT. Four cycles of 177Lu-DOTATATE PRRT resulted in a morphological response and a normalization of serum calcium levels, confirming the hypothesis of a calcitriol producing pancreatic neuroendocrine tumor. Progression of liver metastases warranted further therapy and temozolomide-capecitabine was started with morphological and biochemical (serum calcium, calcitriol) stabilization. Conclusion Although up to 30–40% of gastroenteropancreatic neuroendocrine tumors are known to be functional (i.e. producing symptoms associated with the predominant hormone/peptide secreted), calcitriol secreting pancreatic neuroendocrine tumors are very rare. However, treatment with PRRT resulted in normalization of calcium and calcitriol levels, strongly supporting the hypothesis of a calcitriol-producing pancreatic neuroendocrine tumor.

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Section: Introductionmentioning

confidence: 99%