Gastrointestinal Stromal Tumor Induced Hypercalcemia

Hypercalcaemia in gastrointestinal stromal tumour and sarcoidosis: a case report

BACKGROUND

Hypercalcaemia is a common manifestation of sarcoidosis but is sparingly described in gastrointestinal stromal tumours (GISTs). We describe a case of acute kidney injury and hypercalcemia resulting from simultaneous diagnosis of GIST and sarcoidosis, the presentation of which has not yet been reported.

CASE PRESENTATION

A 61-year-old male presented with acute kidney injury and hypercalcemia, with elevated 1,25-dihydroxyvitamin D levels. Investigations demonstrated a large gastric antral mass which was resected and proven to be GIST. Histopathology of incidentally found liver nodules revealed non-necrotising epithelioid granulomas consistent with concomitant sarcoidosis. The hypercalcemia was successfully treated with bisphosphonate therapy, resection of the GIST and a four month course of corticosteroids, which was truncated due to a mycobacterial infection.

CONCLUSIONS

Our case report is the first to describe hypercalcemia due to GIST and biopsy-proven sarcoidosis, thereby raising the possibility of a common pathophysiological pathway relating the two entities. We review the literature describing the mechanisms of hypercalcaemia in GIST and the association between GIST and sarcoidosis.

Gastrointestinal stromal tumour-induced hypercalcaemia

Hypercalcaemia is recognised as the most common oncological metabolic emergency, with several proposed underlying mechanisms. Nevertheless, hypercalcaemia has been rarely reported as a complication in patients with gastrointestinal stromal tumours (GISTs). GISTs are uncommon mesenchymal tumours of the gastrointestinal tract. There are only nine previous cases of hypercalcaemia occurring in patients with GIST reported in the literature. We report a case of a man in his 70s with a background of metastatic GIST on fourth-line treatment. The patient presented with new hypercalcaemia and acute kidney injury. Despite medical management, his calcium remained elevated and he deteriorated secondary to significant disease progression.

Calcitriol-Mediated Hypercalcemia, Somatostatin Receptors Expression and 25-Hydroxyvitamin D3-1α- Hydroxylase in GIST Tumors

Hypercalcemia is a common complication in cancer patients Mainly caused by Parathyroid hormone-related protein (PTHrP) secretion and metastasis. Calcitriol secretion is a rare source of hypercalcemia in solid tumors, especially in gastrointestinal stromal tumors (GIST). We present a case report of a female patient with a 23 cm gastric GIST that expressed somatostatin-receptors and presented with severe hypercalcemia due to calcitriol secretion. Calcium control was achieved with medical treatment before the use of targeted-directed therapies. Surgery was performed and allowed complete tumor resection. Two years later, patient remains free of disease. Molecular analysis revealed the mRNA expression of 25-hydroxyvitamin D₃-1-hydroxylase (1αOHase) and vitamin-D receptors in the tumor cells, confirming the calcitriol-mediated mechanism. Furthermore, the expression of the endotoxin recognition factors CD14 and TLR4 suggests an inflammatory mediated mechanism. Finally, the expression of somatostatin-receptors, especially SST2 might have been related with clinical evolution and prognosis in this patient.

Refractory hypercalcaemia secondary to localised gastrointestinal stromal tumour

Gastrointestinal stromal tumours are a rare form of intra-abdominal neoplasm derived from mesenchymal tissue, typically presenting with abdominal pain, anaemia or bleeding into the bowel or abdominal cavity. Hypercalcaemia is an unusual complication, having been documented in only seven previous patients, all of whom had advanced metastatic disease. We present a case of treatment-resistant hypercalcaemia in a patient with non-metastatic gastrointestinal stromal tumour, which resolved following excision of the tumour.