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.

Intimal sarcoma of the pulmonary artery with multiple lung metastases: Long-term survival case.

Pulmonary artery intimal sarcoma (PAIS) is a rare tumor with a very poor prognosis. Clinical and radiological findings usually mimic thromboembolic disease, leading to diagnostic delays. The treatment of choice is surgery, and adjuvant chemotherapy and radiotherapy have limited results. We report the case of a 48-year-old male patient, initially suspected with pulmonary thromboembolism. The angio-CT revealed a filling defect in the pulmonary artery trunk. The patient underwent surgery, resulting in with complete resection of the mass with a diagnosis of PAIS. The tumor progressed rapidly in the lung, requiring surgery of multiple lung metastases. The patient was treated with stereotactic body radiation therapy (SBRT) on two occasions for new pulmonary lesions. In the last followup (4 years after initial diagnosis), the patient was disease-free. In conclusion, SBRT proved to be an alternative treatment to metastasectomy, allowing palliative chemotherapy to be delayed or omitted, which may result in improved quality of life.