Case Report: Life-threatening hypercalcemia associated with MMR-deficient endometrial carcinoma secreting parathyroid hormone

Ectopic secretion of parathyroid hormone (PTH) is a rare cause of hypercalcemia in malignancy patients. A 56-year-old woman with life-threatening hypercalcemia was caused by poorly-differentiated endometrial carcinoma secreting PTH with concomitant nodular goiter mimic parathyroid tumors. The elevated level of PTH and calcium decreased immediately after cytoreductive surgery (CRS). The pathology confirmed mismatch repair (MMR)-deficient endometrial carcinoma with PTH expression. The patient received four-course chemotherapy and one-course immunotherapy after CRS. The disease progression led to multiple organ failure and death about five months after CRS. To our knowledge, this is the first case of hypercalcemia caused by MMR-deficient endometrial carcinoma with ectopic PTH secreting and the first report of malignancy associated hypercalcemia complicated with nodular goiter.

Automated summary

Ectopic secretion of parathyroid hormone (PTH) by poorly-differentiated endometrial carcinoma led to life-threatening hypercalcemia in a 56-year-old woman, accompanied by nodular goiter mimic parathyroid tumors. Cytoreductive surgery (CRS) immediately reduced the levels of PTH and calcium. Pathological examination confirmed MMR-deficient endometrial carcinoma expressing PTH. The patient underwent four-course chemotherapy and one-course immunotherapy after CRS, but disease progression resulted in multiple organ failure and death. This is the first reported case of hypercalcemia caused by MMR-deficient endometrial carcinoma with ectopic PTH secretion, as well as the first report of malignancy-associated hypercalcemia complicated with nodular goiter.