A 24-year-old female patient with parathyroid carcinoma,the rarest endocrine malignancy,had two pregnancies.In the first pregnancy,she had severe nausea and fatigue.Hypercalcemia and hyperparathyroidism were diagnosed in the postpartum period.Hyperemesis gravidarum masked a diagnosis of hypercalcemia.Neck ultrasound and Tc-99 m sestamibi found an enlarged lower right parathyroid gland.The gland was surgically removed,and an initial pathology report described atypical adenoma.Shortly afterward,she became pregnant again.During the second pregnancy,her calcium level was frequently controlled but was always in the normal range.Normocalcemia is explained by the specific physiology of pregnancy accompanied by hemodilution,hypoalbuminemia and maternal hypercalciuria(mediated by increased glomerular filtration).During lactation,calcium levels rose,and a newneck ultrasound showed a solitary mass in the area of prior surgery and an enlarged pretracheal lymph node.Fine needle aspiration of the solitary mass and node showed parathyroid carcinoma cells.The tumor mass was resected en bloc with the contiguous tissues and surrounding lymph nodes(pathology report; parathyroid carcinoma with metastases).Over the next five years,four consecutive surgeries were performed to remove malignant parathyroid tissue,lymph nodes and local metastases.Following the surgical procedures,no hypocalcemia was observed.More serious hypercalcemia recurred; the calcium level was difficult to control with a combination of pamidronate,cinacalcet and loop diuretic.No elements of multiple endocrine neoplasia were present. A 24-year-old female patient with parathyroid carcinoma, the rarest endocrine malignancy, had two pregnancies. The first pregnancy, she had severe nausea and fatigue. Hypercalcemia and hyperparathyroidism were diagnosed in the postpartum period. Hyperemesis gravidarum masked a diagnosis of hypercalcemia .Neck ultrasound and Tc-99 m sestamibi found an enlarged lower right parathyroid gland. Gland.The gland was surgically removed, and an initial pathology report described atypical adenoma.Shortly afterward, she became pregnant again. During the second pregnancy, her calcium level was frequently controlled but was always explained in the normal range. Normocalcemia is explained by the specific physiology of pregnancy accompanied by hemodilution, hypoalbuminemia and maternal hypercalciuria (mediated by increased glomerular filtration). Fluid lactation, calcium levels rose, and a newneck ultrasound showed a solitary mass in the area of ​​prior surgery and an enlarged pretracheal lymph node. Fine needle aspiration of the so litary mass and node showed parathyroid carcinoma cells. The tumor mass was resected en bloc with the contiguous tissues and surrounding lymph nodes (pathology report; parathyroid carcinoma with metastases). Over the next five years, four consecutive surgeries were performed to remove malignant parathyroid tissue , lymph nodes and local metastases. Folding the surgical procedures, no hypocalcemia was observed. More serious hypercalcemia recurred; the calcium level was difficult to control with a combination of pamidronate, cinacalcet and loop diuretic. No elements of multiple endocrine neoplasia were present.