Abstract
BACKGROUND: Parathyroid carcinoma is a rare malignancy with an increasing incidence. Most patients are characterized by the presence of severe primary hyperparathyroidism, especially hypercalcemia, while patients with normal level of serum calcium are extremely rare. Unfortunately, patients free of hypercalcemia are usually diagnosed at a later stage and suffer from a rather poor prognosis. CASE PRESENTATION: We describe a patient diagnosed with intrathyroidal normocalcemic parathyroid carcinoma, whose preoperative ultrasonography suggests that the tumor is located inside the thyroid gland and present without obvious clinical manifestations, which makes it more challenging for diagnosis. CONCLUSIONS: Preoperative suspicion of malignancy is of great importance for advanced management while preoperative diagnosis is rather challenging with the limited contribution of imaging examinations. Any abnormality in serum level of calcium or parathormone may help to make an initial diagnosis especially when the level is extremely high. We introduce this case of initial misdiagnosis of an intrathyroidal parathyroid carcinoma, mimicking a suspicious thyroid nodule, to focus on the possible anomalous presentations of this rare condition and on its optimal management.