Parathyroid carcinoma constitutes less than 1 % of primary hyperparathyroidism. The male to female ratio is approximately equal and the mean age at presentation is 40 years. In about half of the patients there is a palpable cervical mass, and serum calcium level is usually above 14 mg/dl. In a case report we present a 21-year-old man with a non-tender, non-mobile bulging mandibular mass. He suffered from fatigue, recent weight loss, hoarseness, polydipsia, polyuria, hematuria, recurrent renal stones and bouts of constipation and diarrhea. A mandibular biopsy confirmed brown tumor. Serum calcium level was 15.4 mg/dl. Cervical ultrasound revealed a hypoecho area suspicious of parathyroid adenoma. Parathyroid carcinoma was later confirmed and en bloc resection was performed. During a two-year follow up there has been no evidence of recurrence or hypercalcemia. This unique case of parathyroid carcinoma in conjunction with brown tumor is the second reported case worldwide.