Malignancy of parathyroid: An uncommon clinical entity
Our patient was an 80-year-old female with a history of generalized weakness, pain in the back and knees for 4 years, and bilateral flank pain for 1 year. She was seeing a dentist for a tooth extraction when she was advised to undergo an x-ray for a suspicious swelling on the lingual aspect of right mandible which revealed an osteolytic lesion of the vertical ramus of right mandible []. Same day an ultrasound abdomen done for her flank pain showed bilateral tiny renal stones. Patient had no urinary complaints. Other routine investigations at that time were essentially normal other than raised S. Creatinine.\nFor further confirmation of the lytic lesion of the right mandible a computerized tomography CT head and neck was done which demonstrated an expansile osteolytic lesion in the right posterior body, right mandibular ramus, and coronoid process (reported as brown tumor of mandible) and a well-defined lesion posterio-inferior to the right lobe of thyroid showing few specks of calcification (parathyroid lesion). At this point in view of her lytic mandibular lesion, bilateral renal calculi and a suspected parathyroid lesion the probability of hyperparathyroidism was entertained and patient was evaluated further. Her laboratory values were: S. Ca+ 14.30 mg%, S. Creatinine 1.78 mg%, S. BUN 47 mg%, S. Alk Phos 557 IU/L, and Intact PTH 1881 pg/ml. A “salt and pepper” appearance seen on x-ray of the skull [] and lytic lesions in the left frontal region and left supracetabular region on respective x-rays further strengthened the diagnosis. Preoperative vitamin D levels were not obtained nor was a bone mineral density done. There was no history of pancreatitis, fractures, depression/psychiatric features, and constipation. Physical examination was essentially normal and there was no palpable neck mass. Based on these findings, a diagnosis of primary hyperparathyroidism due to parathyroid adenoma was made; however, she did not undergo a sestamibi scan.\nPatient was taken up for right inferior parathyroidectomy under GA. A mini incision of 2.5 cm was made over the right side of neck, two fingerbreadth above the sternal notch. The adenoma was found posterior to the inferior border of the right lobe of thyroid with minimal adhesions to the thyroid. The size of the adenoma was 1.5 × 1 × 0.4 cm and it weighed 2 g. No lymph nodal excision was done. Excised gland was sent for histopathological examination.\nPostoperatively on day 1, her serum PTH fell down to 12.45 pg/ml and serum calcium levels came down to 9.4 mg/dl.\nTo our surprise, the histopathologist reported it as a carcinoma of the parathyroid gland. The tumor was composed predominantly of chief cells arranged in multiple nodules separated by thick fibrous bands. There was capsular invasion by tumor cells along with lymphovascular invasion []. Tumor cells were uniform with minimal atypia and brisk mitotic activity (0–4/10 HPF).\nLater an ipsilateral hemithyroidectomy was done on the basis of histopathology report as a completion procedure.\nThere was no preoperative or postoperative evidence suggestive of a distant spread of the malignancy.\nAt present, she is maintaining normocalcemia with oral calcium and calcitriol supplementation. She is on regular follow-up and is not receiving any chemo or radiotherapy.