Endocrine Abstracts

Introduction

The differential diagnosis between benign and malignant parathyroid neoplasms may be challenging and should always be based on clinical and histological criteria. We are presenting a case series of three patients with clinical, biochemical and imaging findings supporting the presence of a malignant neoplasm but histological findings confirming the diagnosis of a parathyroid adenoma.

Case 1

A 24-year-old man presented with acute pyelonephritis in the presence of obstructive urinary tract calculi of the right kidney. Laboratory examination was indicative of primary hyperparathyroidism (PHPT) (Total Ca = 17mg/dl, PTH = 1000 pg/ml). Parathyroid ultrasound imaging demonstrated a 3 cm tumor under the left lobe of the thyroid gland. Plain radiographs revealed the presence of multiple osteolytic lesions in the humeri, femurs and pelvic bones, as well as subperiosteal bone resorption of the finger phalanges of the hand.

Case 2

A 32-year-old woman was admitted in the ICU due to acute pyelonephritis and sepsis in the presence of obstructive urolithiasis of the right kidney. Laboratory examination was indicative of PHPT (Total Ca = 13.5mg/dl, PTH = 1500 pg/ml). Parathyroid ultrasound imaging demonstrated a 6.5 cm tumor under the right lobe of the thyroid gland. Plain radiographs revealed the presence of pepper pot appearance of the skull, subperiosteal resorption in the middle phalanges of the second finger of the hands as well as the appearance of floating tooth syndrome.

Case 3

A 52-year-old woman presented with bilateral urolithiasis and laboratory results indicative of PHPT (Total Ca = 13mg/dl, PTH = 504 pg/ml). She had a history of parathyroidectomy of 2.5 hyperplastic parathyroid adenomas and was receiving treatment with cinacalcet due to persistent hypocalcaemia. CT imaging revealed the presence of a 5 cm tumor in the mediastinum originating from the right inferior parathyroid gland. Plain radiographs revealed the presence of brown tumors in the right femur and ilium. All three patients underwent surgical removal of the parathyroid tumors and histopathological examination confirmed the presence of parathyroid adenomas. In all cases, postsurgical PTH concentrations returned to normal range, while the patients developed hungry bone syndrome and were offered calcium and alfacalcidol supplementation.

Conclusion

Large parathyroid adenomas may present with severe clinical manifestations such as osteitis fibrosa cystica, severe urolithiasis, as well as extremely high PTH and calcium concentrations, even in young-aged patients. Since the biological behavior of such adenomas is not definite, long-term surveillance is essential.