Endocrine Abstracts

Aim: Brown tumors are a very rare and serious complication of sustained undiagnosed secondary hyperparathyroidism. Diagnosis and differential diagnosis are made by combining clinical, biochemical, radiological and pathological findings. We present the case of a male with chronic renal disease and multiple bone damage.

A 58-year-old male was referred to the endocrine clinic because of lower back and pleural pain. He was an obese smoker with a heavy medical history of hypertension, Stage III chronic kidney disease, obstructive pulmonary disease, heart failure and atrial fibrillation. His past medical history included hyperthyroidism and a large retrosternal goiter. The patient underwent a Thorax CT, which revealed extrapulmonary masses infiltrating the thoracic cage and the ribs. The masses were considered at first to be metastatic and the patient underwent further imaging of the abdomen and cerebrum, as for staging. However, no possible primary lesion was illustrated and the patient was referred for a biopsy. The laboratory tests showed total calcium: 9,2 mg/dl (8,4–10,2), albumin: 4,1 mg/dl (3,5–5), phosphorus: 2,38 mg/dl (2,7–4,5), Parathyroid hormone: 1184 pg/ml (15–65), mild Vitamin D deficiency of 17,3 ng/ml and elevated levels of alkaline phosphate: 595 mg/dl (33–122). Histology confirmed the presence of brown tumors. The patient received supplementation with calcium and vitamin D analogs, as well as cinacalcet, and there was a significant improvement in his laboratory results: calcium 8,3 mg/dl, albumin 3,9 mg/dl, PTH 274 pg/ml, ALP 776 mg/dl and vit D 38 ng/ml. A Thorax CT six months after the diagnosis showed a decrease in the multiple bone lesions and further improvement in his laboratory tests.

Conclusions: Secondary hyperparathyroidism is a common complication of end stage renal disease. Rarely, when undiagnosed and left untreated it can lead to the formation of brown tumors, as a result of osteoclastic activity, fibroblast proliferation and bone resorption. Differential diagnosis should be made from giant cell tumors and metastatic disease.

References: Multilevel brown tumors of the spine in a patient with severe secondary hyperparathyroidism. A case report and review of the literature. Salamone D, Muresan S, Muresan M, Neagoe R.Ann Ital Chir. 2016 Mar 31;87

A brown tumor secondary to hyperparathyroidism in the maxilla, skull, scapula, and femora. Alison Psaila, MDa, Luca Conti, MDb, Alexander P. Azzopardi, BChD, PhDc, and David V. Coppini, MD PROC 2021;34(1):163–165