RESUMEN
HISTORY: A 29-year-old man presented with a giant cell granuloma of the maxilla that had initially been diagnosed as a "brown tumor" (a bone replacing mass of fibrous tissue containing hemosiderin-pigmented macrophages and multinucleated giant cells). Because serum calcium and PTH were elevated, primary hyperparathyroidism was diagnosed. Three months later a parathyroid carcinoma and a brown tumour in the left femur were identified and removed surgically. Hyperparathyroidism-jaw tumor syndrome was suspected. INVESTIGATIONS AND DIAGNOSIS: Mutation analysis of the DNA revealed heterozygous nonsense mutation R234X in exon 7 of the HRPT2 gene, a tumor suppressor gene responsible for the HPT-JT syndrome. Subsequent studies indicated that the patient had inherited the HRPT2 mutation from his father who was now 68 years old. He showed no symptoms of the hyperparathyroidism-jaw tumor syndrome; serum calcium and PTH were normal. The R234X mutation was also found in the patient}s sister. She had been diagnosed for primary hyperparathyroidism at the age of 32 years. Serum calcium and PTH levels were within the normal range after subtotal parathyroidectomy. FURTHER COURSE: Follow up over 3 years showed no clinical, morphological or biochemical relapse of primary hyperparathyroidism. CONCLUSION: The identification of the R234X mutation is not only important for the patient himself, but also for other family members who could benefit from being identified as mutation carriers. This information can be used for the early detection and removal of malignant parathyroid tumours.