Introduction: Incidence of ectopic parathyroid glands in individuals is ~6%, the most common location being the thymic capsule or the superior mediastinum.
Case: We present the case of 21-years-old female with a recent history of osteoclastoma affecting the maxillary bone and the mandible, together with increased values of the parathyroid hormone (over 20 times the normal value), total calcium and alkaline phosphatase and decreased serum phosphorus. A cervico-mediastinal MRI was performed with the disclosure of a well delimited 5/5.5/2 cm tumoral mass in the antero-superior part of the mediastinum, as well as multiple cystic bone tumors affecting the maxillary bone, mandible, clavicle, humeral head and scapula - osteitis fibrosa cystica in context of the primary hyperparathyroidism. In September 2010 thymectomy was performed.
Material and methods: Tissue fragments from the thymectomy specimen were routinely processed and stained with H&E. Supplimentary Ki-67 antigen (MIB 1 clone), En Vision method, DAB visualization was made.
Results: Within the capsule of the thymus was found a nodule, embedded in connective tissue, formed mainly by parathyroid epithelial cells, chief cell type, patterned in nests and small follicles; focal pleomorphic nuclei were observed, but no evidence of malignancy such as vascular or soft tissue invasion. Immunohistochemistry for the cell cycle marker Ki67 has been 2%, so the final diagnosis was that of ectopic parathyroid adenoma, with mild atypia.
Conclusion: After surgical removal of the mediastinal mass, imagistically suspected and histopathologically confirmed as ectopic parathyroid tissue, the syndrome of primary hyperthyroidism was resolved.
30 Apr - 04 May 2011
European Society of Endocrinology