Granulomatous infiltration of a parathyroid adenoma presenting as primary hyperparathyroidism in a woman: a case report

INTRODUCTION Hypercalcemia can be associated with vitamin D (1,25(OH)2D3) -mediated granulomatous disorders in addition to primary hyperparathyroidism (PHPT). Although most patients with granulomatous disease-related hypercalcemia are asymptomatic, symptoms and signs of chronic hypercalcemia can occur. There are many reports about co-presentation of a parathyroid adenoma and a granulomatous disorder in the literature. However, granulomatous inflammation within a parathyroid adenoma is very rare. CASE PRESENTATION A 50-year-old Caucasian woman presented with generalized bone pain and muscular weakness. Biochemical findings suggested PHPT. She underwent excision of an enlarged right inferior parathyroid gland. Histopathological analysis revealed features of a parathyroid adenoma with foci of epithelioid non-caseating granulomas. The etiology of the granulomatous infiltration could not be determined. She is still normocalcemic at the ninth month after surgery and is being followed for the possible manifestation of an occult disease. CONCLUSION Granulomatous infiltration of a parathyroid adenoma is a rare condition. Pathological examination of the excised adenoma is the only way to diagnose the underlying occult granulomatous disorder. Clinicians should also consider persistent hypercalcemia to be a possible indicator of concomitant parathyroid adenoma.