Osteitis Fibrosis Cystica: Classical Case Report of an Uncommon Presentation in a Young Female

Osteitis fibrosa cystica (OFC) is a skeletal disease related to long standing, end-stage hyperparathyroidism. However, nowadays hypercalcemia due to primary or secondary hyperparathyroidism can often be detected early by laboratory screening and imaging modalities; consequentially the frequency of osteitis fibrosa cystica has drastically declined. OFC, also termed as Brown tumor, can mimic primary bone tumors clinically, which often leads to misdiagnosis and inappropriate management. Moreover due to its rarity, it is usually not considered initially in the differential diagnosis of bony tumors. Case presentation: This is the case of a 19-year-old female, who presented with pain over the left ankle region for 3 months. The biochemical screening revealed a picture consistent with primary hyperparathyroidism and the radiologically proven to be left inferior parathyroid adenoma. She underwent excision of the primary parathyroid adenoma, and gradual regression of symptoms was noted postoperatively. Osteitis fibrosa cystica is a rare manifestation of hyperparathtyroidism, which has become a forgotten entity lately due to early identification of hypercalcaemia by modern techniques. A delay in the diagnosis of parathyroid adenoma results in manifestations that can be avoided. The diagnosis of OFC requires a high degree of clinical suspicion. When hypersecretion of PTH is corrected, spontaneous regression of the lesion is expected.