Osteitis Fibrosa Cystica

Excerpt

Osteitis fibrosa cystica (OFC), a disorder of skeletal bone, is a pathognomonic yet infrequent finding of late-stage hyperparathyroidism. OFC is also referred to by the eponym 'von Recklinghausen Disease of the Bone,' highlighting the description by Friedrich Daniel von Recklinghausen in 1891; however, it is noteworthy that the first description of this phenomenon was posed 27 years earlier in 1864 by Gerhard Engel. Moreover, it was not until 1904 that von Askanasy demonstrated the correlation between OFC and the parathyroid glands.

OFC translates to 'cystic bone destruction' and occurs in the setting of chronic and sustained overactivity of the parathyroid glands with excessive release of parathyroid hormone (PTH) acting upon osseous tissues. While once a common manifestation of hyperparathyroidism, OFC is now a rare occurrence in Western countries, especially in the United States, largely due to the introduction of auto analyzers in the 1970s-1980s, allowing earlier detection of even asymptomatic hyperparathyroidism and resultant prevention of late-stage osseous manifestations.

OFC may occur in any setting of sustained elevation of PTH, including primary, secondary, and tertiary hyperparathyroidism. Excessive osteoclast activation manifests as but is not limited to, bone swelling, pain, deformity, depleted bone mineral density, and fractures. Lesions may be either single or multiple and are characterized histologically as "brown tumors" due to repetitive microtrauma and microfractures, leading to hemosiderin deposition; however, this is a misnomer, as they do not harbor neoplastic potential. While OFC may be progressive alongside continued activation of the parathyroid glands and stimulation of the osteoclasts, treatment of the underlying disorder of hyperparathyroidism, most often with a parathyroidectomy, is curative with ultimate resolution of the disease.