Brown tumors of the anterior skull base as the initial manifestation of true normocalcemic primary hyperparathyroidism: report of three cases and review of the literature

Abstract

Brown tumor is a bone lesion secondary to hyperparathyroidism of various etiologies. Skeletal involvement in primary hyperparathyroidism secondary to parathyroid adenoma is very uncommon and brown tumor has become extremely a rare clinical entity. Hyperparathyroidism is usually associated with high levels of serum calcium. Brown tumor as the only and initial symptom of normocalcemic primary hyperparathyroidism is extremely rare. Moreover, involvement of the skull base and the orbit is exceedingly rare. The authors would report three cases of brown tumor of the anterior skull base that were associated with true normocalcemic primary hyperparathyroidism. Clinical manifestations, neuroimaging findings, pathological findings, diagnosis and treatment of the patients are discussed and the relevant literature is reviewed. KeywoRds: Brown tumor, Skull base, Normocalcemia, Primary hyperparathyroidism ÖZKahverengi tümör çeşitli etiyolojiler nedenli hiperparatiroidiye sekonder bir kemik lezyonudur. Paratiroid adenomuna sekonder primer hiperparatiroidide iskelet tutulumu çok nadirdir ve kahverengi tümör çok nadir bir klinik olay haline gelmiştir. Hiperparatiroidi genellikle yüksek serum kalsiyum düzeyleriyle ilişkilidir. Normokalsemik primer hiperparatiroidinin tek ve başlangıç belirtisi olarak kahverengi tümör çok nadirdir. Ayrıca kafatası tabanı ve orbitanın tutulması son derece nadirdir. Yazarlar gerçek normokalsemik primer paratiroidi ile ilişkili anterior kafatası tabanının üç kahverengi tümör vakasını sunmaktadır. Klinik bulgular, nörogörüntüleme bulguları, patolojik bulgular ve bu hastaların tanı ve tedavisi sunulmakta ve ilgili literatür gözden geçirilmektedir.

Sinonazal Bölge Benign Kemik Tümörlerinin Radyolojik Değerlendirmesi

“…Management is based on the reduction of parathormone levels; in some cases this is only possible with parathyroidectomy. The bony lesions regress once the parathormone levels are back to normal (4,9,23). Our case was a 43 year old male patient.…”

Educational Case: Langerhans cell histiocytosis

“…Furthermore, a lytic lesion of the skull due to a brown tumor caused by normocalcemic primary hyperparathyroidism is rare, primarily affecting the skull base and, in children, the mandible. 6 Therefore, the differential diagnoses that may be ruled out are neuroblastoma and hyperparathyroidism. Still, other diseases affecting multiple bones should be considered.…”

Determining primary from secondary hyperparathyroidism: A review of current management

“…Brown tumors usually occur in the medullary shaft of long bones, but also include the mandible, maxilla, clavicle, metacarpal bones, ribs, pelvic bones, and rarely the cranium. Multiple brown tumors are exceedingly rare, only six cases reported in English literature [10]. Histologically, these tumors are non-encapsulated and are characterized by abundant vascularity, stroma consisting of fibrous connective tissue, with a proliferation of fibroblasts, deposition of hemosiderin.…”

“…Computed tomography reveals a lytic lesion either hyperdense or heterogeneous with associated soft tissue mass either well-circumscribed or expansile lucent lesion with a rim of calcification and remodeling of the surrounding bone. On magnetic resonance imaging, a hypointense signal is found on T1 weighted imaging, variable signal on T2 weighted images and loss of signal on in-phase images because of the magnetic susceptibility from hemosiderin [10].…”

“…The pathogenesis results most often from a solitary parathyroid adenoma 75-85% of the time. In 15-20% two or more adenomas are found and in one percent parathyroid carcinoma is discovered [2,10,12]. Primary hyperparathyroidism results from a defect in proliferation leading to hypercellularity of one or more glands but also a defect in the negative feedback system [13].…”