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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The preparation of dispersed parathyroid cells by collagenase digestion of porcine parathyroid glands, essentially as outlined by Brown et al. (Endocrinology 99: 1582, 1976), is described. The cells secrete parathormone linearly for at least 4 h of incubation and rapidly respond in inverse fashion to changes in the medium calcium and magnesium concentrations over the range 0.5-3.0 mM. In terms of inhibition of secretion, either ion was more effective in the presence of a minimum concentration of the other, indicating that calcium and magnesium affect separate cellular sites. Parathormone was identified both by immunoassay of the whole incubation medium and by its separation by polyacrylamide gels and carboxymethylcellulose chromatography. When the cells were incubated with radioactive amino acids and both the medium and cells were subsequently analyzed on gels, we found that parathyroid secretory protein as well as parathormone and some immunoactive fragments were present. Analysis of the radioactive protein contained in the cells at high and low calcium concentrations revealed that calcium decreased the formation of the secretory protein by approximately 40% without appreciably affecting the formation of proparathormone or parathormone. The secretion of both parathyroid secretory protein and parathormone were inversely proportional to the concentrations of medium calcium or magnesium. The secretion of the latter, however, was more sensitive (95% inhibition) than parathormone (40-60% inhibition) to changes in medium divalent cations. These results suggest that the synthesis, intracellular processing, or secretion of parathormone and parathyroid secretory protein utilize independent calcium- and magnesium-regulated pathways.
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PMID:The effects of calcium and magnesium on the secretion of parathormone and parathyroid secretory protein by isolated porcine parathyroid cells. 74 33

This is a first report of primary hyperparathyroidism (HPT) masquerading as a destructive fibrous sphenoid sinus "Brown tumor" associated with progressive blindness and hypercalcemia. Diagnosis of a Brown tumor was delayed despite serial computerized tomography of the head and repeated transnasal and transethmoid sphenoid biopsies demonstrating diffuse fibrosis. Only detection and medical evaluation of hypercalcemia, demonstrating elevation of both serum calcium and C-terminal parathyroid hormone with an elevated chloride/phosphate ratio, prompted neck exploration, thus confirming a solitary left superior parathyroid adenoma. Postoperative normocalcemia occurred synchronously with the return of light perception and the arrest of sphenoid sinus and parasellar erosion. Although maxillary Brown tumors of secondary HPT have been reported, this is the first report of osteitis fibrosa of the sphenoid sinus. Differential diagnosis of an erosive sphenoid lesion with cranial nerve dysfunction, exclusive of inflammatory or vascular disease, should include sarcoidosis, primary and metastatic sphenoid carcinoma, fibrous dysplasia, giant cell reparative granuloma, midline lethal granuloma, chordoma, and chondrosarcoma. Furthermore, the bony destructive lesions with concomitant hypercalcemia of sarcoidosis and HPT are distinguishable by radiographic and laboratory analyses and by the Dent corticosteroid suppression test. Hypercalcemia of primary HPT is associated with elevated serum C-terminal parathormone, osteitis fibrosa, a negative Dent test, and a chloride/phosphate ratio greater than 33 in 94% of primary HPT patients. Hypercalcemia of sarcoidosis is associated with a normal or decreased C-terminal parathormone assay and a positive Dent test, as well as elevated serum immunoglobulins and erythrocyte sedimentation rate, and a positive angiotensin-converting enzyme assay.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sphenoid sinus brown tumor, hypercalcemia, and blindness: an unusual presentation of primary hyperparathyroidism. 379 83

Primary hyperparathyroidism is a disease characterized by excessive secretion of parathormone. During the course of this disease, bone loss occurs, particularly depending on resorption of the skeletal system. One of the complications of primary hyperparathyroidism is fibrotic, cystic bony changes which is called Brown tumor. Skeletal manifestations in the form of Brown tumors are rare and according to literature occur in less than 2% of patients suffering from any form of hyperparathyroidism. Such rare and multiple benign lesions may simulate a malignant neoplasm and pose a real challenge for the clinician in its differential diagnosis. We present a case of a 23-year-old Indian woman who was evaluated for multiple lytic expansile lesions with a strong suspicion of malignancy and fibrous dysplasia but turned out to be a case of primary hyperparathyroidism.
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PMID:Primary hyperparathyroidism having multiple Brown tumors mimicking malignancy. 2322 63

Brown tumors are bony lesions caused by rapid osteoclastic activity, which rare involved jaws. Renal osteodystrophy (ROD) is associated with different pathogenetic mechanisms--disorder of calcium-phosphate metabolism, impaired metabolism of vitamin D, increased parathyroid activity that lead to extreme concentrations of parathormone. The authors report two cases of jaw enlargement in patients received haemodialysis with excessive increase values of alkaline phosphatase and parathormone in serum. The patients were treated surgically with corrective procedures in maxillo-facial area. ROD of the jaws could be severe complication in dialysis patients with end stage of CKD if no appropriate care aimed at correction or prevention of parathyroid hyperfunction was applied to them.
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PMID:Brown tumor at the jaw in patients with secondary hyperparathyroidism due to chronic renal failure. 2406 63

Brown tumors are rare skeletal manifestations of hyperparathyroidism (HPT) that may mimic cancer metastases. Histopathologically, they are difficult to differentiate from other giant cell lesions. A case is presented of 41-year-old woman with giant cell tumor in parieto-occipital region with injury of external bone lamina, growing into the skull cavity. The mass was suspected of being neoplastic. Numerous osteolytic lesions in the skull skeleton and multifocal bone injuries were observed, also. Elevation in calcium (5.91 mEq/L) and parathormone (1188 ng/mL) concentrations and hypercalciuria (52 mEq/24 h) suggested the diagnosis of HPT initially manifesting as a brown tumor of the skull. Further exploration confirmed the existence of parathyroid adenoma as a cause of the disease. The key treatment for the condition was surgical excision of the adenoma followed by the normalization of parathyroid function and significant reduction in size of skull tumor and other lesions.
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PMID:Parathyroid adenoma diagnosed on the basis of a giant cell tumor of parieto-occipital region and multifocal bone injuries. 2446 10

Brown tumors result from excess osteoclast activity and consist of collections of osteoclasts intermixed with fibrous tissue and poorly mineralized woven bone. They are secondary to hyperparathyroidism (HPT). Their incidence is higher in primary than in secondary hyperparathyroidism. We report a 69 years-old male, admitted in a state of confusion, lethargy and bedridden, with a pathological fracture of the femur caused by a brown tumor. The laboratory examination revealed a hypercalcemia (8.85 mEq/L), with high levels of ionized Ca (5.48 mEq/L), serum alkaline phosphatases (416 U/L) and serum parathormone (120 pg/mL). Ultrasound examination of the neck showed a large parathyroid tumor, probably corresponding to a carcinoma. A primary HPT was diagnosed. The patient was hydrated and high doses of diuretics and bisphosphonates were administered. After correction of serum calcium and neurologic symptoms, the patient was operated, performing an extensive resection of the tumor. The pathology report confirmed the diagnosis of parathyroid carcinoma.
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PMID:Brown tumors of the femur and pelvis secondary to a parathyroid carcinoma: report of one case. 2537 13

Brown's tumor, also referred as osteitis fibrosa cystica is a rare nonneoplastic diagnostically challenging consequence of hyperparathyroidism (HPT) which occurs due to increased parathormone secretions in blood, causing excessive calcium resorption from kidneys, bone resorption, and phosphaturia. Brown's tumor is a misnomer, presenting as cystic expansile lesions in bone, often misdiagnosed as neoplastic lesion or granuloma or abscess in bones. It can affect long bones, clavicle, ribs, and pelvis. According to literature, skeletal manifestations of Brown tumor is relatively rare and occurs in <2% of the cases of HPT. We present a case of a female 15-year-old patient who presented with bleeding gums and an expansile lesion in mandible whose previous investigations elsewhere suggested a malignant lesion. However, further investigations revealed it to be Brown's tumor with primary HPT which is a rare genetic disorder, known as HPT-Jaw Tumor Syndrome (HPT-JT).
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PMID:Osteitis fibrosa cystica of mandible in hyperparathyroidism-jaw tumor syndrome: A rare presentation and review of literature. 2938 22