Osteitis fibrosa cystica-a forgotten radiological feature of primary hyperparathyroidism

Although bone disease and stone disease are the universally accepted classical manifestations of primary hyperparathyroidism, clinical parathyroid bone disease is rarely seen today in the United States (<5% of patients) and Western Europe. Nevertheless, in a given patient, classical skeletal involvement can be the first sign of primary hyperparathyroidism, but not recognized because it is not usually included, anymore, in the differential diagnosis of this manifestation of skeletal disease. We describe four cases of primary hyperparathyroidism in which the first clinical manifestation of the disease was a pathological fracture that masqueraded as a malignancy. The presence of large osteolytic lesions gave rise to the initial diagnosis of a primary or metastatic cancer. In none of the reported cases was primary hyperparathyroidism with osteitis fibrosa considered as the diagnosis. It would seem to us that this course is best explained by the fact that in many countries such manifestations of primary hyperparathyroidism have become a rarity. In fact, the incidence of osteitis fibrosa among patients with primary hyperparathyroidism in the US is estimated as so rare, that in majority of medical centers routine x-ray examinations of the bones in these patients is not recommended. The X-ray or computed tomography scan findings of osteitis fibrosa cystica include lytic or multilobular cystic changes. Multiple bony lesions representing brown tumors may be misdiagnosed on computed tomography scan as metastatic carcinoma, bone cysts, osteosarcoma, and especially giant-cell tumor. Distinguishing between primary hyperparathyroidism and malignancy is made readily by the concomitant measurement of parathyroid hormone which in primary hyperparathyroidism, again, will be markedly elevated. In the hypercalcemias of malignancy, such elevations of parathyroid hormone are virtually never seen.

CONCLUSION

When radiographic evidence of a lytic lesion and hypercalcemia are present, primary hyperparathyroidism should always be considered in the differential diagnosis.

Multilevel brown tumors of the spine in a patient with severe secondary hyperparathyroidism A case report and review of the literature

BACKGROUND

The brown tumour is an extreme form of osteitis fibrosa cystica, representing a serious complication of the advanced primary or secondary hyperparathyroidism. It occurs in settings of high levels parathyroid hormone, like in primary or secondary hyperparathyroidism, with a frequency of 3-4% and 1.5-13% respectively, usually affecting young people.

CASE REPORT

The authors report a case of a 45 years old woman on long-term hemodialysis, with severe secondary hyperparathyroidism. The main clinical complaints were neck pain, lower thoraco-lumbar back pain, persistent left groin pain, and bilateral lower extremities weakness. The computed tomography scan revealed multiple spine brown tumors affecting the cervical, thoracic and lumbar level. After an initial partial response to the treatment of two years with Cinacalcet, a deterioration of the secondary hyperparathyroidism occurred (hypercalcemia, hyperphosphatemia) and the patient was referred for parathyroidectomy. The patient underwent total parathyroidectomy with auto-transplantation, with a positive postoperative result.

CONCLUSIONS

Secondary hyperparathyroidism can lead, during its course, to osteolytic bone lesions called brown tumors. If the medical treatment fails, the surgical removal of the parathyroid glands with autotransplant remains the only treatment of the bone lesions progression. Reviewing the relevant literature in English (until March 2015), we found 24 cases of symptomatic vertebral brown tumors. To the authors' knowledge, this is the first case which describes a multilevel spine involvement (more than two), and the fifth describing a cervical localization.

KEY WORDS

Hypocalcaemia, Secondary hyperparathyroidism, Spine brown tumors.

From mild to severe primary hyperparathyroidism: the Brazilian experience

Primary hyperparathyroidism often presents as an asymptomatic disorder. In our institution, routine serum calcium measurements have now been used as part of medical examination for 23 years. Out of 124 patients consecutively seen at our institution, 47% presented with no symptoms related to the disease, while 25% presented with severe skeletal involvement and osteitis fibrosa cystica, 25% with renal stone disease without overt bone involvement, and 2% with the typical neuropsychiatric syndrome. This same pattern is seen in the city of São Paulo. In severe disease pathological fractures are frequently seen, especially in long bones of the lower extremities, and also loss of lamina dura of the teeth and salt-and-pepper appearance of the skull. Bone mineral density is extremely low in these patients but usually show remarkable recovery following surgical cure. Serum PTH and bone markers are considerable higher in severely affected patients, who also have a high rate of vitamin D deficiency, and the parathyroid lesion is easier located compared with asymptomatic patients. From pathological specimens 87% had histological confirmation of a single adenoma, 6.4% multiple gland hyperplasia and 3.8% carcinoma.

Inhibition of 1,25(OH)2D production by hypercalcemia in osteitis fibrosa cystica: influence on parathyroid hormone secretion and hungry bone disease

Primary hyperparathyroidism is usually associated with normal or elevated serum 1,25-dihydroxyvitamin D [1,25(OH)2D] levels. We report a 63-year-old patient with extreme hypercalcemia (ionized serum calcium, 2.51 mmol/l; normal range, 1.19-1.36), very high serum concentrations of intact immunoreactive parathyroid hormone (iPTH) (145 pmol/l; normal range, 1-6.8), radiological lesions of osteitis fibrosa cystica, only mildly impaired renal function (creatinine clearance, 69 ml/min/m2) and very low serum levels of 1,25(OH)2D (28.8 pmol/l; normal range, 72-120). Presurgery normalization of the calcemia with normal saline, salmon calcitonin and pamidronate caused an increase in 1,25(OH)2D serum concentration to 228.3 pmol/l. A negative correlation could be established between ionized calcium and 1,25(OH)2D levels during that period (r2 = 0.80, P < 0.04). While serum calcium decreased with treatment, serum iPTH also decreased to 48.6 pmol/l, suggesting some 1,25(OH)2D inhibition of parathyroid adenoma function. Serum alkaline phosphatase also rose from 309 to 390 units/l (normal range, 25-97), suggesting the beginning of resolution of her osteitis fibrosa cystica prior to surgery. Surgical removal of a parathyroid adenoma was associated with a decrease in serum calcium and iPTH levels. To our surprise, the hypocalcemia could be managed easily with 1500 mg of oral calcium carbonate daily, even if the hungry bone disease became more active with an increase in alkaline phosphatase to 486 units/l. This was explained by the very high levels of serum 1,25(OH)2D (> 200 pmol/l) which prevailed in the postsurgery period and were probably related to decreased bone resorption and increased bone formation. This case illustrates that normalizing serum calcium prior to surgery in patients with primary hyperparathyroidism and osteitis fibrosa cystica can be highly beneficial.

[Hormonal markers of early-stage osteitis fibrosa in patients on hemodialysis]

The diagnosis of renal osteodystrophy is straightforward when the disease has reached an advanced stage and the pathology is extremely difficult to treat, whereas it is considerably more complex during the early stages. A study was carried out to assess the sensitivity of some biochemical, hormonal and instrumental markers in the early diagnosis of osteitis fibrosa in patients undergoing hemodialysis due to chronic renal insufficiency. Of these markers, the assay of whole molecule PTH appeared to be the most sensitive and specific biological marker.

[Osteitis fibrosa cystica von Recklinghausen]

We present the case of a woman with classical osteitis fibrosa cystica generalisata von Recklinghausen, caused by a single adenoma of the left inferior parathyroid gland. After six months with increasing bone pain, pathological fractures and cystic lesions radiologically, hyperparathyroidism was diagnosed by persistent elevated levels of serum calcium, and elevated levels of PTH. Surgical extirpation of the parathyroid adenoma caused a period with severe hypocalcemia followed by complete clinical restitution. The diagnosis should be considered in any case of persistent bone pain and uncharacteristic fatigue.

Spontaneous hypercalcemia in patients undergoing dialysis. Etiologic and therapeutic considerations

Ten dialysis-treated patients with hypercalcemia (11.5 +/- 0.3 mg/dl, mean +/- SE) due to renal osteodystrophy were compared with 30 control dialysis-treated patients who were not hypercalcemic (9.5 +/- 0.1 mg/dl). The hypercalcemic patients were more disabled than the control patients. Fifty percent of the hypercalcemic patients and 37 percent of the control patients had a mineralization defect (p greater than 0.6). In the control group, intact parathyroid hormone level was significantly higher in patients with osteitis fibrosa than in those with osteomalacia (247 +/- 39 pg/ml versus 60 +/- 20 pg/ml, respectively, p less than 0.005) whereas in the hypercalcemic patients, parathyroid hormone measurements did not discriminate between these two types of bone disease. Osteomalacia was more severe and bone aluminum staining was stronger in the hypercalcemic patients than in the control patients (2.02 +/- 0.47 versus 0.35 +/- 0.11 mm/mm2 tissue area, p less than 0.001). The mean serum calcium level fell from 11.2 +/- 0.2 mg/dl to 10.5 +/- 0.3 mg/dl (p less than 0.01) in eight hypercalcemic patients treated with 24,25-dihydroxyvitamin D. It is concluded that hypercalcemia in patients undergoing dialysis is associated with an increase in bone aluminum level, and with more severe osteomalacia. Intact parathyroid hormone levels are useful for predicting bone histomorphometric parameters but only when hypercalcemia is not present. The drug, 24,25-dihydroxyvitamin D, was effective in lowering the serum calcium level.

Parathyroid hormone response to hypocalcemia in hemodialysis patients with osteomalacia

The parathyroid hormone response to hypocalcemia was investigated in hemodialysis patients with osteomalacia and compared to those with osteitis fibrosa. Hypocalcemia was induced during hemodialysis by employing a dialysate devoid of calcium. Patients with osteomalacia had a blunted maximum amino terminal parathyroid hormone response (+/- SD) (0.39 +/- 0.33 vs. 0.87 +/- 0.53 ng/ml, P less than 0.05) and maximum carboxy terminal parathyroid hormone response (+/- SD) (0.36 +/- 0.20 vs. 0.84 +/- 0.47, P less than 0.02) to hypocalcemia. The decline in plasma calcium was greater in patients with osteomalacia at 90 (P less than 0.05), 120 (P less than 0.01), and 150 min (P less than 0.01). In osteomalacia patients the surface density of histologically detectable trabecular bone aluminum correlated directly with the percent relative osteoid volume (P less than 0.005) and inversely with the maximum amino terminal parathyroid hormone response to hypocalcemia (P less than 0.025). These results suggest that hemodialysis patients with osteomalacia have diminished secretion of parathyroid hormone and a decreased ability to restore plasma calcium homeostasis during hypocalcemia.

Vitamin D metabolism during recovery from severe osteitis fibrosa cystica of primary hyperparathyroidism

Serum concentrations of 1,25-dihydroxyvitamin D [1,25-(OH)2D] and immunoreactive parathyroid hormone were measured before and for 7 months after the removal of a 15-g parathyroid adenoma from a 44-yr-old woman with primary hyperparathyroidism and severe osteitis fibrosa cystica. Despite the fall in parathyroid hormone levels from preoperative levels of 20 to 1--2 ng/ml after surgery (normal, up to 1.2 ng/ml), serum 1,25-(OH)2D concentrations remained markedly elevated (156 pg/ml) preoperatively; 124 pg/ml 17 weeks postoperative), approaching the normal range (18--56 pg/ml) only after 5 months (65 pg/ml). Hypocalcemia and hypophosphatemia persisted despite oral 1,25-(OH)2D3 (1 and 2 micrograms/day) and large doses of (oral and iv) calcium gluconate (up to 30 g/day). Healing of the skeletal lesions, reversal of the myopathy, and return of 1,25-(OH)2D circulating levels to normal corresponded to the time when serum phosphate became normal. The stimulus for the persistently elevated serum 1,25-(OH)2D levels may have been hypocalcemia per se, low serum phosphate, or an unidentified signal that paralleled serum phosphate, as serum PTH levels remained in the upper normal range throughout the recovery period.

Dialysate calcium levels, dialysis hours and the healing of osteitis fibrosa

Unselected patients receiving intermittent haemodialysis at home were examined by hand radiographs to study the progression of osteitis fibrosa. Patients were using Kiil dialysers and Drake-Willock proportioning systems. The calcium phosphorus product was controlled by an adequate dialysis schedule supplemented by aluminum hydroxide gel. Dialysate calcium ranged between 5.7 and 7.3 mg/100 ml depending on the calcium content of local tap water. In 73 percent of patients the osteitis fibrosa improved radiologically and in most patients complete healing occurred. The rate of change was slow. Patients whose bones healed had significantly higher serum and tap water calcium levels than those whose bones deteriorated. There was no significant difference in the serum phosphorus levels in the two groups. Improvement of osteitis fibrosa requires both control of calcium phosphorus product and suppression of the parathyroid gland. Long dialysis hours with a positive calcium balance during dialysis were necessary to achieve the best results.

[Diagnosis of an osseous form of hyperparathyroidism]

Under observation were 66 (50.3%) of 130 patients with an ossific form of hyperparathyroidism. Fourty five patients showed the classical picture of Recklinghausen disease, and 21-only diffuse osteoporosis. The correct diagnosis would be established 4-5 years following the onset of the disease. During the period of most distinct manifestations pains in bones were noted in 93 per cent of cases. Two thirds of patients showed marked atonia and fatigue. Pathological fractures were multiple and were observed in 45 of 66 patients (totally 125 fractures). Great importance in establishing the diagnosis of the form of hyperparathroidism is attached to roentgenological investigation of all bones and biochemical assay of blood and urine.

Plasma magnesium concentration in primary hyperparathyroidism

The plasma magnesium concentration has been determined in 73 patients with primary hyperparathyroidism. In most patients it lay within the normal range (1.7-2.3 mg./100 ml.), but in five it was less than 1.6 mg./100 ml. These patients had relatively high urinary magnesium outputs, and one of them, studied in greater detail, failed to retain parenterally administered magnesium. Hence hypomagnesaemia in hyperparathyroidism may be associated with a defect in renal magnesium conservation, which may be reversible.