| Tumor-induced osteomalacia is due to renal phosphate wasting in response to a humoral factor produced by a tumor, usually a benign mesenchymal tumor. Removal of the tumor is followed by resolution of the metabolic disorder. physicians should be aware that sporadic renal phosphate wasting in an adult should prompt a search for a tumor. A case of tumor-induced osteomalacia due to a nonossifying fibroma of the radius is reported. After removal of the tumor, renal phosphate excretion returned to normal, but the patient developed tertiary hyperparathyroidism. Eight years elapsed between symptom onset and the diagnosis of the tumor. The pathogenesis of tumor-induced osteomalacia and the role of treatment for renal phosphate wasting on the subsequent development of hyperthyroidism are discussed. ( info) |
2/329. Oncogenic osteomalacia presenting as bilateral stress fractures of the tibia. We report on a patient with bilateral stress fractures of the tibia who subsequently showed classic biochemical features of oncogenic osteomalacia. Conventional radiographs were normal. MR imaging revealed symmetric, bilateral, band-like low-signal lesions perpendicular to the medial cortex of the tibiae and corresponding to the only lesions subsequently seen on the bone scan. A maxillary sinus lesion was subsequently detected and surgically removed resulting in prompt alleviation of symptoms and normalization of hypophosphatemia and low 1,25-(OH)2 vitamin D3. The lesion was pathologically diagnosed as a hemangiopericytoma-like tumor. patients with oncogenic osteomalacia may present with stress fractures limited to the tibia, as seen in athletes. The clue to the real diagnosis lies in paying close attention to the serum phosphate levels, especially in patients suffering generalized symptoms of weakness and not given to unusual physical activity. ( info) |
3/329. Lambda light chain induced nephropathy: a rare cause of the fanconi syndrome and severe osteomalacia. The fanconi syndrome is a generalized disorder of proximal renal tubular transport characterized by wasting of phosphate, amino acids, glucose, bicarbonate, and uric acid. The association of the acquired fanconi syndrome with lambda light-chain proteinuria is rare. We report the third case in the English language literature. A 65-year-old man presented with severe pelvic pain. Investigations showed an elevated serum creatinine level, and a 24-hour urine collection contained 2.56 g protein. The fanconi syndrome was diagnosed, with findings of phosphaturia, glycosuria, and aminoaciduria. bence jones protein (lambda sub-type) was present in the urine at a concentration of 0.58 g/L. Monocytic cells in the bone marrow and proximal tubular cells in the kidney contained cytoplasmic crystalline inclusions. Undecalcified bone sections confirmed the clinical diagnosis of osteomalacia. The patient was treated with phosphate, calcium, and ergocalciferol and experienced significant symptomatic improvement. The fanconi syndrome caused by light-chain deposition in proximal tubular cells is well described in the literature. However, it is rare for the light chains to be of the lambda subtype. This may reflect differences in the physicochemical properties of kappa and lambda light chains. ( info) |
4/329. Musculoskeletal manifestations of osteomalacia: report of 26 cases and literature review. OBJECTIVE: This study was undertaken to describe the musculoskeletal manifestations in a selected population of 26 patients with biopsy-proven osteomalacia (OM) and provide a literature update. methods: The 26 patients with biopsy-proven OM were selected from a total number of 79 patients who underwent anterior iliac crest biopsy. The diagnosis of OM was confirmed by the presence of an osteoid volume greater than 10%, osteoid width greater than 15 microm, and delayed mineralization assessed by double-tetracycline labeling. RESULTS: OM was caused by intestinal malabsorption in 13 patients, whereas six other patients presented with hypophosphatemia of different causes. Five elderly patients presented with hypovitaminosis D, and in two patients the OM was part of renal osteodystrophy. Twenty-three patients presented with bone pain and diffuse demineralization, whereas three other patients had normal or increased bone density. Characteristic pseudofractures were seen in only seven patients. Six of the 23 patients with diffuse demineralization had an "osteoporotic-like pattern" without pseudofractures. Prominent articular manifestations were seen in seven patients, including a rheumatoid arthritis-like picture in three, osteogenic synovitis in three, and ankylosing spondylitis-like in one. Two other patients were referred to us with the diagnosis of possible metastatic bone disease attributable to polyostotic areas of increased radio nuclide uptake caused by pseudofractures. Six patients also had proximal myopathy, two elderly patients were diagnosed as having polymalgia rheumatica, and two young patients were diagnosed as having fibromyalgia. One of the patients who presented with increased bone density was misdiagnosed as possible fluorosis. CONCLUSION: OM is usually neglected when compared with other metabolic bone diseases and may present with a variety of clinical and radiographic manifestations mimicking other musculoskeletal disorders. ( info) |
5/329. Unusual combination of night blindness and optic neuropathy after biliopancreatic bypass. night blindness and optic neuropathy were the presenting symptoms of an iatrogenic malabsorption syndrome in a 64-year old female. This case illustrates the necessity of lifelong vitamin supplementation after biliopancreatic bypass for morbid obesity. ( info) |
6/329. Tumor-induced osteomalacia and symptomatic looser zones secondary to mesenchymal chondrosarcoma. Tumor-induced osteomalacia is a rare clinical entity that is associated with soft-tissue or skeletal tumors. We present a case report of a patient with a chest wall mesenchymal chondrosarcoma who presented with bone pain. The patient had skeletal changes in the femoral neck and fibula consistent with osteomalacia and laboratory values suggesting phosphate diabetes. The patient was treated with tumor resection and phosphate supplementation with reversal of the signs and symptoms of osteomalacia. Tumor-induced osteomalacia is vitamin-D-resistant and often reversed by complete removal of the tumor. Most commonly, the causative tumors are of vascular, mesenchymal, or fibrous origin. The osteomalacia is associated with bone pain, muscle weakness, and radiographic changes. Tumor-induced humoral factors have been implicated in causing the osteomalacia, but the definite etiology has yet to be determined. Current treatment includes complete tumor resection and electrolyte supplementation. ( info) |
| A 49 year-old Japanese woman had subjected enlargement of a cervical tumor, and also suffered two bone fractures in 2 years. The cervical tumor had enlarged further in the month prior to admission, becoming warm and tender. Endocrinological examination revealed that the serum intact PTH concentration was remarkably high at 400 pg/mL despite the low serum calcium concentration, and that the serum vitamin Ds concentration was decreased. Bone roentgenograms revealed severe osteolytic changes compatible with osteitis fibrosa cystica and a pathologic fracture of the humerus. Under a diagnosis of primary hyperparathyroidism, parathyroidectomy was performed, followed by fixation surgery for the pathologic fracture. Histologically, the cervical tumor was a parathyroid chief-cell adenoma with massive necrosis, and the bone pathology by iliac bone biopsy revealed the existence of osteomalacia. She was treated with calcium, vitamins D and K2 and calcitonin after the surgery. This case is a rare condition manifesting hypocalcemia with catastrophic osteoporosis under the coexistence of spontaneous infarction of parathyroid adenoma with osteomalacia, suggesting that the clinical features of hyperparathyroidism are modified by both the autoparathyroidiectomy and the existence of osteomalacia due to vitamin d deficiency. ( info) |
8/329. Post-gastrectomy bone disease undiagnosed for forty years. Polya partial gastrectomy was performed for peptic ulcer in a previously healthy woman aged 28 years. She complained afterwards of a variety of non-specific symptoms including weakness, tiredness, debility, slowness of walking, poor appetite and constipation. Within ten years her back became bent. She was treated for intercurrent hypertension and epilepsy. Bone fractures on low-impact trauma occurred in her fifties. At 57 years, she was unable to care for herself and had to be admitted to a nursing home. She could still walk slowly with the aid of a stick. For three months at the age of 65 years, she was unable to rise from her chair. Investigations disclosed severe post-gastrectomy bone disease. At no time had she complained of bone pains. ( info) |
| Oncogenic osteomalacia is a rare paraneoplastic syndrome characterized by hypophosphatemic osteomalacia due to renal phosphate wasting. The same biochemical features are found in patients with X-linked hypophosphatemic rickets/osteomalacia and sporadic hypophosphatemic osteomalacia with unknown etiology. Oncogenic osteomalacia is cured by resection of the responsible tumor. In contrast, patients with other types of hypophosphatemic rickets/osteomalacia need long-term treatment with large doses of active vitamin D3. Therefore, detection of the responsible tumor for oncogenic osteomalacia has great clinical importance. However, there is no standard method for detecting the tumor for oncogenic osteomalacia, and the responsible tumor is often very difficult to be found. We describe a patient with adult-onset osteomalacia due to renal phosphate wasting. Although oncogenic osteomalacia was suspected, cranial, chest, and abdominal computed tomography scanning, urological and otolaryngological examinations, and detailed palpation for soft tissue mass failed to detect the responsible tumor. However, magnetic resonance imaging skeletal survey revealed a tumor in the right femoral bone. Resection of the tumor resulted in normalization of serum phosphate and renal phosphate handling. Because the most frequent causes for oncogenic osteomalacia are tumors in bone or soft tissue, magnetic resonance imaging skeletal survey is a very powerful method for detecting the responsible tumor. Vigorous search for tumors with this method in patients with hypophosphatemic osteomalacia would be helpful not only for proper management of patients, but also for clarifying the identity of sporadic hypophosphatemic osteomalacia. ( info) |
| A 27-year-old woman with anorexia nervosa since adolescence was referred to our unit for generalized bone pain most severe at the pelvis and an inability to stand. She reported a pelvic fracture diagnosed one year earlier, which had failed to heal. Laboratory tests showed low serum phosphate, normal total serum calcium corrected for serum albumin, and very low urinary calcium excretion. Serum bone alkaline phosphatase and parathyroid hormone levels were elevated, whereas 25-hydroxy-vitamin D was severely decreased. Multiple vertebral and rib fractures were seen on plain radiographs. Radiographic images consistent with osteomalacia were pseudofractures of the left inferior pubic ramus, a bilateral complete fracture of the superior pubic ramus, and a characteristic pseudofracture (Looser zone) in the lateral margin of the right scapula. Vitamin D-deficient osteomalacia with secondary hyperparathyroidism was strongly suspected at this point, but it was decided not to confirm this diagnosis by bone biopsy with histomorphometry and osteoid labeling because of the emotional instability of the patient. Dual-energy X-ray absorptiometry disclosed severe demineralization. After two months on calcium and vitamin D supplements, the bone pain had abated and the patient was able to stand. Serum calcium had increased; serum phosphate, 25-hydroxy-vitamin D, and parathyroid hormone had returned to normal, and the pseudofractures showed evidence of healing. osteoporosis is a well-known complication of anorexia nervosa. This case shows that osteomalacia can also occur. Vitamin D status should be assessed in patients with long-standing severe anorexia nervosa. ( info) |