We describe a case of oncogenic osteomalacia in an adult male who presented with low back pain and bilateral hip pain. Extensive investigations had failed to find a cause. A plain pelvic radiograph showed Looser's zones in both femoral necks. MRI confirmed the presence of insufficiency fractures bilaterally in the femoral head and neck. Biochemical investigations confirmed osteomalacia which was unresponsive to treatment with vitamin D and calcium. A persistently low serum phosphate level suggested a diagnosis of hypophosphataemic osteomalacia. The level of fibroblast growth factor-23 was highly raised, indicating the cause as oncogenic osteomalacia. This was confirmed on positron-emission tomography, MRI and excision of a benign fibrous histiocytoma following a rapid recovery. The diagnosis of oncogenic osteomalacia may be delayed due to the non-specific presenting symptoms. Subchondral insufficiency fractures of the femoral head may be missed unless specifically looked for.
"Due to a lack of knowledge the existence of the disease, the length of time from onset of symptoms until diagnosis is often long. As result, patients frequently present with multiple fractures, height loss, and generalized debilitated status, reminiscent of how patients in the past would present 2006, Tartaglia et al. 2006, Vandergheynst et al. 2006, Yoshioka et al. 2006, Ahn et al. 2007, Beech et al. 2007, Elston et al. 2007, Geller et al. 2007, Gershinsky et al. 2007, Halperin et al. 2007, Hesse et al. 2007a,b, Jacob et al. 2007, Kaul et al. 2007, Khosravi et al. 2007, Oka et al. 2007, Roarke & Nguyen 2007, Umphrey et al. 2007, Williams et al. 2007, van Boekel et al. 2008, Duet et al. 2008, Endo et al. 2008, von Falck et al. 2008, Habra et al. 2008, Hannan et al. 2008, Harish et al. 2008, Kenealy et al. 2008, Lewiecki et al. 2008, Mannstadt et al. 2008, Nasu et al. 2008, Ogura et al. 2008, Policarpio-Nicolas et al. 2008, Ratanasuwan et al. 2008, Vollbrecht & Rao 2008, Westerberg et al. 2008, Woznowski et al. 2008, Bahrami et al. 2009, Gore et al. 2009, Harbeck et al. 2009, Khadgawat et al. 2009, Mussig et al. 2009, Nawrot-Wawrzyniak et al. 2009, Pirola et al. 2009, Radaideh et al. 2009, Rendina et al. 2009, Romualdo-Silva et al. 2009, Savage & Zimmer 2009, Sciubba et al. 2009, Seijas et al. 2009, Szumera-Cieckiewicz et al. 2009, Uramoto et al. 2009, Woo et al. 2009, Yun et al. 2009, Chouhan et al. 2010, Dehghani et al. 2010, Haeusler et al. 2010, Ishii et al. 2010, Ito et al. 2010, Jagtap et al. 2010, Jung et al. 2010, Kobayashi et al. 2010, Kurien et al. 2010, Marshall et al. 2010, Mori et al. 2010, Pedrazzoli et al. 2010, Peters et al. 2010, Peterson et al. 2010, Xia et al. 2010). The fact that over 200 of these cases have been reported in the last 10 years indicates a growing recognition of this disease. "
[Show abstract][Hide abstract] ABSTRACT: Tumor-induced osteomalacia (TIO) is a rare and fascinating paraneoplastic syndrome in which patients present with bone pain, fractures, and muscle weakness. The cause is high blood levels of the recently identified phosphate and vitamin D-regulating hormone, fibroblast growth factor 23 (FGF23). In TIO, FGF23 is secreted by mesenchymal tumors that are usually benign, but are typically very small and difficult to locate. FGF23 acts primarily at the renal tubule and impairs phosphate reabsorption and 1α-hydroxylation of 25-hydroxyvitamin D, leading to hypophosphatemia and low levels of 1,25-dihydroxy vitamin D. A step-wise approach utilizing functional imaging (F-18 fluorodeoxyglucose positron emission tomography and octreotide scintigraphy) followed by anatomical imaging (computed tomography and/or magnetic resonance imaging), and, if needed, selective venous sampling with measurement of FGF23 is usually successful in locating the tumors. For tumors that cannot be located, medical treatment with phosphate supplements and active vitamin D (calcitriol or alphacalcidiol) is usually successful; however, the medical regimen can be cumbersome and associated with complications. This review summarizes the current understanding of the pathophysiology of the disease and provides guidance in evaluating and treating these patients. Novel imaging modalities and medical treatments, which hold promise for the future, are also reviewed.
Endocrine Related Cancer 04/2011; 18(3):R53-77. DOI:10.1530/ERC-11-0006 · 4.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Subchondral stress fractures of the femoral head may be either of the insufficiency-type with poor quality bone or the fatigue-type with normal quality bone but subject to high repetitive stresses. Unlike osteonecrosis, multiple site involvement rarely has been reported for subchondral stress fractures. We describe a case of multifocal subchondral stress fractures involving femoral heads and medial tibial condyles bilaterally within 2 weeks.
A 27-year-old military recruit began having left knee pain after 2 weeks of basic training, without any injury. Subsequently, right knee, right hip, and left hip pain developed sequentially within 2 weeks. The diagnosis of multifocal subchondral stress fracture was confirmed by plain radiographs and MR images. Nonoperative treatment of the subchondral stress fractures of both medial tibial condyles and the left uncollapsed femoral head resulted in resolution of symptoms. The collapsed right femoral head was treated with a fibular strut allograft to restore congruity and healed without further collapse.
There has been one case report in which an insufficiency-type subchondral stress fracture of the femoral head and medial femoral condyle occurred within a 2-year interval.
Because the incidence of bilateral subchondral stress fractures of the femoral head is low and multifocal involvement has not been reported, multifocal subchondral stress fractures can be confused with multifocal osteonecrosis. Our case shows that subchondral stress fractures can occur in multiple sites almost simultaneously.
Clinical Orthopaedics and Related Research 12/2011; 470(3):944-9. DOI:10.1007/s11999-011-2209-z · 2.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Bilateral insufficiency fractures of the proximal femur often have a pathological basis. Diagnosis of rare causes of insufficiency fractures can be challenging. Tumour-induced osteomalacia (TIO) is a rare paraneoplastic syndrome of mesenchymal tumours which leads to hypophosphataemia and osteomalacia. Suspected pathological fractures should be investigated thoroughly including a fasting serum phosphate level. Further investigations should include serum levels of fibroblast growth factor 23 (FGF23) which is a peptide hormone secreted by mesenchymal tumours. Available imaging modalities include Octreotide scanning which detects somatostatin receptors commonly expressed on mesenchymal tumours. After localisation and resection of the tumour, a full recovery from TIO is achievable.
Hip international: the journal of clinical and experimental research on hip pathology and therapy 04/2012; 22(2):227-9. DOI:10.5301/HIP.2012.9235 · 0.76 Impact Factor
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