Osteomalacia oncogénica secundaria a tumor mesenquimal fosfatúrico del pie / Oncogenic osteomalacia secondary to phosphaturic mesenchymal tumour of the foot

RESUMEN La osteomalacia oncogénica es un síndrome metabólico paraneoplásico caracterizado por hipofosfatemia debida a la pérdida renal de fosfato, con nivel bajo de vitamina D. Este trastorno está asociado con la liberación de factores fosfatúricos por células tumorales, especialmente el factor de crecimiento fibrolástico 23 (FGF23). Las neoplasias relacionadas con la osteomalacia oncogénica suelen ser tumores pequeños de linaje mesenquimatoso y pueden ser difíciles de localizar en algunos casos debido a su tamaño y ubicación poco accesible al examen físico. Presentamos a un paciente que desarrolló fracturas vertebrales y de cadera debido a osteomalacia oncogénica asociada con un tumor mesenquimatoso fosfatúrico del tejido graso profundo de la planta del pie, que finalmente se diagnosticó después de 3 años del inicio de los síntomas, cuando el tumor pudo ser localizado por el rastreo gammagráfico óseo con pentatreótido marcado con indio-111 y por las imágenes de resonancia magnética nuclear.

ABSTRACT Oncogenic osteomalacia is a paraneoplastic metabolic syndrome characterised by a low phosphates in the blood due to renal phosphate losses with inadequately normal or low vitamin D levels. This disorder is associated with the release of tumour cell-secreted phosphaturic factor, most notably fibroblast growth factor 23 (FGF-23). The neoplasms related to oncogenic osteomalacia are usually small tumours of mesenchymal lineage, and they may be difficult to locate in the physical examination in some cases, due to their size and inaccessible location. The case is presented of a patient who developed vertebral and hip fractures due to oncogenic osteomalacia associated with a phosphaturic mesenchymal tumour of the deep fat tissue in the sole of the foot. This was finally diagnosed after 3 years of the onset of symptoms after being located by bone scintigraphy with Indium-111 labelled pentetreotide and magnetic resonance imaging.

Hypophosphataemic rickets/osteomalacia: A descriptive analysis.

Background & objectives: Hypophosphataemic rickets/osteomalacia (HRO) is an uncommon metabolic bone disorder which affects all ages and either sex. It is characterized by low concentration of serum phosphate levels leading to impairment of mineralization of bone matrix with variable aetiology. We present clinical profile and treatment outcome of 17 patients of HRO. Methods: Seventeen consecutive patients (8 were < 18 yr of age, with median age of presentation being 27.5 yr) of HRO who came to the department of Endocrinology in a tertiary care hospital in north India from January 2000 to December 2006 were included in the present study. Their aetiology, clinical features, biochemical parameters, radiographic features, treatment and outcome were analyzed. Results: HRO was commoner in females (70.5%) with positive family history observed in 6 (35.3%) patients. Common presenting features were short stature (58.8%), backache (58.8%), bony deformities (58.8%), joint pain (52.9%), fractures (29.4%) and dental abnormalities (23.5%). Radiological abnormalities noted were generalized bony deformities (58.8%), fractures (29.4%), and pseudo fractures (17.6%). Mesenchymal tumours were localized in the pelvis in one patient and in the right jaw in another. The patients were treated with calcium (elemental calcium 1 g/d) and oral phosphate supplements (dose 30 – 50mg/kg/day in divided doses) along with active vitamin D supplements (dose 1- 3 μg/day) and followed up for a mean of 2 yr. Two patients also received growth hormone (GH) therapy in the dose of 2U/day for 6 and 18 months respectively. Symptomatic well being was reported by all the patients and improvement was noted in the levels of phosphate (P<0.005) and alkaline phosphatase (P<0.05) after treatment. Interpretation & Conclusions: A diagnosis of HRO should be considered in all patients presenting with short stature, deformities or musculoskeletal pains along with low serum phosphate with normal iPTH and 25 – hydroxy vitamin D.

Oncogenic osteomalacia, you say? better start looking then - a case report

Tumour-induced or oncogenic osteomalacia (OOM) is a rare paraneoplastic syndrome characterized by bone pain and muscle weakness. A biochemical profile consisting of normocalcaemia, hypophosphataemia, phosphaturia, increased serum alkaline phosphatase and inappropriately low serum levels of 1, 25-dihydroxyvitamin-D is diagnostic. OOM is usually caused by an osseous or soft-tissue tumour of mesenchymal origin that secretes phosphaturic substances leading to increased urinary phosphate wasting. These tumours are small and slow growing. The diagnosis continues to be easily missed and when eventually made, localization of the tumour can be difficult. We describe the case of a young man who presented with severe generalized pain associated with muscle weakness. He was extensively investigated and eventually diagnosed to have OOM 3 years after initial presentation. Specialized investigations were necessary to localize the offending tumour.