Clinical approach to clarifying the mechanism of abnormal bone metabolism in McCune-Albright syndrome

Bone tumours around the elbow: a rare entity

Bone tumours around the elbow are rare. Even nowadays diagnostic dilemmas and delays are common. During recent decades the management and prognosis of patients with elbow bone tumours has improved significantly.Benign tumours can be treated using minimally invasive procedures, whereas malignant ones require a multidisciplinary team approach based on an adjuvant therapeutic regimen of chemotherapy, radiotherapy and limb salvage procedures.This article reviews the most commonly encountered elbow bone tumours and their management. Cite this article: EFORT Open Rev 2019;4:133-142. DOI: 10.1302/2058-5241.4.180086.

Zoledronate Therapy for the Pathological Humeral Fracture in Polyostotic Fibrous Dysplasia: A Case Report

Fibrous dysplasia (FD) of bone is a rare skeletal disease often associated with bone pain, deformities and fractures. The bisphosphonate therapies are reported to be useful for bone pain, but seem to be not suitable for fracture repairs of extremities. This is the first report of zoledronate-induced radiological improvement and long bone fracture union in polyostotic FD. A 30-year-old Japanese female had bilateral shepherd's crook deformities typical to FD and right pathological femoral fracture and left humeral fracture nonunion. These fractures occurred without major traumas and the humeral fracture was not united for 1 year with conservative therapy. Laboratory blood test results were notable for elevated serum alkaline phosphatase and urine N-terminal cross-linking telopeptide of type I collagen. Her subtrochanteric femoral fracture was percutaneously fixed using Kirschner wires. After surgery, a hip spica cast was applied for 2 months and the orthosis for the next 2 months. Bony union of the femoral fracture was observed 5 months after surgery. Increased bone turnover and typical radiological features suggested that the constant elbow pain was due to both FD itself and humeral nonunion. Considering the possible side effects of zoledronate delaying acute fracture healing, we initiated zoledronate (Zometa(®); Novartis, Tokyo, Japan) therapy after femoral fracture union. Intravenous zoledronate acid was administered at a dose of 2 mg, along with supplementation of calcium (600 mg/day) and vitamin D (alfacalcidol 0.5 μg/day) to limit the risk of osteomalacia and improve the efficacy of bisphosphonate therapy. The patient's elbow pain rapidly resolved 1 week after treatment. Second therapy with same dose was performed after 6 months. No recurrence of elbow pain was reported and bony union was diagnosed after 1 year from the first administration. This patient is currently doing well without recurrence of bone pain. She can also walk for a short distance with crutches. We presented the case of an FD patient with persistent elbow pain due to FD itself and nonunion of humeral fracture, which was ameliorated promptly by intravenous zoledronate therapies. This case illustrated the benefit of zoledronate treatment in patients with extensive polyostotic FD and pathological fractures of extremities.

Spinal polyostotic fibrous dysplasia in two adults: Does only biopsy unravel the mystery?

Polyostotic fibrous dysplasia is a rare non-inheritable genetic disease due to mutation in GNAS gene. Here we present two adults who were accidentally detected lytic lesions in spine and after extensive evaluation for malignancies; was diagnosed on biopsy. Current concept of the disease and management is discussed.

Alternative indications for bisphosphonate therapy

Bisphosphonates are currently used in the treatment of osteoporosis (postmenopausal and steroid-induced), hypercalcemia of malignancy, Paget's disease of bone, multiple myeloma, and skeletally related events associated with metastatic bone disease in breast, prostate, lung, and other cancers. There are, however, numerous other conditions where a decrease in bone remodeling by bisphosphonates might aid in disease management. The focus of this review will be to discuss a select group of conditions for which bisphosphonate therapy may be efficacious. In this review we present several cases where bisphosphonates have been used as a primary or adjunctive treatment for giant cell lesions of the jaws. Use of bisphosphonate therapy for giant cell tumors of the appendicular skeleton, pediatric osteogenesis imperfecta, fibrous dysplasia, Gaucher's disease, and osteomyelitis will be discussed. Finally, we will review previous in vivo studies on the use of bisphosphonates to augment integration and to treat osteolysis surrounding failing orthopedic implants.

Phosphate: known and potential roles during development and regeneration of teeth and supporting structures

Inorganic phosphate (P(i)) is abundant in cells and tissues as an important component of nucleic acids and phospholipids, a source of high-energy bonds in nucleoside triphosphates, a substrate for kinases and phosphatases, and a regulator of intracellular signaling. The majority of the body's P(i) exists in the mineralized matrix of bones and teeth. Systemic P(i) metabolism is regulated by a cast of hormones, phosphatonins, and other factors via the bone-kidney-intestine axis. Mineralization in bones and teeth is in turn affected by homeostasis of P(i) and inorganic pyrophosphate (PPi), with further regulation of the P(i)/PP(i) ratio by cellular enzymes and transporters. Much has been learned by analyzing the molecular basis for changes in mineralized tissue development in mutant and knock-out mice with altered P(i) metabolism. This review focuses on factors regulating systemic and local P(i) homeostasis and their known and putative effects on the hard tissues of the oral cavity. By understanding the role of P(i) metabolism in the development and maintenance of the oral mineralized tissues, it will be possible to develop improved regenerative approaches.

McCune-Albright syndrome with acromegaly and fibrous dysplasia associated with the GNAS gene mutation identified by sensitive PNA-clamping method

A 16-year-old girl presented with McCune-Albright syndrome associated with acromegaly and fibrous dysplasia. Brain MRI demonstrated a pituitary tumor. X-ray films showed bone deformities, and 99TmO4 bone scintigraphy revealed increased uptake of radioactivity in the affected bones. Although the serum FGF23 level was increased, the serum calcium, phosphate, and active vitamin D levels were all within normal limits. GNAS gene mutation was detected at neither codon 201 nor 227 by conventional PCR-based direct sequencing analysis. We performed a selective PCR with peptide nucleic acid (PNA) clamping to increase the sensitivity for gene mutation detection and identified the R201C GNAS mutation.

Metabolic Bone Disease in Children

Metabolic bone disease in children includes many hereditary and acquired conditions of diverse etiology that lead to disturbed metabolism of the bone tissue. Some of these processes primarily affect bone; others are secondary to nutritional deficiencies, a variety of chronic disorders, and/or treatment with some drugs. Some of these disorders are rare, but some present public health concerns (for instance, rickets) that have been well known for many years but still persist. The most important clinical consequences of bone metabolic diseases in the pediatric population include reduced linear growth, bone deformations, and non-traumatic fractures leading to bone pain, deterioration of motor development and disability. In this article, we analyze primary and secondary osteoporosis, rickets, osteomalacia (nutritional and hereditary vitamin D-dependent, hypophosphatemic and that due to renal tubular abnormalities), renal osteodystrophy, sclerosing bony disorders, and some genetic bone diseases (hypophosphatasia, fibrous dysplasia, skeletal dysplasia, juvenile Paget disease, familial expansile osteolysis, and osteoporosis pseudoglioma syndrome). Early identification and treatment of potential risk factors is essential for skeletal health in adulthood. In most conditions it is necessary to ensure an appropriate diet, with calcium and vitamin D, and an adequate amount of physical activity as a means of prevention. In secondary bone diseases, treatment of the primary disorder is crucial. Most genetic disorders await prospective gene therapies, while bone marrow transplantation has been attempted in other disorders. At present, affected patients are treated symptomatically, frequently by interdisciplinary teams. The role of exercise and pharmacologic therapy with calcium, vitamin D, phosphate, bisphosphonates, calcitonin, sex hormones, growth hormone, and thiazides is discussed. The perspectives on future therapy with insulin-like growth factor-1, new analogs of vitamin D, strontium, osteoprotegerin, and calcimimetics are presented.