False-positive In-111 DTPA octreotide scintigraphy in bilateral tibial insufficiency fracture.

We present a case of bilateral tibial insufficiency fracture in which indium (In)-111 diethylenetriamine pentaacetic acid (DTPA) octreotide scan showed increased activity in the region of the fracture. The scan was performed in a 5-year-old girl with severe refractory hypertension and elevated plasma metanephrines for evaluation of possible neuroendocrine tumor. Octreotide scan is usually positive in neuroendocrine and some other tumors but also shows positive results in a number of other conditions. However insufficiency fracture has not been reported as a positive finding on octreotide scan in children. This may relate to the expression of somatostatin membrane receptor in activated white blood cells or expression of somatostatin receptors by bone cells.

Radiological Assessment and Outcome of Local Disease Progression after Neoadjuvant Chemotherapy in Children and Adolescents with Localized Osteosarcoma.

OBJECTIVE: We examined the interobserver reliability of local progressive disease (L-PD) determination using two major radiological response evaluation criteria systems (Response evaluation Criteria in Solid Tumors (RECIST) and the European and American Osteosarcoma Study (EURAMOS)) in patients diagnosed with localized osteosarcoma (OS). Additionally, we describe the outcomes of patients determined to experience L-PD. MATERIALS AND METHODS: Forty-seven patients diagnosed with localized OS between 2000 and 2012 at our institution were identified. Paired magnetic resonance imaging of the primary tumor from diagnosis and post-neoadjuvant chemotherapy were blindly assessed by two experienced radiologists and determined L-PD as per RECIST and EURAMOS radiological criteria. Interobserver reliability was measured using the kappa statistic (κ). The Kaplan Meier method and log-rank test was used to assess differences between groups. RESULTS: Of 47 patients (median age at diagnosis 12.9 years), 16 (34%) had L-PD (by RECIST or EURAMOS radiological definition). There was less agreement between the radiologists using EURAMOS radiological criteria for L-PD (80.9%, κ = 0.48) than with RECIST criteria (97.9%, κ = 0.87). Patients with radiologically defined L-PD had a 5-year progression-free survival (PFS) of 55.6%, compared to a 5 year-PFS of 82.7% in the group of patients without L-PD (n = 31) (Log rank p = 0.0185). CONCLUSIONS: The interobserver reliability of L-PD determination is higher using RECIST than EURAMOS. RECIST can be considered for response assessment in OS clinical trials. The presence of L-PD was associated with worse outcomes.

Imaging of pediatric musculoskeletal infection.

Musculoskeletal infections in children present a diagnostic challenge because they are difficult to recognize in the early stages of the disease and can be confused with other pathology such as tumors or trauma. The severity of disease may be associated with the primary tissue of involvement with bone greater than joint, greater than muscle, greater than soft tissue. The incidence of musculoskeletal infection is higher in infants and young children, and risk factors include premature birth, umbilical catheterization, urinary tract infection, immunodeficiency, and other preexisting disease. Neonates are at greater risk for infection with less virulent organisms due to immaturity of the immune system. The epidemiology of musculoskeletal infection is evolving, and the incidence of musculoskeletal infections in children, especially gram-positive infections, are increasing. Staphylococcus aureus continues to be the leading cause of musculoskeletal infection in children, and the emergence of resistant bacteria such as methicillin-resistant S. aureus is associated with a higher rate of complications. Atypical infections such as tuberculosis have also shown resurgence in the last few decades, whereas other infections such as Haemophilus influenzae are much less prevalent due to widespread immunization. Recent advances in earlier diagnosis and treatment help to reduce complications. However, even when musculoskeletal infection is successfully treated, there may be significant long-term effects on growth.