Cervical spine tenosynovial giant cell tumor involving the atlantoaxial joint in a pediatric patient with medulloblastoma.

Tenosynovial giant cell tumor (TGCT) is a benign condition that arises from tendon sheaths, synovium, or bursae and is classified according to the site of involvement (intra-articular versus extra-articular) and pattern of growth (localized versus diffuse). The diffuse form tends to present as peri-articular masses and are locally aggressive. It usually presents as a mono-articular process affecting larger joints. Spinal involvement is extremely rare, particularly the cervical spine. In this case report, we present a pediatric case of spinal TGCT involving the C1-C2 joint which was incidentally detected in a 13-year-old girl undergoing surveillance for medulloblastoma recurrence. Although spinal TGCT is a benign condition, it remains a diagnostic challenge, which specific to our case can raise the concern for malignancy or metastasis. We also described a percutaneous biopsy approach using a spring-loaded blunt tip coaxial needle to avoid inadvertent vascular injury. The imaging features of spinal TGCT and biopsy approach for atlantoaxial lesion are discussed together with a comprehensive review of the literature.

Osteolipoma in the Forearm.

A case of left distal forearm and wrist osteolipoma in a 56 year old female is reported. The patient presented with a 3 year history of nontender left wrist mass. Radiographs demonstrated a lobulated mass of mixed low density and calcifications, not adjacent to and with no connection to underlying bone. Ultrasound showed a spheroid hyperechoic lesion with internal heterogeneity and rim of calcifications. Magnetic resonance imaging revealed a lesion with predominantly fat characteristics on T1 weighted and T2 weighted sequences, with rim of peripheral calcification and specks of internal calcification. Histological examination after excision of the mass showed the lesion to be an osteolipoma. Osteolipoma is a rare variant of lipoma with osseous metaplasia and should be considered in the differential of a fat containing mass with ossification.

Can pre-operative axial CT imaging predict syndesmosis instability in patients sustaining ankle fractures? Seven years' experience in a tertiary trauma center.

OBJECTIVE: The purpose of this study is to explore the diagnostic accuracy of CT measurements in predicting syndesmosis instability of injured ankle, with correlation to operative findings. METHODS: From July 2006 to June 2013, 123 patients presented to a single tertiary hospital who received pre-operative CT for ankle fractures were retrospectively reviewed. All patients underwent open reduction and internal fixation for fractures and intra-operative syndesmosis integrity tests. The morphology of incisura fibularis was categorized as deep or shallow. The tibiofibular distance (TFD) between the medial border of the fibula and the nearest point of the lateral border of tibia were measured at anterior (aTFD), middle (mTFD), posterior (pTFD), and maximal (maxTFD) portions across the syndesmosis on axial CT images at 10 mm proximal to the tibial plafond. Statistical analysis was performed with independent samples t test and ROC curve analysis. Intraobserver reproducibility and inter-observers agreement were also evaluated. RESULTS: Of the 123 patients, 39 (31.7%) were operatively diagnosed with syndesmosis instability. No significant difference of incisura fibularis morphology (deep or shallow) and TFDs was demonstrated respective to genders. The axial CT measurements were significantly higher in ankles diagnosed with syndesmosis instability than the group without (maxTFD means 7.2 ± 2.96 mm vs. 4.6 ± 1.4 mm, aTFD mean 4.9 ± 3.7 mm vs. 1.8 ± 1.4 mm, mTFD mean 5.3 ± 2.4 mm vs. 3.2 ± 1.6 mm, pTFD mean 5.3 ± 1.8 mm vs. 4.1 ± 1.3 mm, p < 0.05). Their respective cutoff values with best sensitivity and specificity were calculated; the aTFD (AUC 0.798) and maxTFD (AUC 0.794) achieved the highest diagnostic accuracy. The optimal cutoff levels were aTFD = mm (sensitivity, 56.4%; specificity, 91.7%) and maxTFD = 5.65 mm (sensitivity, 74.4%; specificity, 79.8%). The inter-observer agreement was good for all aTFD, mTFD, pTFD, and maxTFD measurements (ICC 0.959, 0.799, 0.783, and 0.865). The ICC for intraobserver agreement was also very good, ranging from 0.826 to 0.923. CONCLUSIONS: Axial CT measurements of tibiofibular distance were useful predictors for syndesmosis instability in fractured ankles. The aTFD and maxTFD are the most powerful parameters to predict positive operative instability.

Diagnostic power of various computed tomography signs in diagnosing acute appendicitis.

OBJECTIVE: To review the diagnostic power of various computed tomography (CT) signs in acute appendicitis, in particular those initially classified as inconclusive. MATERIALS AND METHODS: Retrospective review of 100 CT abdomen and pelvis studies with assessment of maximal luminal diameter, wall thickness and cross-sectional diameter of the appendix, periappendiceal inflammatory changes, and presence of appendicolith. RESULTS: All CT signs show statistically significant occurrences in acute appendicitis. Their respective cut-off values with best sensitivity and specificity were calculated. Those from the inconclusive cases were also reviewed. CONCLUSION: Maximal cross-sectional diameter of the appendix is the most powerful parameter. Rest of the CT signs is supportive, especially in cases with inconclusive results.

Reducing radiation exposure from computed tomography of the brain in children--report of a practical approach.

PURPOSE: To reduce radiation exposure to paediatric neurosurgical patients from computed tomography (CT), a CT scanning protocol - lower radiation dose and selective scan segment (LDSS) protocol was used for CT brain at the authors' hospital. To evaluate the amount of reduction in radiation exposure by using this LDSS protocol compared to their usual protocol, the authors prospectively documented their findings. METHODS: From May 2010 to June 2011, paediatric neurosurgical patients requiring CT brain, and when it was not a clinical emergency and there was baseline CT or MRI brain available, were evaluated for the LDSS protocol. The LDSS protocol used a lower tube current-time product and a shorter scan length to attain a lower total radiation dose. The CT scanning parameters of the patients' usual CT brain and LDSS CT were recorded and compared. Adverse events were also recorded. RESULTS: A total of 24 paediatric patients were included. Using the LDSS protocol, the effective doses were between 9% and 80% of the usual protocol and, in 20 patients, ≤50% of the usual protocol. The tube voltage was 120 kV. For patients below 10 years old, 100 mA s was adequate for the purposes of their CTs; in some patient categories, it was lower than 100 mA s. For patients aged 10 or above, 150 mA s was used. The scan length varied. CONCLUSIONS: Radiation exposure from CT brain in paediatric neurosurgical patients could be reduced by adopting a CT scanning protocol, which aimed dynamically at a lower tube current-time product and a shorter scan length than the usual settings at a hospital.

Forward shifting of posterior dural sac during flexion cervical magnetic resonance imaging in Hirayama disease: an initial study on normal subjects compared to patients with Hirayama disease.

OBJECTIVE: Forward shifting of the posterior cervical dural sac is the most important sign in diagnosing Hirayama disease but can also be seen in normal subjects, causing potential diagnostic dilemma. We aim to explore the degree of forward displacement of posterior dural sac in normal subjects compared to that with Hirayama disease. MATERIALS AND METHODS: 50 healthy male teenagers and 3 patients with Hirayama disease were recruited into the control group and patient group, respectively. MR imaging of the cervical spine was performed in both neutral and flexion positions for all subjects, with the following parameters measured: maximal distance of forward shifting of posterior dural sac, dimension of dural sac and spinal cord. RESULTS: Forward shifting of the posterior cervical dural sac was depicted in 46% of normal subjects upon flexion position but without associated cord compression due to intrinsic expansion of the spinal canal volume. This intrinsic compensatory mechanism was inadequate in diseased patients leading to cord compression with significant increment in ratio of anteroposterior diameter of forward displacement of posterior dural wall/anteroposterior diameter of spinal canal ("x/y"), and decrement in ratio of anteroposterior diameter of spinal cord/perpendicular transverse diameter of spinal cord ("a/b"). CONCLUSION: Depicting of forward shifting of posterior dural sac alone on flexion position cannot reliably diagnose Hirayama disease, which should be established only if there is forward shifting of posterior dural sac, plus increased ratio of x/y and decreased ratio of a/b on flexion position from associated mass effect on the spinal cord.

Redistribution of hematoma to spinal subdural space as a mechanism for the rapid spontaneous resolution of posttraumatic intracranial acute subdural hematoma: case report.

BACKGROUND: Rapid spontaneous resolution of posttraumatic intracranial ASDH has been reported in the literature since 1986. We report a case to demonstrate that redistribution of hematoma to the spinal subdural space is a mechanism for the rapid spontaneous resolution of posttraumatic intracranial ASDH. CASE DESCRIPTION: A 73-year-old woman with a slipped-and-fell injury had a worst GCS score of 8/15. Computerized tomography of the brain demonstrated a large intracranial ASDH with mass effect. Conservative management was decided because of her poor premorbid general condition. Rapid clinical improvement was observed within 5 hours after the CT. Progress CT of the brain at 45 hours postinjury showed that the size of the intracranial ASDH was markedly diminished. The CT findings apparently demonstrated a caudal distribution of the intracranial ASDH over the tentorium and then into the posterior fossa. To investigate this further, an MRI of the spine was performed, which showed that there was spinal SDH in the cervical and thoracic spine. CONCLUSION: This is the first report demonstrating that redistribution of posttraumatic intracranial ASDH to the spinal subdural space is one of the mechanisms behind the rapid spontaneous resolution of posttraumatic intracranial ASDH in the acute phase.

Femoral facial syndrome with bilateral agenesis of femora and preaxial polydactyly of the feet in a Chinese stillborn.

A female Chinese stillborn with clinical characteristics of femoral facial syndrome is described. Apart from the typical facial features of the syndrome like short nose with broad tip, up-slanting palpebral fissures, cleft lip and cleft palate, micrognathia, and bilateral hypoplastic and malformed pinnae, the case had two rare findings, complete absence of both femora, and preaxial polydactyly in the feet. The combination of these two findings in a single patient had not been reported before. This report also reiterates the rare association between preaxial polydactyly and the femoral facial syndrome.

Spinal aneurysmal bone cyst causing acute cord compression without vertebral collapse: CT and MRI findings.

Aneurysmal bone cyst (ABC) of the spine can cause acute spinal cord compression in young patients. We report the CT and MRI findings in a histology-proven case of spinal ABC presenting with sudden paraplegia. Typical features of a spinal ABC at the thoracic level with considerable extension into the posterior epidural space and cord compression were demonstrated. Special note was made of the disproportionately large longitudinal extent of the epidural component of the lesion. Associated vertebral collapse was absent. A fracture of the overlying cortex had probably allowed the lesion to decompress and track along the epidural space without significantly jeopardizing integrity of the osseous structures. This case illustrates a less frequently recognised mechanism of acute spinal cord compression by ABC.