External auditory canal cholesteatoma: clinical and imaging spectrum

BACKGROUND AND PURPOSE: Cholesteatoma is an inflammatory lesion of the temporal bone that uncommonly involves the external auditory canal (EAC). In this large case series, we aimed to define its imaging features and to determine the characteristics most important to its clinical management. METHODS: Thirteen cases of EAC cholesteatoma (EACC) were retrospectively reviewed. Clinical data were reviewed for the history, presentation, and physical examination findings. High-resolution temporal bone CT scans were examined for a soft-tissue mass in the EAC, erosion of adjacent bone, and bone fragments in the mass. The middle ear cavity, mastoid, facial nerve canal, and tegmen tympani were evaluated for involvement. RESULTS: Patients presented with otorrhea, otalgia, or hearing loss. Eight cases were spontaneous, and five were postsurgical or post-traumatic. CT imaging in all 13 cases showed a soft-tissue mass with adjacent bone erosion. Intramural bone fragments were identified in seven cases. This mass most often arose inferiorly (n = 8) or posteriorly (n = 8), but it was circumferential in two cases. We noted middle ear extension (n = 5), mastoid involvement (n = 4), facial canal erosion (n = 2), and tegmen tympani dehiscence (n = 1). CONCLUSION: Temporal bone CT shows EACC as a soft-tissue mass within the EAC, with adjacent bone erosion. Bone fragments may be present within the mass. The cholesteatoma may extend into the mastoid or middle ear, or it may involve the facial nerve canal or tegmen tympani. Recognition of this entity and its possible extension is important because it may influence clinical management.     

Influence of gravity on radiographic contrast material-based measurements of regional blood flow distribution

RATIONALE AND OBJECTIVES: Radiographic measurement of regional blood flow distribution in the lungs is potentially biased because the contrast material used to track flow is denser than blood. The authors performed this study to evaluate the effect of gravity on flow estimates by using an experimental test phantom and numeric simulations. MATERIALS AND METHODS: Cross-sectionally uniform boluses of radiopaque contrast material were delivered at the upstream end of a horizontal inlet tube connected to a downstream axisymmetric bifuration attached to collecting tubing spirals. The phantom was imaged by using both planar angiography and dynamic multi-detector row computed tomography (CT) during the passage of the bolus through the phantom. The images were analyzed to determine the relative amounts of contrast material traveling through the top and bottom branches of the bifurcation by using varying Reynolds numbers and ratios of inlet tube volume to bolus volume. Numeric simulations of flow within a straight channeL with use of a dispersion operator intended to simulate settling of the bolus due to gravity, were performed under conditions representative of those in the experiments. RESULTS: When the plane of the bifurcation was vertical and actual flow through the two branches was equal, the fraction of contrast material passing through the downward-directed branch increased with decreasing Reynolds number and increasing inlet tube-bolus volume ratio. This occurred in both the experiments and the simulations. CONCLUSION: Because in the circulation Reynolds number decreases and pathway length increases with decreasing vessel diameter, the accuracy of regional flow measurements obtained with angiography or CT within the lungs may be limited by density differences between contrast material and blood.     

Macroscopic Quality Control Improves the Reliability of Blue Dye–Only Sentinel Lymph Node Biopsy in Breast Cancer

Background: One of the problems of sentinel lymph node (SLN) biopsy is the risk of false negatives. At the Institut Curie, to reduce the false-negative rate, we have developed a histological quality control of the SLN performed by blue dye alone, which consists of verification of the SLN blue stain by the pathologist.Methods: A total of 324 patients underwent an SLN biopsy procedure with patent blue dye only followed by an immediate axillary dissection. Initially, SLNs were checked to ensure that they were blue by macroscopic examination. Finally, a search for immunohistochemistry micrometastasis was performed.Results: In 277 (85.5%) of 324 patients, an SLN was identified by the surgeon. After standard examination, the false-negative rate was 11.1% (10 of 90). After macroscopic checking of the 197 negative SLNs, 167 of the 197 were confirmed blue, and there were 5 false negatives, which brought the false-negative rate down to 5.6% (5 of 90). Sixty SLNs out of the 167 confirmed blue SLNs were then proved to be immunohistochemically micrometastatic, and there were 3 false negatives, giving a final false-negative rate of 2.2% (2 of 90; P = .002).Conclusions: In this series, the procedure of pathologic analysis of the SLN has resulted in a significant reduction of the false-negative rate.     

The potential for telemedicine to improve coronary heart disease services

The potential of telemedicine to improve services for patients suffering from coronary heart disease (CHD) was explored. Key issues surrounding the delivery of CHD services in London were identified, such as a shortage of skilled staff, the need for appropriate patient information and problems with waiting times, particularly for diagnostic test results. Telemedicine has the potential to improve service delivery in each of these areas. It is unlikely that some of the targets for CHD service delivery set out by the Department of Health's National Service Frameworks can be met without the use of telemedicine.     

Effects of local blood flow on the percutaneous absorption of the organophosphorus compound malathion: a microdialysis study in man

Malathion [O,O-dimethyl-S-(1,2-dicarbethoxyethyl)phosphorodithioate] is an organophosphorus insecticide widely used in veterinary medicine and in humans for the treatment of lice. In this study, the rate of the percutaneous absorption of malathion has been measured in human skin, in vivo, using microdialysis. Malathion was detected in tissue dialysate within 30 min of its topical application to the skin of the volar surface of the forearm of healthy volunteers. The concentration of malathion in dialysate increased with lengthening duration of exposure to reach a steady state concentration at 2 h. Prolonged exposure to malathion caused a marked and long-lasting erythema localized to the area of contact. There was no evidence of local tissue oedema or of a neurogenically mediated flare or itch response following topical application. Reducing skin blood flow by the addition of the vasoconstrictor noradrenaline to the dialysis probe perfusate caused an eight-fold increase in the recovery of malathion in the dialysate, which failed to reach a steady state within 5 h. Together, these data confirm that malathion can be absorbed percutaneously and that its distribution within the cutaneous tissue space is influenced by local skin blood flow. They suggest that the increase in skin blood flow caused by malathion may itself play a significant role in enhancing its systemic uptake.     

Critical clinicopathologic analysis of 23 cases of fine-needle breast sampling initially recorded as false-positive. The 44-year experience of the Institut Curie

BACKGROUND: Because false-positive cytologic diagnoses in breast tumors are rare, few cases have been reported, although their consequences may be highly detrimental to the patient. The authors report the Institut Curie's experience, by using a multidisciplinary approach. METHODS: Of 9334 benign breast tumors examined preoperatively for cytologic diagnosis by fine-needle sampling (FNS), the 23 (0.25%) FNS cases considered to be false-positive were retrospectively reviewed and analyzed. RESULTS: Tumors were situated close to the nipple in 7 cases and away from the nipple in 16 cases. Tumor stage was T0 for 1 case, T1 for 18 cases, and T2 for 4 cases. Radiologically, six tumors were classified as malignant, seven as indeterminate or suspicious, and nine as benign. Three of six tumors studied by flow cytometry were DNA aneuploid. Based on a multidisciplinary clinicopathologic review, 20 FNS cases were finally classified as false-positive, and the remaining 3 tumors with malignant FNS and subsequent benign histology were classified as true-positive, because local and/or metastatic progression was observed in the short term. CONCLUSIONS: The authors' review suggests two categories of false-positive cases: the first in which cytologic benign patterns are overdiagnosed, and the second in which atypical morphologic criteria were present. Nevertheless, as shown by the malignant course in three cases, patients with malignant preoperative FNS and corresponding benign histology always require close clinical follow-up. Finally, surgical overtreatment rate could be decreased if all radiologically benign tumors with positive/suspicious FNS were subject to intraoperative frozen section examination.