Fibrosing mediastinitis mimicking malignancy at CT: negative FDG uptake in integrated FDG PET/CT imaging.
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Publications and source records attributed to Semin Chong.
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Histoplasmosis is the most common endemic mycosis in North America, and is followed by coccidioidomycosis and blastomycosis. Although the majority of these infections in immunocompetent persons are self-limited, some patients can develop severe pneumonitis or various forms of chronic pulmonary infection. Cryptococcoci, Aspergillus, Candidas, and Mucorals are ubiquitous organisms, which may affect immunocompromised patients. Specific imaging findings can be expected, depending on the organisms involved, underlying patients' conditions (immune status), and specific situations after immune depleting procedures.
OBJECTIVE: The purposes of our study were to determine the prevalence of mediastinal lymphadenopathy in idiopathic interstitial pneumonias, correlate their presence with high-resolution CT (HRCT) findings, and assess the potential value of mediastinal lymphadenopathy in the differential diagnosis of idiopathic interstitial pneumonias. MATERIALS AND METHODS: The study included 206 consecutive patients from three medical centers with pathologically proven idiopathic pulmonary fibrosis (n = 136), non-specific interstitial pneumonia (NSIP) (n = 47), cryptogenic organizing pneumonia (COP) (n = 16), respiratory bronchiolitis-interstitial lung disease (RB-ILD) (n = 5), and desquamative interstitial pneumonia (DIP) (n = 2). HRCT scans were retrospectively reviewed for the presence of mediastinal lymphadenopathy (short-axis diameter, >or= 10 mm), predominant parenchymal pattern, and extent of disease. RESULTS: Mediastinal lymphadenopathy was seen in 139 (67%) of 206 patients, including 90 (66%) of 136 with idiopathic pulmonary fibrosis, 38 (81%) of 47 with NSIP, six (38%) of 16 with COP, and five (71%) of seven with RB-ILD or DIP. The presence of enlarged nodes was less common in COP than in the other idiopathic interstitial pneumonias (p = 0.04). No significant difference was found in the prevalence of lymphadenopathy in patients with predominant ground-glass opacity (53%) or predominant reticulation (40%). The extent of parenchymal abnormalities was 25-50% in 74 patients (53%), 50-75% in 30 (22%), < 25% in 22 (16%), and > 75% in 13 (9%). A positive correlation between the extent of disease and presence of lymphadenopathy was seen in patients with NSIP (p = 0.01). CONCLUSION: Mediastinal lymphadenopathy is a common feature in idiopathic interstitial pneumonias, being slightly less common in COP than in the other idiopathic interstitial pneumonias. The presence of lymphadenopathy therefore has limited value in the differential diagnosis. In patients with idiopathic pulmonary fibrosis, the presence of lymph node enlargement did not correlate to any specific HRCT pattern or to the extent of disease.
OBJECTIVE: Our objective was to assess CT findings of tracheal metastasis of lung cancer. CONCLUSION: Tracheal metastasis of primary non-small cell lung cancer manifested as an endotracheal nodule or eccentric wall thickening of the trachea, showing contrast enhancement with a predilection for the upper trachea on CT. During postoperative evaluation of patients with surgically resected lung cancer, the possibility of tracheal metastasis of lung cancer should be suggested when an endotracheal nodule or eccentric wall thickening is present on CT.
OBJECTIVE: Thoracic actinomycosis is a chronic suppurative pulmonary or endobronchial infection caused by Actinomyces israelii, a gram-positive anaerobic organism. We present the CT features of thoracic actinomycosis with histopathologic correlation. CONCLUSION: The typical CT feature of parenchymal actinomycosis is a chronic segmental air-space consolidation containing necrotic low-attenuation areas with frequent cavity formation. A broncholith can be secondarily infected with Actinomyces organisms, resulting in endobronchial actinomycosis. It usually manifests as a proximal endobronchial calcification associated with distal obstructive pneumonia.
OBJECTIVE: The purpose of this study was to describe the radiographic and high-resolution CT (HRCT) findings of adenovirus pneumonia in five patients. CONCLUSION: Adenovirus pneumonia in adults appears as bilateral patchy parenchymal opacities on chest radiographs and as bilateral ground-glass opacities with a random distribution with or without consolidation on HRCT images. These findings, however, are not specific for adenovirus pneumonia.
OBJECTIVE: The purpose of this study was to describe the dynamic CT findings of pulmonary sclerosing hemangioma presenting as a solitary pulmonary nodule and to compare these findings with histopathologic findings. CONCLUSION: On dynamic CT, sclerosing hemangioma has strong and rapid enhancement attributed histopathologically to the presence of hemangiomatous or papillary components in the tumor.
OBJECTIVE: Our objective was to assess the CT findings for endobronchial actinomycosis associated with broncholithiasis. CONCLUSION: Endobronchial actinomycosis associated with broncholithiasis manifests as a proximal obstructive calcified endobronchial nodule associated with distal post-obstructive pneumonia of the involved lobe or segment on CT. The possibility of endobronchial actinomycosis should be entertained when broncholithiasis is seen on CT in tuberculosis-endemic areas.
To determine overall detection rates of lung cancer by low-dose CT (LDCT) screening and to compare histopathologic and imaging differences of detected cancers between high- and low-risk groups, this study included 6,406 asymptomatic Korean adults with >or=45 yr of age who underwent LDCT for lung cancer screening. All were classified into high- (>or=20 pack-year smoking; 3,353) and low-risk (3,053; <20 pack-yr smoking and non-smokers) groups. We compared CT findings of detected cancers and detection rates between high- and low-risk. At initial CT, 35% (2,255 of 6,406) had at least one or more non-calcified nodule. Lung cancer detection rates were 0.36% (23 of 6,406). Twenty-one non-small cell lung cancers appeared as solid (n=14) or ground-glass opacity (GGO) (n=7) nodules. Cancer likelihood was higher in GGO nodules than in solid nodules (p<0.01). Fifteen of 23 cancers occurred in high-risk group and 8 in low-risk group (p=0.215). Therefore, LDCT screening help detect early stage of lung cancer in asymptomatic Korean population with detection rate of 0.36% on a population basis and may be useful for discovering early lung cancer in low-risk group as well as in high-risk group.
Neuroendocrine tumors of the lung arise from Kulchitzky cells of the bronchial mucosa and comprise typical carcinoid, atypical carcinoid, large cell neuroendocrine carcinoma (LCNEC), and small cell lung cancer (SCLC). At histopathologic analysis, these tumors demonstrate a progressive increase in the number of mitotic figures per 10 high-power fields of viable tumor and in the extent of necrosis, with typical carcinoid having the lowest values and SCLC having the highest. Typical carcinoid is less aggressive than atypical carcinoid, although these tumors have similar gross pathologic and radiologic features; LCNEC has a prognosis between that of atypical carcinoid and that of SCLC. SCLC is the most aggressive pulmonary neuroendocrine tumor and has the most specific imaging feature: mediastinal or hilar lymphadenopathy. At CT, carcinoid tumors appear as a spherical or ovoid nodule or mass with a well-defined and slightly lobulated border. When nonspherical, the tumor is elongated with its long axis parallel to adjacent bronchi. Calcification or ossification is seen in up to 30% of cases. The CT findings of LCNEC are nonspecific and are similar to those of other non-small cell lung cancers. Although there are some overlapping features between these tumors, integration of the clinical and imaging features may be helpful in differentiation of pulmonary neuroendocrine tumors.
Pneumoconiosis may be classified as either fibrotic or nonfibrotic, according to the presence or absence of fibrosis. Silicosis, coal worker pneumoconiosis, asbestosis, berylliosis, and talcosis are examples of fibrotic pneumoconiosis. Siderosis, stannosis, and baritosis are nonfibrotic forms of pneumoconiosis that result from inhalation of iron oxide, tin oxide, and barium sulfate particles, respectively. In an individual who has a history of exposure to silica or coal dust, a finding of nodular or reticulonodular lesions at chest radiography or small nodules with a perilymphatic distribution at thin-section computed tomography (CT), with or without eggshell calcifications, is suggestive of silicosis or coal worker pneumoconiosis. Magnetic resonance imaging is helpful for distinguishing between progressive massive fibrosis and lung cancer. CT and histopathologic findings in asbestosis are similar to those in idiopathic pulmonary fibrosis, but the presence of asbestos bodies in histopathologic specimens is specific for the diagnosis of asbestosis. Giant cell interstitial pneumonia due to exposure to hard metals is classified as a fibrotic form of pneumoconiosis and appears on CT images as mixed ground-glass opacities and reticulation. Berylliosis simulates pulmonary sarcoidosis on CT images. CT findings in talcosis include small centrilobular and subpleural nodules or heterogeneous conglomerate masses that contain foci of high attenuation indicating talc deposition. Siderosis is nonfibrotic and is indicated by a CT finding of poorly defined centrilobular nodules or ground-glass opacities.
Integrated fluorine-18 fluorodeoxyglucose positron emission tomography (PET)-computed tomography (CT) for adrenal gland imaging in cancer patients allows early detection and accurate localization of adrenal lesions and differentiation of metastatic nodules from benign lesions, thereby facilitating treatment planning. However, false-positive findings are encountered at integrated PET-CT in approximately 5% of adrenal lesions identified as positive at PET, including adrenal adenomas, adrenal endothelial cysts, and inflammatory and infectious lesions. Moreover, false-negative findings may be seen in adrenal metastatic lesions with hemorrhage or necrosis, small-sized (<10-mm) metastatic nodules, and metastases from pulmonary bronchioloalveolar carcinoma or carcinoid tumors. An awareness of the potential pitfalls of integrated PET-CT enhances the diagnostic efficacy of this modality by allowing differentiation of metastatic adrenal lesions from other abnormalities.