Infected tracheal diverticulum mimicking an aggressive mediastinal lesion on FDG PET/CT: an interesting case with review of the literature

The differential diagnosis for intense hypermetabolic mediastinal lesions on positron emission tomography (PET) could benefit from the combined morphological and metabolic information present in a fluorodeoxyglucose (FDG) PET/CT study. We report a case of an infected tracheal diverticulum mimicking an FDG-avid malignancy in a patient with a history of chronic lymphoproliferative disease. We review the literature for a systematic approach in the differential diagnosis of cystic mediastinal lesions. The embryological development of the normal tracheobronchial tree is reviewed, followed by a presentation of various congenital and acquired mediastinal lesions. The characteristic CT findings are described for each lesion and the avidity for FDG on PET is mentioned when references are available. This case emphasises that complicated benign processes should be considered in the differential diagnosis of an FDG-avid mediastinal lesion, even in subgroups of patients with significant risk factors for malignancy.

Pulmonary hyalinizing granuloma

OBJECTIVE

To present clinical and pathologic features of pulmonary hyalnizing granuloma through analyzing three cases found in our institution and reviewing cases reported in the English language literature.

METHODS AND RESULTS

Three cases of pulmonary hyalnizing granuloma identified at our institution during the past ten years were reviewed. In the first case, the patient presented with concurrent pulmonary hyalinizing granuloma and histoplasmosis. In the second case, the patient presented with a 5.5 cm lung mass and a separate smaller lesion radiologically resembling bronchogenic carcinoma. There was very prominent polyclonal lymphocytic proliferation at the periphery especially of the smaller lesion likely representing an early stage of the disease process. In the third case, the patient presented with multiple subpleural plaque-like lesions in addition to nodular lesions of the lung. All cases also demonstrated various degrees of lymphocytic infiltration within the lesions. The English literature has been reviewed through searching the PubMed.

CONCLUSION

Since patients with pulmonary hyalinizing granuloma demonstrated a spectrum of clinical presentations, radiologic changes and histologic features with a variety of associated clinical disorders, pulmonary hyalnizing granuloma is more in keeping with a clinicopathologic entity rather than a specific pathologic disease.

Computed tomographic pulmonary angiography vs ventilation-perfusion lung scanning in patients with suspected pulmonary embolism: a randomized controlled trial

CONTEXT

Ventilation-perfusion (V(dot)Q(dot) lung scanning and computed tomographic pulmonary angiography (CTPA) are widely used imaging procedures for the evaluation of patients with suspected pulmonary embolism. Ventilation-perfusion scanning has been largely replaced by CTPA in many centers despite limited comparative formal evaluations and concerns about CTPA's low sensitivity (ie, chance of missing clinically important pulmonary embuli).

OBJECTIVES

To determine whether CTPA may be relied upon as a safe alternative to V(dot)Q(dot scanning as the initial pulmonary imaging procedure for excluding the diagnosis of pulmonary embolism in acutely symptomatic patients.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, single-blinded noninferiority clinical trial performed at 4 Canadian and 1 US tertiary care centers between May 2001 and April 2005 and involving 1417 patients considered likely to have acute pulmonary embolism based on a Wells clinical model score of 4.5 or greater or a positive D-dimer assay result.

INTERVENTION

Patients were randomized to undergo either V(dot)Q(dot scanning or CTPA. Patients in whom pulmonary embolism was considered excluded did not receive antithrombotic therapy and were followed up for a 3-month period.

MAIN OUTCOME MEASURE

The primary outcome was the subsequent development of symptomatic pulmonary embolism or proximal deep vein thrombosis in patients in whom pulmonary embolism had initially been excluded.

RESULTS

Seven hundred one patients were randomized to CTPA and 716 to V(dot)Q(dot scanning. Of these, 133 patients (19.2%) in the CTPA group vs 101 (14.2%) in the V(dot)Q(dot scan group were diagnosed as having pulmonary embolism in the initial evaluation period (difference, 5.0%; 95% confidence interval [CI], 1.1% to 8.9%) and were treated with anticoagulant therapy. Of those in whom pulmonary embolism was considered excluded, 2 of 561 patients (0.4%) randomized to CTPA vs 6 of 611 patients (1.0%) undergoing V(dot)Q(dot scanning developed venous thromboembolism in follow-up (difference, -0.6%; 95% CI, -1.6% to 0.3%) including one patient with fatal pulmonary embolism in the V(dot)Q(dot group.

CONCLUSIONS

In this study, CTPA was not inferior to V(dot)Q(dot scanning in ruling out pulmonary embolism. However, significantly more patients were diagnosed with pulmonary embolism using the CTPA approach. Further research is required to determine whether all pulmonary emboli detected by CTPA should be managed with anticoagulant therapy.

TRIAL REGISTRATION

isrctn.org Identifier: ISRCTN65486961.

Suppurative mediastinitis secondary to Burkholderia cepacia in a patient with cystic fibrosis

Burkholderia cepacia is an important opportunistic pathogen among patients with cystic fibrosis (CF); it is associated with deterioration of lung function, poor outcome following lung transplantation and increased mortality. Fever, an elevated white blood cell count, weight loss and an often fatal deterioration in pulmonary function characterize a particular clinical course, termed "Cepacia syndrome". The present case report describes a 40-year-old man with CF who developed Cepacia syndrome complicated by suppurative mediastinitis, from which B cepacia was isolated. Despite optimal medical and surgical therapy, this patient succumbed to his illness. Those caring for patients with CF should be aware of this potentially catastrophic complication of B cepacia infection, especially in the setting of Cepacia syndrome.

Use of spiral computed tomography contrast angiography and ultrasonography to exclude the diagnosis of pulmonary embolism in the emergency department

Spiral computed tomography (CT) contrast angiography is a promising imaging modality for the diagnosis of pulmonary embolism but the negative predictive value of this test remains controversial. We performed a multi-center prospective cohort study to determine the safety of relying on a negative spiral CT contrast angiography scan to exclude pulmonary embolism. Patients presenting to the Emergency Departments of three tertiary care institutions with clinically suspected pulmonary embolism were potentially eligible for the study. Patients underwent a clinical evaluation to categorize pretest probability into low, moderate, and high categories, and had D-dimer testing performed. Patients at low pretest probability with normal D-dimer were considered to have pulmonary embolism excluded. The remaining patients underwent spiral CT contrast angiography scan of the pulmonary arterial circulation and bilateral venous ultrasound of the proximal leg veins. Patients who were confirmed to have pulmonary embolism or deep vein thrombosis were treated with anticoagulant therapy. Patients in whom the diagnosis of pulmonary embolism was excluded did not receive anticoagulant therapy and were followed for a 3-month period for the development of venous thromboembolic complications. Eight hundred fifty-eight (858) patients were enrolled in this study. Three-hundred sixty-nine (369) patients had low pretest probability and negative D-dimer results and no further diagnostic tests were performed. None of these patients subsequently developed venous thromboembolic complications (0%, 95% confidence interval [CI] 0% to 1.0%). The remaining 489 were referred for spiral CT contrast angiography scan and ultrasound. Sixty-seven patients were confirmed to have pulmonary embolism and an additional 15 patients with negative CT scans had proximal deep vein thrombosis (DVT) on ultrasound for a total prevalence of venous thromboembolism of 82/489 (16.8%). Two of 409 patients who had pulmonary embolism excluded in the initial evaluation phase developed proximal venous thromboembolism (0.5%; 95% CI 0% to 1.8%) in the 3-month follow-up period. These findings suggest that the combination of a negative spiral CT contrast angiography scan and normal venous ultrasound imaging safely excludes the diagnosis of pulmonary embolism in the Emergency Department setting.

Atypical presentation of lymphomatoid granulomatosis in a patient with longstanding sarcoidosis

A patient was recently evaluated who had longstanding sarcoidosis with lymphadenopathy and multiple, small lung nodules, and who developed a new, 9 cm solitary pulmonary mass in the right lower lobe. After thoracotomy, this lesion was ultimately found to be lymphomatoid granulomatosis, a rare lymphoproliferative disorder. Radiographic evaluations of patients with this disorder characteristically show multiple, bilateral reticulonodular opacities that follow the bronchovascular bundles; however, presentation with a solitary, large pulmonary mass is rare. The present case illustrates the need for complete evaluation of new clinical and radiographic findings in the setting of chronic lung disease.

Video-Assisted Thoracoscopic Lung Biopsy as a Possible Cause of Acute Interstitial Pneumonia in a Patient with Nonspecific Interstitial Pneumonia

The present case report describes a 44-year-old woman who presented with dyspnea due to diffuse interstitial lung disease. High-resolution computed tomography showed features of usual interstitial pneumonia, but the lung biopsy obtained by video-assisted thoracoscopy was consistent with a histological pattern of nonspecific interstitial pneumonia. Following the procedure, the patient developed progressive respiratory distress and died on postoperative day 13 with a clinical picture of acute interstitial pneumonia. The autopsy showed evidence of diffuse alveolar damage superimposed on the background pattern of nonspecific interstitial pneumonia. The present case report supports the notion that patients with a variety of subtypes of idiopathic interstitial pneumonias may be at risk of exacerbation of their underlying disease following thoracic procedures, including video-assisted thoracoscopic lung biopsy.

Scintigraphic and MR perfusion imaging in preoperative evaluation for lung volume reduction surgery: pilot study results

PURPOSE

To compare MR perfusion imaging with perfusion scintigraphy in the evaluation of patients with pulmonary emphysema being considered for lung volume reduction surgery.

PATIENTS AND METHODS

Six patients with pulmonary emphysema and two normal individuals were evaluated by MR perfusion imaging, perfusion scintigraphy, and selective bilateral pulmonary angiography. MR images were obtained with an enhanced fast gradient recalled echo with three-dimensional Fourier transformation technique (efgre 3D) (6.3/1.3; flip angle, 30 degrees; field of view, 45-48 cm; matrix, 256 x 160). The presence or absence of perfusion defects in each segment was evaluated by two independent observers.

RESULTS

Using angiography as the gold standard, the sensitivity, specificity, and accuracy of MR perfusion imaging in detecting focal perfusion abnormalities were 90%, 87%, and 89%, respectively, while those of perfusion scintigraphy were 71%, 76%, and 71%, respectively. The diagnostic accuracy of MR perfusion imaging was significantly higher than that of scintigraphy (p<0.001, McNemar test). There was good agreement between two observers for MR perfusion imaging (kappa statistic, 0.66) and only moderate agreement for perfusion scintigraphy (kappa statistic, 0.51).

CONCLUSION

MR perfusion imaging is superior to perfusion scintigraphy in the evaluation of pulmonary parenchymal perfusion in patients with pulmonary emphysema.

Bronchiectasis: accuracy of high-resolution CT in the differentiation of specific diseases

OBJECTIVE

The aim of the study was to determine whether various causes of bronchiectasis can be differentiated by the pattern and distribution of abnormalities seen on high-resolution CT.

MATERIALS AND METHODS

The retrospective study included 82 consecutive patients who had a specific diagnosis of bronchiectasis proven by appropriate clinical and laboratory criteria. All patients underwent high-resolution CT scanning (1- to 1.5-mm collimation). The CT scans were assessed for the presence, extent, type, and anatomic distribution of bronchiectasis by two independent observers who were not aware of the clinical data. The observers recorded their most likely diagnosis and the degree of confidence in that diagnosis.

RESULTS

The two independent observers made a correct diagnosis in 61% of cases (100/164 interpretations). On average, a correct diagnosis was made in 19 (68%) of 28 cases of cystic fibrosis, 16 (67%) of 24 cases of previous tuberculosis, six (43%) of 14 cases of previous childhood infection, five (56%) of nine cases of allergic bronchopulmonary aspergillosis, and four (57%) of seven cases of other causes of bronchiectasis. We found moderate agreement between the observers for the correct diagnosis (kappa = .53) and good agreement for the presence or absence of bronchiectasis in each lobe (kappa = .71).

CONCLUSION

The pattern and distribution of abnormalities revealed by high-resolution CT in patients with bronchiectasis are influenced by the underlying cause. Bilateral, predominantly upper lobe, bronchiectasis is seen most commonly in patients with cystic fibrosis and allergic bronchopulmonary aspergillosis, unilateral upper lobe predominance in patients with tuberculosis, and lower lobe predominance in patients after childhood viral infection.

Idiopathic interstitial pneumonias: diagnostic accuracy of thin-section CT in 129 patients

PURPOSE

To determine whether idiopathic interstitial pneumonias can be differentiated on the basis of the pattern and distribution of abnormalities at thin-section computed tomography (CT).

MATERIALS AND METHODS

Thin-section CT scans in 129 patients with histologically proved idiopathic interstitial pneumonia (35 with usual interstitial pneumonia [UIP], 24 with bronchiolitis obliterans organizing pneumonia [BOOP], 23 with desquamative interstitial pneumonia [DIP], 20 with acute interstitial pneumonia [AIP], and 27 with nonspecific interstitial pneumonia and fibrosis [NIPF]) were independently assessed by two observers without knowledge of clinical or histologic data. The observers recorded the abnormalities, diagnosis, and degree of confidence in their diagnosis. Differential diagnosis was limited to the five types of idiopathic interstitial pneumonia.

RESULTS

The two observers made a correct diagnosis, on average, in 74 (57%) cases. On average, the correct diagnosis was made in 25 (71%) cases of UIP, 19 (79%) of BOOP, 14.5 (63%) of DIP, 13 (65%) of AIP, and 2.5 (9%) of NIPF. The two observers made a correct diagnosis with a high degree of confidence in 50 (39%) readings. There was moderate agreement between the observers for the correct diagnosis (k = 0.55) and for the correct diagnosis with a high degree of confidence (k = 0.65).

CONCLUSION

Except for NIPF, the various subtypes of idiopathic interstitial pneumonias often have a characteristic appearance that allows differentiation at thin-section CT.

Primary pulmonary Hodgkin's disease: CT findings in three patients

The computed tomography (CT) findings in three patients with primary pulmonary Hodgkin's disease are reported. Two patients had unilateral upper lobe cavitated masses and one patient had bilateral lower lobe nodules.