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Reversed Halo Sign in Pulmonary Paracoccidioidomycosis
Abstract and Figures
The purpose of this study was to evaluate the prevalence of the reversed halo sign in pulmonary paracoccidioidomycosis.
The high-resolution CT scans (1- or 2-mm collimation scans) of 148 consecutive patients with proven pulmonary paracoccidioidomycosis were reviewed to determine the prevalence of the reversed halo sign in these patients. The reversed halo sign was defined as central ground-glass opacity surrounded by a crescent or ring of consolidation. The images were reviewed by two radiologists who reached a decision by consensus.
A reversed halo sign was found in 15 patients (10%), including 13 men and two women ranging in age from 20 to 58 years (mean, 48 years). Three patients had only one reversed halo sign, one had two lesions, and the remaining had multiple lesions. The size of the sign ranged from 10 to 50 mm (average, 20 mm). In two cases the reversed halo sign was the only finding on CT. The most common associated findings seen in the remaining 13 patients included bilateral patchy areas of ground-glass attenuation (n = 10), parenchymal bands (n = 8), and small centrilobular nodules (n = 8). Three patients underwent surgical lung biopsy. Histologically the central area of the lesions consisted of an inflammatory infiltrate in the alveolar septa, composed of macrophages, lymphocytes, plasma cells, and some giant cells, with relative preservation of the alveolar spaces. The periphery of the lesion consisted of dense and homogeneous intraalveolar cellular infiltrate. There was no evidence of organizing pneumonia.
The reversed halo sign is seen in approximately 10% of patients with paracoccidioidomycosis. In these patients, this sign reflects the presence of a central area of predominantly interstitial inflammation surrounded by predominantly air-space infiltration.
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... Later on, it was also observed among some immunocompetent patients with infectious pneumonia, such as tuberculosis or other bacterial and fungal infections [9][10][11]. It was also reported in several inflammatory conditions like sarcoidosis, pulmonary neoplasms, and after radiotherapy [ 12 ]. ...
The reversed halo sign (RHS) is a specific radiological image observed mostly on computed tomography (CT) scans as a focal round area of ground-glass attenuation surrounded by a crescent or ring of consolidation. It is common to many entities of respiratory diseases and can be found in both infectious, noninfectious inflammatory pathologies and some malignant tumors, including invasive pulmonary fungal infection, tuberculosis (TB), community-acquired pneumonia, granulomatosis, sarcoidosis. It is also seen in pulmonary neoplasms and infarction, and following radiation and radiofrequency.
We report the case of an immunocompetent 54-year-old North African male patient, initially hospitalized for chronic cough associated with dysphonia and general symptoms such as weight loss, fever, and night sweats. Radiological exploration surprisingly confirmed the presence of RHS, tuberculosis was confirmed by a postbronchoscopy positive sputum Xpert MTB/RIF essay tuberculosis after we started antibacillary treatment, and the evolution was spectacular with regression of the lesions.
The objective of this report is to increase knowledge about RHS and its pathological correlation with TB. Since it is not specific to any disorder, it is important to explore its finding in a clinical and epidemiological manner, especially in endemic countries where the prevalence of tuberculosis is still high.
... "Galaxy sign", "rosette sign", and "reversed halo sign" have also been proposed as CT manifestations of APTB 8-13 . Unfortunately, these imaging signs did not cover a variety of imaging appearances of bronchogenic spread of APTB and could overlap with many diseases, such as cryptogenic organizing pneumonia (COP), sarcoidosis, pulmonary lymphomatoid granulomatosis, invasive pulmonary fungal infections [14][15][16][17] and so forth. Thus, the aim of this study was to propose a new CT feature " reworks sign" to comprehensively describe the bronchogenic spread of APTB and may be more conducive to identify APTB on CT. ...
Background: Imaging manifestations of active pulmonary tuberculosis (APTB) on CT described in previous studies did not cover a variety of imaging appearances of bronchogenic spread of pulmonary tuberculosis (PTB) and could overlap with many other diseases.
Purpose: To propose a CT imaging sign-“fireworks sign” to demonstrate the bronchogenic spread of active pulmonary tuberculosis and correlate with histopathology.
Methods: A total of 679 patients with confirmed PTB were enrolled in this study. The histological proof of APTB was obtained by means of sputum smear in 429 patients, bronchoalveolar lavage in 167 patients, biopsy or surgical histopathology in 83 patients. The clinical and imaging data were retrospectively reviewed. The “fireworks sign” on CT which was a focal conglomeration (clusters) of multiple nodules could be classified into three patterns: pistil pattern (consolidation or more nodules in the central region and fewer nodules in the peripheral region), dandelion pattern (fewer nodules in the central region and more nodules in the peripheral region) and peony pattern (nodules evenly distributed in the affected region). Imaging assessment included the pattern, number, site of fireworks sign and other associated imaging features. The histopathological comparison of fireworks sign was also performed in the biopsy or surgical specimens.
Results: A total of 180 lesions with fireworks sign were found in 106 patients (106/679, 15.6%), including 71 pistil patterns, 21 dandelion patterns and 88 peony patterns, respectively. More than two patterns of fireworks sign presented in 68 patients. Histopathological proof was achieved in 83 patients and the fireworks sign was composed of centrilobular nodules which corresponded pathologically to caseous necrotic granulomas in bronchioles and alveolar ducts. Single lobe, multiple lobes of unilateral lung, and bilateral lungs involvement was presented in 66.0% (70/106), 6.6% (7/106), and 27.4% of patients (29/106), respectively. The fireworks sign decreased in density or turned into ground-glass opacity during or after anti-tuberculosis treatment in 34 patients in a series of follow-up CT scans. Other imaging features including tree-in-bud sign (21.7%), consolidation (18%), cavity (24%), bronchiectasis (21.7%), pleural effusion (2.8%), pneumothorax (1.9%), pleural thickening (35.9%) and mediastinal lymph node enlargement (13.2%) were also found.
Conclusion: The fireworks sign is a CT feature of bronchogenic dissemination of active pulmonary tuberculosis and histopathologically corresponds to a comglomeration of caseous necrotic granulomas in the bronchiole and alveolar ducts.
The reversed halo sign was initially reported as a representative computed tomography scan finding of cryptogenic organizing pneumonia. Since then, however, it has been reported in various diseases and is now considered a nonspecific finding. However, there are no cases of humidifier lung with the reversed halo sign. An 82-year-old Japanese male patient presented with moving difficulties 48 days after starting darolutamide treatment for prostate cancer. He was admitted to the hospital due to acute pneumonia, which presented as bilateral extensive nonsegmental ground-glass opacities in the peripheral regions and extensive areas of ground-glass opacity with a circumferential halo of consolidation, with the reversed halo sign on computed tomography scan. After darolutamide discontinuation with the concomitant administration of antibiotics, the patient's pneumonia improved, and he was discharged from the hospital. However, within a few days, he was again admitted to the hospital due to pneumonia. He was found to have been using an ultrasonic humidifier at home and was then diagnosed with humidifier lung based on the bronchoscopy and provocative testing findings. Hence, ultrasonic humidifier lung should be considered as a differential diagnosis in patients presenting with the reversed halo sign, and a detailed medical history must be taken.
The reversed halo sign, which was named originally from the disease cryptogenic organizing pneumonia, refers to a focal, rounded area of ground-glass opacity surrounded by a more or less complete ring of consolidation.
Background/aim:
Available information on the radiological findings of the 2019 novel coronavirus disease (COVID-19) is constantly updated. Ground glass opacities (GGOs) and consolidation with bilateral and peripheral distribution have been reported as the most common CT findings, but less typical features can also be identified. According to the reported studies, SARS-CoV-2 infection is not limited to the respiratory system, and it can also affect other organs. Renal dysfunction, gastrointestinal complications, liver dysfunction, cardiac manifestations, and neurological abnormalities are among the reported extrapulmonary features. This review aims to provide updated information for radiologists and all clinicians to better understand the radiological manifestations of COVID-19.
Materials and methods:
Radiological findings observed in SARS-CoV-2 virus infections were explored in detail in PubMed and Google Scholar databases.
Results:
The typical pulmonary manifestations of COVID-19 pneumonia were determined as GGOs and accompanying consolidations that primarily involve the periphery of the bilateral lower lobes. The most common extrapulmonary findings were increased resistance to flow in the kidneys, thickening of vascular walls, fatty liver, pancreas, and heart inflammation findings. However, these findings were not specific and significantly overlapped those caused by other viral diseases, and therefore alternative diagnoses should be considered in patients with negative diagnostic tests.
Conclusion:
Radiological imaging plays a supportive role in the care of patients with COVID-19. Both clinicians and radiologists need to know associated pulmonary and extrapulmonary findings and imaging features to help diagnose and manage the possible complications of the disease at an early stage. They should also be familiar with CT findings in patients with COVID-19 since the disease can be incidentally detected during imaging performed with other indications.
The reversed halo sign is characterised by a central ground-glass opacity surrounded by denser air-space consolidation in the shape of a crescent or a ring. It was first described on high-resolution CT as being specific for cryptogenic organising pneumonia. Since then, the reversed halo sign has been reported in association with a wide range of pulmonary diseases, including invasive pulmonary fungal infections, paracoccidioidomycosis, pneumocystis pneumonia, tuberculosis, community-acquired pneumonia, lymphomatoid granulomatosis, Wegener granulomatosis, lipoid pneumonia and sarcoidosis. It is also seen in pulmonary neoplasms and infarction, and following radiation therapy and radiofrequency ablation of pulmonary malignancies. In this article, we present the spectrum of neoplastic and non-neoplastic diseases that may show the reversed halo sign and offer helpful clues for assisting in the differential diagnosis. By integrating the patient's clinical history with the presence of the reversed halo sign and other accompanying radiological findings, the radiologist should be able to narrow the differential diagnosis substantially, and may be able to provide a presumptive final diagnosis, which may obviate the need for biopsy in selected cases, especially in the immunosuppressed population.
Paracoccidioidomycosis (PCM) is the most common systemic mycosis in Latin America. Although most cases occur in developing countries, recent immigration patterns and an increase in travel have led to a growing number of PCM cases in the United States and Europe. PCM is caused by the dimorphic fungus Paracoccidioides brasiliensis, and the chronic form may progress to severe pulmonary involvement. Several radiologic patterns have been described for pulmonary PCM, including linear and reticular opacities, variable-sized nodules, patchy ill-defined opacities, airspace consolidation, and cavitary lesions. Fibrosis and paracicatricial emphysema are common associated findings. Chest computed tomography (CT) is the method of choice for evaluating pulmonary PCM, with the most common CT findings being ground-glass attenuation, consolidation, small or large nodules, masses, cavitations, interlobular septal thickening, emphysema, and fibrotic lesions. PCM is also an important cause of the "reversed halo" sign at high-resolution CT and should be considered in the differential diagnosis. Awareness of the multiple radiologic manifestations of PCM as well as its epidemiologic and clinical characteristics may permit early diagnosis and initiation of specific treatment, thereby reducing associated morbidity and mortality.
Objective:
The purposes of this article are to describe common and uncommon imaging signs and patterns of pulmonary infections and to discuss their underlying anatomic and pathophysiologic basis.
Conclusion:
Imaging plays an integral role in the diagnosis and management of suspected pulmonary infections and may reveal useful signs on chest radiographs and CT scans. Detected early, these signs can often be used to predict the causative agent and pathophysiologic mechanism and possibly to optimize patient care.
A 56-year-old woman, non-smoker, who complained of dry cough and dyspnea during the last month came to the emergency department due to increased dyspnea. The chest X-ray showed areas of poorly defined, bilateral alveolar opacities, leading to the diagnosis of bronchopneumonia with partial respiratory failure. During admission, she experienced an exacerbation of the dyspnea. A high-resolution computed tomography scan was performed, showing areas of ground glass opacities with interlobular septal thickening («crazy-paving» pattern), predominantly in lower lobes. She required mechanical ventilation and she was admitted to the intensive care unit. Subsequently, an open lung biopsy was performed. The following questions should be proposed:
–Is it possible to make the diagnosis of Organizing Pneumonia (OP) only by clinical findings?–Are the imaging test findings pathognomonic?–Is a lung biopsy required to confirm the diagnosis of OP?–Is it necessary to wait for histologic confirmation to start treatment when OP is suspected?
A 56-year-old woman, non-smoker, who complained of dry cough and dyspnea during the last month came to the emergency department due to increased dyspnea. The chest X-ray showed areas of poorly defined, bilateral alveolar opacities, leading to the diagnosis of bronchopneumonia with partial respiratory failure. During admission, she experienced an exacerbation of the dyspnea. A high-resolution computed tomography scan was performed, showing areas of ground glass opacities with interlobular septal thickening («crazy-paving» pattern), predominantly in lower lobes. She required mechanical ventilation and she was admitted to the intensive care unit. Subsequently, an open lung biopsy was performed. The following questions should be proposed:
A variety of fungal pulmonary infections can produce radiologic findings that mimic lung cancers. Distinguishing these infectious lesions from lung cancer remains challenging for radiologists and clinicians. In such cases, radiographic findings and clinical manifestations can be highly suggestive of lung cancer, and misdiagnosis can significantly delay the initiation of appropriate treatment. Likewise, the findings of imaging studies cannot replace the detection of a species as the aetiological agent. A biopsy is usually required to diagnose the infectious nature of the lesions. In this article, we review the clinical, histologic and radiologic features of the most common fungal infections that can mimic primary lung cancers, including paracoccidioidomycosis, histoplasmosis, cryptococcosis, coccidioidomycosis, aspergillosis, mucormycosis and blastomycosis.
Introduction
Diagnostic guidelines recommend a lung biopsy to make the diagnosis of cryptogenic organizing pneumonia (COP). However, in some cases, in the presence of a typical clinical picture, the diagnosis can be made without histological proof: the combination of a “reversed halo sign” and migratory areas of patchy alveolar consolidation on the CT-scan is strongly suggestive. Steroids are the recommended treatment, but relapses and complications of steroids occur frequently whereas the morbidity of COP is usually low and the evolution is often the same with or without treatment.
Case report
We report the case of a 51 year old woman with mild COP. The diagnosis was made according to the clinico-radiological criteria that we propose, without any formal histological proof. Treatment consisted of a short course of steroids, which led to spectacular clinical and radiological improvement but was withdrawn due to poor tolerance. The patient refused further treatment but clinical progress was favourable. After a follow-up period of 2.5 years a CT-scan showed evidence of a radiological relapse but the patient remained asymptomatic.
Conclusion
In this article, we do not attempt to prove that lung biopsy and steroid treatment are unnecessary in the management of COP, but we would like to propose that, in some situations with the coexistence of a “reversed halo sign” and migratory areas of patchy consolidation on the CT-scan, in the context of a typical clinical presentation and mild symptoms, the usefulness of lung biopsy and steroid treatment is debatable.
Computed tomography (CT) is considered to be the gold standard method for the assessment of morphological changes in the pulmonary parenchyma. Although its spatial resolution is lower than that of CT, MRI offers the advantage of characterizing different aspects of tissue based on the degree of contrast on T1-weighted image (WI) and T2-WI. In this article, we describe and correlate the MRI and CT features of several common patterns of parenchymal lung disease (air trapping, atelectasis, bronchiectasis, cavitation, consolidation, emphysema, ground-glass opacities, halo sign, interlobular septal thickening, masses, mycetoma, nodules, progressive massive fibrosis, reverse halo sign and tree-in-bud pattern). MRI may be an alternative modality for the collection of morphological and functional information useful for the management of parenchymal lung disease, which would help reduce the number of chest CT scans and radiation exposure required in patients with a variety of conditions.
Paracoccidioidomycosis is a deep mycosis endemic to Latin America, with considerable morbidity and mortality. It is caused by the dimorphic fungus Paracoccidioides brasiliensis, which affects, among other organs in the human body, the oral cavity. Fungus virulence and immunocompetence of the host determine the establishment of infection or active disease, whose severity and clinical behaviour depend mostly on the cellular immune response of the host. Often, oral lesions constitute the first sign and site of confirmation of diagnosis, which in most cases is delayed. The success of the treatment depends on early and correct diagnosis, as well as on the patient's adherence to the drug therapy.