Thoracic Cysts and Mimics: Diagnosis on Imaging

Table 1: Congenital and acquired causes of cavitary lesionsCysts and cavities are commonly seen lesions in the lung. A chest X-ray is the initial investigation, and contrast-enhanced computed tomography imaging can help in confirming the diagnoses.[1–3] Cavities or cysts can be thick-walled or thin-walled. A lung cyst or cystic airspace is described as a parenchymal space with a well-defined, thin wall (usually <2 mm in thickness. The term cavity is used for an air-containing lesion with a relatively thick wall (>2 mm).[1] Cystic or cavitary lesions in children can be classified as congenital or acquired [Table 1]. Declaration of patient consent The authors certify that they have obtained patient consent forms for images and other clinical information to be reported in the journal. The patients understand that their name sand initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.Image 1: Frontal chest radiograph antero-posterior view demonstrates large, lucent multicystic lesion (white arrow) predominantly in the right hemithorax and crossing the midline, causing mass effect with tracheomediastinal shift to the left and compression of adjacent lung parenchyma with blunting of right costophrenic angle (black arrow)Image 2: Computed tomography chest (lung and mediastinal window) Axial and coronal sections-reveals an air filled multicystic lesion with multiple large macrocysts (≈2–10 cm) within the right middle lobe (white arrow), crossing the midline to left side, demonstrating well-defined thin walls and air–fluid levels (white arrow head) in several cystic spaces, indicating superimposed infection. The cysts cause mass effect with partial compression of the adjacent right upper and lower lobes and mediastinal displacement. The constellation of findings is characteristic of infected macrocystic Congenital Pulmonary Airway Malformation (Type I)Image 3: Frontal chest radiograph Posterior–Anterior view shows an ill-defined multi-cystic lesion (White arrow) with small cystic spaces noted in the perihilar region of the right lungImage 4: Computed tomography scan of the thorax [lung window axial, sagittal sections, MinIP (Minimum intensity projection-three dimensional reconstruction) coronal sections] showing multi-cystic lesion (white arrow) comprising of multiple thin-walled, air-filled cystic spaces of variable sizes involving the right upper lobe with largest cyst measuring <2 cm in size (white star) with surrounding consolidation (black asterix), consistent with Congenital Pulmonary Airway Malformation (CPAM), likely with superadded infection. The cysts in the above case measure 0.5-2 cm in diameter, consistent with Type II CPAMImage 5: Frontal chest X-ray anterior-posterior view showing marked overinflation of the left upper lobe (white arrow), demonstrated by increased radiolucency with attenuation of vascular markings. The hyperexpanded lobe causes mass effect in the form of depression and flattening of the left hemidiaphragm (Asterix), and contralateral mediastinal shift with radiolucency extending across midline to the right side (white star). s/o Congenital lobar overinflationImage 6: Computed tomography scan of the thorax [lung window axial, coronal and sagittal sections and MinIP (Minimum intensity projection- three dimensional reconstruction) coronal sections] show the left upper lobe to be markedly hyperlucent and overinflated (white arrow), with attenuated vascular markings, increased lobar volume, with the expanded lobe herniating across the midline in retrosternal region to right side (white star), associated with tracheo-mediastinal shift to contralateral side, confirming the diagnosisImage 7: Frontal chest X-ray shows well-defined, thin-walled, round, air-filled cystic lesions (white arrows) in the mid and lower zones of B/L lungs. Note was made of air in the right pleural cavity (black arrow), showing complete absence of broncho-vascular markings in this region, with underlying collapsed right lung (star). Findings suggestive of large pneumatoceles in both lungs with area of collapse in right lung and right pneumothoraxImage 8: Axial computed tomography scan of the thorax (lung window) showing well defined, thin and smooth walled, air-filled cystic lesions (white star) in B/L lower lobes consistent with pneumatoceles. The adjacent lung parenchyma in left lower lobe shows evidence of consolidation with air bronchograms (black arrow)Image 9: Frontal Chest X-ray anterior-posterior view demonstrating consolidation with cavitatory breakdown (white arrow) in right mid and lower zones and left lower zone. Associated patchy bilateral air-space opacities in the B/L upper zones (black arrow)Image 10: Axial computed tomography chest (lung and mediastinal window)-showing a large thick-walled cavitary lesion (white star) with surrounding consolidation with air bronchograms (black arrow) in the right middle and lower lobe. No significant pleural effusion or pneumothorax is seen, consistent with necrotizing pneumoniaImage 11: A frontal chest X-ray anterior-posterior view shows consolidation in the right middle lobe (white arrow) with ill-defined area of lucency with irregular margins within (Asterix). Corresponding Right lateral X-ray shows consolidation confined to the right middle lobe (white arrow), outlined by the minor and the major fissure, with an ill-defined area of lucency within the consolidation (*)Image 12: Computed tomography chest (lung window) Axial and coronal sections showing consolidation in right middle lobe with underlying bronchiectasis (black arrow) with a thick-walled irregular cavitatory lesion (white arrow) noted in medial segment of right middle lobe with. Appearance suggestive of active chronic pulmonary tuberculosisImage 13: Frontal chest radiograph, posterior–anterior view, demonstrates few cavitatory lesions in the right mid and lower zones (white arrow), along with scattered nodular and reticulonodular opacities in the B/L upper zones, right mid and lower zone of lungImage 14: Computed tomography chest lung window axial sections (MPR and MIP [Maximum Intensity Projection] reconstructions) – show cavitary breakdown in the superior segment of the right lower lobe (black arrow), with adjacent discrete centrilobular nodules and few forming tree-in-bud pattern (curved arrow), along with mild bronchiectasis (white arrowhead): features collectively suggestive of active endobronchial spread of tuberculosis.Image 15: Frontal Chest radiograph anterior-posterior view showing a well-defined, thin walled cavity (black arrow) in right upper zone with smooth and regular margins, predominantly filled with air and shows a rounded soft tissue opacity (black star) in dependent part of cavity with an air crescent sign (air-meniscus). Another similar cavity with nodular opacity in left upper zone (arrow head), with diffuse nodular lesions in remaining parts of B/L lung fields and some asymmetric patchy opacities (curved black arrow) in right lower zone. Findings are consistent with fungal balls (aspergillomas) within pre-existing cavities in bilateral pulmonary apical regions, on a background of chronic infective changes in both lungs.Image 16: Axial High-Resolution Computed Tomography images (mediastinal and lung window) of the thorax showing multiple rounded to irregular fibro-cavitatory lesions (white arrow), showing thin regular smooth walls in the B/L upper lobes containing rounded, soft-tissue density nodular masses (asterix) in the dependent parts, with air crescent (air-meniscus) surrounding them – characteristic of a fungal balls (aspergillomas) within pre-existing cavities. Adjacent parenchymal fibrosis and traction bronchiectasis (Black arrow), and volume loss are also notedImage 17: Chest radiograph - Posterior-Anterior and right lateral views, show a large cavity with thin, regular, smooth walls (white arrow) with well-defined superior and medial walls and a large air fluid level (arrowhead), located in the right mid and lower zones, causing mild mediastinal shift to leftImage 18: Axial, cor and sag computed tomography (lung and mediastinal window) images demonstrate a large, thin-walled cystic lesion (white star) in the right lower lobe with air-fluid level (white arrow) and multiple irregular collapsed membranes floating within cyst cavity (water lily sign) (black arrow) with mildly enhancing wall (white arrow head) and adjacent lung parenchyma shows atelectasis (black asterix). Mild pleural effusion (curved arrow), on right side S/O partially ruptured hydatid cystImage 19: Frontal and lateral chest radiographs showing a lobulated, ill-defined, thick-walled cavitatory lesion (white arrow) with air fluid level in dependent part (white star) of the cavity, located in the left lower lobe and retrocardiac region, overlapping the spine on lateral X-ray, s/o Lung abscess. The surrounding lung parenchyma demonstrates patchy consolidation (black Asterix) in left lower lobeImage 20: Axial and coronal contrast-enhanced computed tomography chest images (lung and mediastinal window) demonstrate a thick-walled cavity (black arrow) with irregular inner wall, in the left lower lobe. The cavity shows air-fluid level (star), and peripheral rim enhancement consistent with Lung abscess. The surrounding lung parenchyma exhibits consolidation. No significant pleural effusion or mediastinal lymphadenopathy is seenImage 21: Frontal chest X-ray posterior-anterior view shows multiple small, thick-walled cystic lucencies (white arrows) in the mid and lower zones of both lungs. Note is made of hyperinflated lung fields, with bilateral flattened hemidiaphragmsImage 22: An adolescent male presented with cough and hemoptysis. Axial and coronal high-resolution computed tomography chest lung window images-show multiple ectatic bronchi (curved white arrows) in both lungs, with peribronchial thickening, and few bronchi showing air fluid levels (white arrow) within, s/o Cystic bronchiectasis with retained secretions/superadded infection. B/L lung fields appear hyperinflated, as evident by the hyperlucency and sparsity of vascular markings, possibility of cystic fibrosis was suggested