Gloved Þnger sign is originally described on chest radiography and represents mucoid impaction of the branching bronchi [1]. The sign is formed by branching tubular, toothpaste, or Þngerlike densities [2]. On CT, the dilated bronchi, Þlled and impacted with mucus (usually ßuid attenuation but variable depending on the constituents of content in the dilated bronchi), generate a gloved Þnger appearance [3] (Fig. 10.1).

Diseases Causing the Sign

Any airway obstructive lesions may result in gloved Þnger sign. Benign and malignant neoplasms (Fig. 10.2) causing airway obstruction can cause distal bronchiectasis and mucoid impaction. Developmental airway disease, bronchial atresia (Fig. 10.1), usually appears as gloved Þnger sign. Broncholithiasis, bronchial tuberculosis and stricture

(Fig. 10.3), intralobar pulmonary sequestration, and foreignbody aspiration may also cause mucoid impaction and gloved Þnger sign. Allergic bronchopulmonary aspergillosis

(ABPA) (Figs. 10.4 and 10.5) and cystic Þbrosis with or without ABPA are the two most common nonobstructive diseases causing gloved Þnger sign on radiologic examinations [2] (Table 10.1).

Distribution

Congenital bronchial atresia involves the parahilar airways [4]. Broncholithiasis is characterized and associated with peribronchial calciÞc nodal disease and thus involves usually the segmental bronchi [5]. Aneurysmal appearance of the medium-sized bronchi is seen on CT scans in bronchial tuberculosis [6]. ABPA characteristically involves central airways. Mucus plugging and bronchiectasis usually involve the airways of the upper and middle lung zones in cystic Þbrosis.

Almost all patients with ABPA have asthma [7]. In approximately two-thirds of patients with bronchial atresia, the lesions are incidentally found. The remaining patients complain of cough, hemoptysis, fever, and shortness of breath [8]. Hemoptysis is a usual sign in broncholithiasis; it may be massive. Other parenchymal tuberculous lesions usually accompany gloved Þnger sign in bronchial tuberculosis. Cystic Þbrosis is a disease of children, adolescence, and young adults, and most signs and symptoms affect the respiratory or the digestive system.

Key Points for Differential Diagnosis

1.Bronchiectasis with mucoid impaction is common in ABPA but occurs only occasionally in asthmatic patients with a positive skin test to A. fumigatus but without other features of the disease [9].

2.Gloved Þnger sign and bronchial obstruction are usually accompanied by mosaic perfusion area (hyperlucent lung) of the surrounding lung parenchyma [4].

3.CT helps localize correctly the endobronchial or peribronchial location of calciÞed lymph nodes in broncholithiasis [5].

4.Other parenchymal tuberculous lesions usually accompany gloved Þnger sign in bronchial tuberculosis [6].

Bronchial Atresia

Pathology and Pathogenesis

Atresia of a segmental or subsegmental bronchus classically results in a central mucus-Þlled cyst (mucocele) at the distal point of atresia, dilated distal airways with mucus, and

Fig. 10.1 Bronchial atresia showing gloved Þnger appearance in a 43-year-old woman. (a) Mediastinal window image of enhanced CT scan (5.0-mm section thickness) obtained at level of the suprahepatic inferior vena cava shows V-shaped low-attenuation lesion (arrows) in the right lower lobe. (b) Lung window image of CT scan obtained at

similar level to (a) demonstrates same branching lesion. Please note low-attenuation area (arrows) surrounding branching lesion. (c) CT scan obtained at level of liver dome displays branching nodular lesions (arrows) in the right lower lobe

hyperinßated microcystic distal parenchyma. Abundant inspissated mucus is typically noted within proximal airway lumens immediately distal to the focus of atresia and adjacent airspaces. Mucus-Þlled bronchus is continuous with the distal airways but has no connection with the more proximal airways. Infection may result in inßammation and Þbrosis. The distal hyperinßation is due to collateral ventilation and air trapping [10].

Symptoms and Signs

The left upper lobe is most commonly involved (two-thirds of patients), particularly the apicoposterior segmental bronchus. Most patients with bronchial atresia are asymptomatic, but dyspnea, chest pain, recurrent pneumonia up to 20 % of patients, pneumothorax, hemoptysis, and asthma have been reported [11].

Fig. 10.2 Gloved Þnger sign associated with mucus retention in airways distal to endobronchial metastasis in a 54-year-old man with renal cell carcinoma. (a, b) Lung window images of CT scans (5.0-mm section thickness) obtained at levels of the azygos arch (a) and main bronchi (b), respectively, show branching tubular lesions (arrows) in posterior segment of the right upper lobe, representing mucus plugging. Also note endobronchial tumor (arrowhead) in the posterior segmental bronchus of the right upper lobe. Bronchoscopic biopsy disclosed endobronchial metastatic renal cell carcinoma nodule (not shown here).

Small centrilobular nodules and branching nodular structures in anterior segment of the right upper lobe are due to concurrent nontuberculous mycobacterial pulmonary disease. (c) High-magniÞcation photomicrograph (×200) of pathologic specimen obtained from the right upper lobe with right upper lobectomy (from a different patient but with same disease) displays endobronchial tumor nodules (arrows). (d) High-magniÞcation photomicrograph (×100) discloses endobronchial tumor nodules (arrows) and distal mucus plugging (open arrows) within the dilated bronchi

CT Findings

Characteristic CT Þndings of bronchial atresia include bronchial occlusion, mucoid impaction with bronchial dilatation (bronchocele) immediately distal to the atretic bronchus, and

decreased vascularity and attenuation and increased volume of the affected segment [12, 13] (Fig. 10.1). It most commonly affects the apicoposterior segmental bronchus of the left upper lobe, followed by segmental bronchi of the right upper lobe, the right middle lobe, and rarely the right lower lobe [14].

Fig. 10.3 Gloved Þnger sign associated with tuberculous bronchial stricture involving the left lower lobar bronchus in a 67-year-old man who had a history of previous tuberculous infection. (a, b) Mediastinal window and coronal reformatted images (2.0-mm section thickness) of enhanced CT scans obtained at levels of the descending thoracic aorta

show branching tubular lesions (arrows) in the left lower lobe, representing mucus plugging. Also note the hypertrophied left bronchial artery and its branches (arrowheads) and destroyed left upper lobe owing to tuberculous infection

Fig. 10.4 Allergic bronchopulmonary aspergillosis in a 64-year-old asthmatic man. (a, b) Lung window images of consecutive CT scans (2.5-mm section thickness) obtained at levels of liver dome show mucus

plugging (arrows) in the dilated bronchi in both lower lobes. Also note the dilated bronchi (bronchiectasis) without mucus Þlling