Intrapulmonary Bronchogenic Cyst

Symptoms and Signs

In adults, CCAM may be an incidental Þnding or may be accompanied by symptoms related to recurrent respiratory infections. Less common complications include pneumothorax and the development of carcinoma [54].

CT Findings

The characteristic CT Þndings of CCAM typically consist of a unilocular or multiloculated cyst or a complex soft tissue and cystic mass ranging from 4 to 12 cm in diameter [55]. They are usually located in the lower lobes. Type I lesions have at least one cyst greater than 2 cm in diameter, and type II lesions area characterized by multiple thin-walled cysts ranging from 2 to 20 mm in diameter (Fig. 12.12).

CT-Pathology Comparisons

On CT-pathology correlation, areas of consolidation correspond histologically to areas of glandular or bronchiolar structures with or without areas of endogenous lipid or organizing pneumonia or mucus plugs. Low attenuation areas at CT correspond to areas of air-Þlled microcysts blended with normal lung parenchyma [56].

Patient Prognosis

Because the majority of cases are associated with recurrent infection and risk for the development of carcinoma, the treatment of choice is surgical resection.

Intrapulmonary Bronchogenic Cyst

Pathology and Pathogenesis

Bronchogenic cyst results from abnormal separation of localized portions of the tracheobronchial tree from the adjacent airways between the 3rd and 24th weeks of gestation [53].

Symptoms and Signs

The majority of bronchogenic cysts is asymptomatic and found incidentally on a chest radiograph or CT.

CT Findings

tic mass with a thin smooth wall. In about half of cases, the cyst shows homogeneous attenuation at water density, whereas the attenuation of the others is higher than water density [58]. Occasionally, bronchogenic cysts are air Þlled and multilocular. The lung adjacent to bronchogenic cysts shows areas of mosaic low attenuation and band-like linear attenuation [59] (Fig. 12.14).

CT-Pathology Comparisons

Pathologically, bronchogenic cysts are thin-walled, unilocular, and spherical in shape. They are Þlled with either mucoid or serous ßuid. Therefore, they appear as a homogeneous cystic mass with water attenuation. In about half of cases, the cysts have a higher attenuation, which results from the presence of protein or, less commonly, hemorrhage or calcium oxalate within the mucoid cyst [58]. Areas of mosaic attenuation and band-like linear attenuation adjacent to bronchogenic cysts histologically correspond to emphysema and bronchiolization or Þbrotic changes [59].

Patient Prognosis

The majority of bronchogenic cysts in adults are removed surgically.

Pneumatoceles in Staphylococcal

Pneumonia

Pathology and Pathogenesis

Pulmonary pneumatoceles are areas of regional obstructive emphysema usually developing as a complication (inßammatory narrowing of a bronchus) of staphylococcal pneumonia. They are thin-walled, air-containing, cyst-like structures which may occur at any age but are most frequently seen in infancy [33].

Symptoms and Signs

Staphylococcal pneumonia typically occurs in cases of inßuenza (airborne transmission) or nosocomial pneumonia, particularly ventilator-associated pneumonia. The clinical presentation of pneumonia caused by Staphylococcus aureus is usually similar to those by other etiological agents. However, rapid progression of pulmonary lesions, frequent complications such as pleural effusion, empyema and septic shock, and high mortality are not uncommon.

CT Findings

Most bronchogenic cysts are located in the mediastinum, but 10Ð30 % in the lung [57]. CT demonstrates a homogeneous cys-

The typical pattern of Staphylococcal pneumonia at presentation is bronchopneumonia manifested as centrilobular