In three of four cases of small cell carcinoma, the tumors had directly invaded the pulmonary artery adjacent to the affected bronchus, resulting in stenosis of the pulmonary artery within the lesion (Fig 5). In three cases, carcinoid tumors had grown out of the bronchial lumen across the bronchial wall, resulting in a characteristic snowman-like form, with the neck located at the cartilaginous part of the bronchus. Bleeding within the carcinoid tumor appeared as mottled hyperechoic areas on the EBUS images (Fig 6).
Internal echoes were homogeneous in cases of primary malignant lymphoma of the lung, and the appearance was similar to that of pneumonia. Large blood vessels remained patent within the lesions, suggesting that the lesions were soft. Echo-free areas with star-shaped margins were visible within the lesion in one case of inflammatory pseudotumor, corresponding to the lumen of the dilated bronchus.
Tumor Typing Based on the Internal Structure Visualized by EBUS
Histopathology was available for 124 lesions visualized by EBUS. The lesions were typed based on the internal echoes (whether homogenous or heterogenous), vascular patency, and the morphology of the hyperechoic areas (reflecting the presence of air and the state of the bronchi) [Table 2]. anti allergy
Type I: Homogeneous Pattern
Type Ia, Homogeneous Pattern With Patent Vessels and Patent Bronchioles: Seventeen lesions (13.7%) were classified as type Ia (Fig 7). The majority of these lesions (15) were pneumonia, characterized by exudate-filled alveoli. EBUS images of this type revealed normal blood vessels and normal bronchi, free of compression and stenosis, within the lesion. The internal echoes were homogeneous. Thus, the ultrasound attenuation was small, and even tissue 15 to 20 mm from the probe could be seen clearly. Because the lesions extended from one lobule to another, the margins were often linear in some parts. The type Ia group also included one case of organizing pneumonia and one case of metastasis from pancreatic cancer in addition to the 15 cases of pneumonia.
Figure 5. A representative case of small cell carcinoma. This small cell carcinoma had directly invaded the pulmonary artery (arrow) coursing along the affected bronchus, resulting in stenosis of the pulmonary artery within the lesion.
Figure 6. A representative case of carcinoid tumor. This carcinoid tumor had grown out of the bronchial lumen across the bronchial wall, resulting in a characteristic snowman-like form, with the neck located at the cartilaginous part of the bronchus. Bleeding within the carcinoid tumor was visible as mottled hyperechoic areas in the EBUS images.
Figure 7. EBUS images of a type Ia lesion revealed normal blood vessels and bronchi that were free of compression and stenosis. The internal echoes were homogeneous.
Table 2—Tumor Typing Based on the Inner Structures Visualized in the EBUS Images in the 124 Cases
|Type I||Type II||Type III|
|a(n = 17)||b(n = 8)||a(n = 13)||b(n = 11)||a(n = 53)||b(n = 22)|