Lung Lesion Biography
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A pulmonary sequestration (also known as a bronchopulmonary sequestration orcystic lung lesion), is a medical condition wherein a piece of tissue that ultimately develops into lung tissue is not attached to the pulmonary arterial blood supply, as is the case in normally developing lung. As a result, this sequestered tissue is not connected to the normal bronchial airway architecture, and as a result, fails to function in, and contribute to, respiration of the organism.
This condition is usually diagnosed in children and is generally thought to be congenital in nature. More and more, these lesions are diagnosed in utero by prenatal ultrasound. Bronchopulmonary sequestration (BPS) is a rare congenital malformation of the lower respiratory tract. It consists of a nonfunctioning mass of normal lung tissue that lacks normal communication with the tracheobronchial tree, and that receives its arterial blood supply from the systemic circulation. BPS is estimated to comprise 0.15 to 6.4 percent of all congenital pulmonary malformations, making it an extremely rare disorder. Sequestrations are classified anatomically. Intralobar sequestration (ILS) in which the lesion is located within a normal lobe and lacks its own visceral pleura. Extralobar sequestration (ELS) in which the mass is located outside the normal lung and has its own visceral pleura The blood supply of 75% of pulmonary sequestrations is derived from the thoracic or abdominal aorta. The remaining 25% of sequestrations receive their blood flow from the subclavian, intercostal, pulmonary, pericardiophrenic, innominate, internal mammary, celiac, splenic, or renal a rteries.
Usually the sequestration is removed after birth via surgery. In most cases this surgery is safe and effective; the child will grow up to have normal lung function. In a few instances, fetuses with sequestrations develop problematic fluid collections in the chest cavity. In these situations a Harrison catheter shunt can be used to drain the chest fluid into the amniotic fluid. In rare instances where the fetus has a very large lesion, resuscitation after delivery can be dangerous. In these situations a specialized delivery for management of the airway compression can be planned called the EXIT procedure, or a fetal laser ablation procedure can be performed. During this minimally invasive fetal intervention, a small needle is inserted into the sequestration, and a laser fiber is targeted at the abnormal blood vessel going to the sequestration. The goal of the operation is to use laser energy to stop the blood flow to the sequestration, causing it to stop growing. Ideally, after the surgery, the sequestration steals less blood flow from the fetus, and the heart and lungs start growing more normally as the sequestration shrinks in size and the pleural effusion goes away.
The treatment for this is a segmentectomy via a thoracotomy. Pulmonary sequestrations usually get their blood supply from the thoracic aorta. (intrapulmonary sequestration drains via pulmonary veins, extra pulmonary sequestration drains to the IVC) n radiology, a solitary pulmonary nodule (SPN) or coin lesion is a mass in the lungsmaller than 3 centimeters in diameter. It can be an incidental finding found in up to 0.2% of chest X-rays[ and around 1% of CT scans. The nodule most commonly represents a benign tumor such as a granuloma orhamartoma, but in around 20% of cases it represents a malignant cancer, especially inolder adults and smokers. Conversely, 10 to 20% of patients with lung cancer are diagnosed in this way. Thus, the possibility of cancer needs to be excluded through further radiological studies and interventions, possibly including surgical resection. Theprognosis depends on the underlying condition. A solitary pulmonary nodulus needs to be separated from larger lung tumors, smaller infiltrates or masses with other accompanying characteristics. An often used formal radiological definition is the following: a single lesion in the lung completely surrounded by lung parenchyma (functional tissue) with a diameter less than 3 cm and without associatedpneumonia, atelectasis (lung collapse) or lymphadenopathies (swollen lymph nodes). Several features help to distinguish benign conditions from possible lung cancer. The first parameter is the size of the lesion: the smaller, the less risk for malignant cancer. Benign causes tend to have a well defined border, whereas lobulated lesions or those with an irregular margin extending into the neighbouring tissue tend to be malignant. If there is a central cavity, then a thin wall points to a benign cause whereas a thick wall is associated with malignancy (especially 4mm or less versus 16mm or more). In lung cancer, cavitation can represent central tumor necrosis (tissue death) or secondary abscessformation. If the walls of an airway are visible (air bronchogram), bronchioloalveolar carcinomais a possibility.
An SPN often contains calcifications. Certain patterns of calcification are reassuring, such as the popcorn-like appearance of hamartoma. An SPN with a density below 15 Hounsfield units on computed tomography tends to be benign, whereas malignant tumors often measure more than 20 Hounsfield units. Fatty tissue inside hamartomas will have a strongly negative value on the Hounsfield scale. The growth velocity of a lesion is also informative: very fast or very slow growing tumors are rarely malignant, in contrary to inflammatory or congenital conditions. It is therefore important to retrieve previous imaging studies to see if a lesion was presented and how fast its volume is increasing. This is more difficult for nodules smaller than 1 centimeter. Moreover, the predictive value of stable lesion over a period of 2 years has been found to be rather low and unreliable.
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