Pulmonary tuberculoma

Tuberculosis of the lungs is a clinical form of tuberculosis, in which caseous necrotic lesion with a diameter of more than 12 mm forms in the lung tissue, separated from the adjacent lung tissue by a two-layer capsule.

[1], [2], [3], [4]

Epidemiology

Tuberculosis is found in 2-6% of newly diagnosed patients with respiratory tuberculosis, mainly in adults aged 20-35 years. More than half of the patients are detected by control fluorography, as most of them have no clear clinical signs of the disease.

[5], [6], [7],

Causes of the pulmonary tuberculomas

The development of tuberculosis occurs against the background of the hyperergic reaction of the cellular elements of the lung tissue to Mycobacterium tuberculosis and the increased activity of fibroplastic processes in the area of tuberculous inflammation. The formation of tuberculosis may be promoted by an incompletely adequate treatment of the disease, which leads to a more prolonged preservation of the pathogen population in the affected area.

[8], [9], [10], [11]

Pathogenesis

With inadequate reverse development of tuberculous inflammation, resorption and reduction in the size of the infiltrate are combined with an increase in the volume of caseous-necrotic masses in its central parts. Such dynamics is observed in the presence of highly virulent Mycobacterium strains in the infiltrate, as well as with increased tension of general and local cellular immunity. A layer of granulations appears around the centrally located zone of caseous necrosis, and collagen fibers form along its outer borders and a thin fibrous layer begins to form.

A small infiltrate with pronounced caseous-necrotic changes in the center can also form when several caseous foci merge. Such an infiltrate is also rather quickly encapsulated and transformed into tuberculosis.

Capsule tuberculosis consists of two layers. The inner layer, formed by tubercular granulations, surrounds the caseous nucleus of the tuberculosis. The outer layer is represented by concentrically arranged fibrous fibers. Delimits the tuberculosis from the adjacent slightly altered lung tissue. A massive caseous nucleus and a thin (1-1.5 mm), well-formed fibrous capsule are characteristic morphological signs of the most common type of tuberculosis - caseomas. For the infiltrative-pneumonic type of tuberculosis, alternating sections of caseous necrosis with epithelioid-cell tubercles and weak capsule development are characteristic.

Tuberculosis, which are formed from infiltrates and foci, is called true. From pathological positions, there are several types of true tuberculosis: solitary (homogeneous and layered) and conglomerate (homogeneous and layered).

The solitary homogeneous tuberculosis is represented by a rounded, caseous-necrotic focus, surrounded by a two-layer capsule. Conglomerate homogeneous tuberculosis consists of several small caseous foci united by a single two-layer capsule. In layered tuberculosis, the caseous nucleus is surrounded by concentric layers of fibrosing collagen fibers that alternate with cases of caseous necrosis. This indicates a wave-like process.

In many progressive tuberculosis, it is possible to detect the destruction sites formed as a result of the melting of the caseous masses and their resorption by phagocytes. Such processes occur only in the peripheral regions, there are no blood vessels in the central sections of the tuberculosis, and proteolytic enzymes and phagocytes do not penetrate into these sections. As a result, the decay in the tuberculosis has a regional location When the tuberculosis capsule is melted, conditions arise for communicating the decay cavity with the bronchus. In this case, caseous masses are rejected into the lumen of the bronchus and the size of the decay cavity increases.

Various adverse effects that suppress cellular immunity and alter hormonal levels in the body can lead to marked progression of tuberculosis with the development of caseous pneumonia or cavernous tuberculosis, followed by transformation into fibrous-cavernous pulmonary tuberculosis.

For the stationary course of this form of tuberculosis is characterized by the absence of perifocal infiltration and signs of disintegration in tuberculosis. In the tissue surrounding the tuberculosis, changes due to pneumofibrosis are visible. As well as dense. Without obvious signs of activity foci.

With a successive regressing course of the tuberculosis, the caseous masses become compacted and fragmented over time, the size of the tuberculosis slowly decreases, and it is gradually soaked with calcium salts. In its place a dense fibrous focus or a zone of limited pulmonary fibrosis may form. Sometimes, with a regressing course of tuberculosis, almost complete rejection of caseous masses can occur, after which a small thin-walled cavity remains, the walls of which are the former capsule of the tuberculosis. In the future, such a cavity is most often scarring. With involution, tuberculosis in the surrounding lung tissue is usually revealed by a few fibrous foci, cords formed by obliterated small vessels and bronchi.

A peculiar variant of the tuberculosis is considered to be a filled cavern, which is called a false tuberculoma or pseudotuberculoma. The blocked cavern is gradually filled with necrotic masses, lymph and cellular elements and is transformed into a rounded, circumscribed from the surrounding tissue volume education. The fibrous layer surrounding such a false tuberculosis is usually quite wide, and in the caseous masses there are no alveolar septa and other structural elements of the lung tissue.

The clinical course of tuberculosis is progressive, stationary and regressive.

[12], [13], [14]

Symptoms of the pulmonary tuberculomas

The isolated nature of the lesion in many patients causes oligosymptomatic, often inert, chronic tuberculosis. An exacerbation usually occurs under the influence of adverse factors of the external and internal environment, which reduce the likelihood of delimitation of specific inflammation in the lung. Patients noted weakness, loss of appetite, weight loss, and sometimes an increase in body temperature to 37.5-37.8 ° C. Chest pain associated with breathing, coughing (dry or with a small amount of sputum) may occur. In rare cases, hemoptysis occurs. The results of physical examination of the lungs depend on the size of the tuberculosis, its localization and the phase of the tuberculous process.

[15]

Diagnostics of the pulmonary tuberculomas

The main radiological syndrome in tuberculosis is a limited (focal) darkening, often located subpleurally, in the 1st, 2nd or 6th segments. Small (up to 2 cm in diameter), medium (2-4 cm in diameter) and large (more than 4 cm in diameter) tuberculosis, which can be single or multiple, are isolated.

Rounded, the correct form of darkening corresponds to the solitary tuberculosis. Irregular shape and polycyclic outer contour are characteristic of conglomerate tuberculosis. Often, a decay cavity is detected, which is eccentric and may have a different shape. In case of rejection of caseous masses through the bronchus, the disintegration cavity is located near the mouth of the draining bronchus.

The contours of the tuberculosis are usually clear. The blurring of the contours indicates perifocal infiltration, which appears during the progression of tuberculosis. When they also find a “path” to the lung root in the form of perivascular and peribronchial seals with foci of contamination in the surrounding lung tissue.

The inhomogeneity of the shadow of the tuberculosis may be due to the heterogeneity of the caseous masses: the presence of fibrous cords, calcinates, and destruction sites in them.

An important feature of the X-ray picture of tuberculosis is the presence of few polymorphic foci and pulmonary fibrosis in the surrounding lung tissue.

[16], [17], [18]