Gross specimens in pathological anatomy

Macroscopic characteristics and parenchymal changes

The study of gross specimens allows for the visualization of gross structural abnormalities in organs. Using the example of pathologically altered lungs in bronchiectasis (Morbus bronchiectaticus), we observe a complex pattern of lesions. First and foremost, macroscopic examination draws attention to the state of the bronchial tree. The bronchial walls are pathologically thickened and surrounded by thick layers of connective tissue, making them visually dense and rigid.

The airways themselves undergo significant deformation. The most important morphological sign on the gross specimen is that the altered bronchi completely lose their natural connection with the distal divisions — the bronchioles. As a result of this loss of connection, the bronchi terminate in absolute blind ends, forming dead ends.

The pathological process is not limited to the bronchial tree alone; it inevitably extends to the surrounding tissue. In the affected area of the pulmonary parenchyma, two fundamentally opposing conditions develop: either atelectasis (complete collapse of the lung tissue) or emphysema (pathological expansion of air spaces).

Classification of morphological types based on gross specimens

Depending on the shape of the pathological bronchial dilation, which can be assessed both from intravital bronchography data and through direct study of gross specimens, pathological anatomy distinguishes three main morphological types. This classification is based exclusively on the visual geometry of the deformed areas:

1. Cylindrical — characterized by the fact that the bronchial lumen dilates completely uniformly over a certain, sometimes considerable, extent. On a gross specimen, such bronchi look like wide tubes of regular shape.
2. Saccular — distinguished by the formation of specific rounded cavities. These cavities, visually resembling sacs, are located strictly at the blind ends of the deformed bronchi where the connection with the bronchioles was lost.
3. Fusiform and mixed — present a picture of extremely uneven dilation. On the gross specimen, it is clearly visible how areas of pathological dilation alternate with areas of sharp narrowing, giving the bronchus a spindle shape or creating a mixed deformation.

Microscopic picture: the basis of macroscopic changes

To fully understand the gross specimen, one must examine the microscopic changes. The most pronounced pathomorphological shifts are observed at the level of the small bronchi. This entire destructive process is inextricably linked with the development of severe, prolonged inflammation, which proceeds as chronic mucous or purulent catarrhal inflammation.

It is important to note a critical feature of histological diagnosis: due to extremely pronounced purulent tissue lysis, the original structure of the wall is destroyed. For this reason, upon microscopic examination, it becomes practically impossible to reliably distinguish congenital pathological dilations of the bronchi from those acquired during life. Purulent lysis completely erases all differential criteria.

Structural changes of the wall at the tissue level

The thickening and deformation visible to the naked eye on the gross specimen are caused by profound changes at the cellular level. The main microscopic patterns include damage to all layers of the wall:

• Epithelial and glandular changes: Metaplasia of the lining epithelium occurs in the mucosa. Simultaneously, marked hyperplasia of the bronchial (mucous) glands and goblet cells develops.
• Structural changes of the wall: Massive inflammatory infiltration is observed within the tissue thickness. The muscular layer undergoes gradual atrophy, and the elastic fibers undergo complete destruction. Against the background of these destructions, sclerosis (proliferation of connective tissue) develops, which forms those very layers visible on the gross specimen.
• Polyp formation: Chronic inflammation stimulates the active proliferation of granulation tissue. This process often leads to the formation of specific inflammatory polyps protruding from the mucosal surface.

Class and exam questions

What else to study on this topic

• Etiology and triggers of bronchiectasis development
• Detailed pathogenesis of pathological dilation formation
• Complications of chronic purulent inflammation in lung tissue
• Main causes of death in this pulmonary pathology
• Bronchography as a method for visualizing bronchial tree deformations

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